merge(3p/git): Merge git upstream at v2.26.2 r/808

11 files changed, 986 insertions, 252 deletions

diff --git a/third_party/git/git-gui/lib/blame.tcl b/third_party/git/git-gui/lib/blame.tcl
index a1aeb8b96e2d..62ec08366768 100644
--- a/third_party/git/git-gui/lib/blame.tcl
+++ b/third_party/git/git-gui/lib/blame.tcl
@@ -24,6 +24,7 @@ field w_cviewer  ; # pane showing commit message
 field finder     ; # find mini-dialog frame
 field gotoline   ; # line goto mini-dialog frame
 field status     ; # status mega-widget instance
+field status_operation ; # operation displayed by status mega-widget
 field old_height ; # last known height of $w.file_pane
 
 
@@ -274,6 +275,7 @@ constructor new {i_commit i_path i_jump} {
 	pack $w_cviewer -expand 1 -fill both
 
 	set status [::status_bar::new $w.status]
+	set status_operation {}
 
 	menu $w.ctxm -tearoff 0
 	$w.ctxm add command \
@@ -602,16 +604,23 @@ method _exec_blame {cur_w cur_d options cur_s} {
 	} else {
 		lappend options $commit
 	}
+
+	# We may recurse in from another call to _exec_blame and already have
+	# a status operation.
+	if {$status_operation == {}} {
+		set status_operation [$status start \
+			$cur_s \
+			[mc "lines annotated"]]
+	} else {
+		$status_operation restart $cur_s
+	}
+
 	lappend options -- $path
 	set fd [eval git_read --nice blame $options]
 	fconfigure $fd -blocking 0 -translation lf -encoding utf-8
 	fileevent $fd readable [cb _read_blame $fd $cur_w $cur_d]
 	set current_fd $fd
 	set blame_lines 0
-
-	$status start \
-		$cur_s \
-		[mc "lines annotated"]
 }
 
 method _read_blame {fd cur_w cur_d} {
@@ -806,10 +815,11 @@ method _read_blame {fd cur_w cur_d} {
 				[mc "Loading original location annotations..."]
 		} else {
 			set current_fd {}
-			$status stop [mc "Annotation complete."]
+			$status_operation stop [mc "Annotation complete."]
+			set status_operation {}
 		}
 	} else {
-		$status update $blame_lines $total_lines
+		$status_operation update $blame_lines $total_lines
 	}
 } ifdeleted { catch {close $fd} }
 
@@ -1124,7 +1134,7 @@ method _blameparent {} {
 			set diffcmd [list diff-tree --unified=0 $cparent $cmit -- $new_path]
 		}
 		if {[catch {set fd [eval git_read $diffcmd]} err]} {
-			$status stop [mc "Unable to display parent"]
+			$status_operation stop [mc "Unable to display parent"]
 			error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
 			return
 		}
diff --git a/third_party/git/git-gui/lib/branch.tcl b/third_party/git/git-gui/lib/branch.tcl
index 777eeb79c135..8b0c4858890f 100644
--- a/third_party/git/git-gui/lib/branch.tcl
+++ b/third_party/git/git-gui/lib/branch.tcl
@@ -8,6 +8,7 @@ proc load_all_heads {} {
 	set rh_len [expr {[string length $rh] + 1}]
 	set all_heads [list]
 	set fd [git_read for-each-ref --format=%(refname) $rh]
+	fconfigure $fd -translation binary -encoding utf-8
 	while {[gets $fd line] > 0} {
 		if {!$some_heads_tracking || ![is_tracking_branch $line]} {
 			lappend all_heads [string range $line $rh_len end]
@@ -24,6 +25,7 @@ proc load_all_tags {} {
 		--sort=-taggerdate \
 		--format=%(refname) \
 		refs/tags]
+	fconfigure $fd -translation binary -encoding utf-8
 	while {[gets $fd line] > 0} {
 		if {![regsub ^refs/tags/ $line {} name]} continue
 		lappend all_tags $name
diff --git a/third_party/git/git-gui/lib/checkout_op.tcl b/third_party/git/git-gui/lib/checkout_op.tcl
index 9e7412c446f7..21ea768d8036 100644
--- a/third_party/git/git-gui/lib/checkout_op.tcl
+++ b/third_party/git/git-gui/lib/checkout_op.tcl
@@ -341,9 +341,9 @@ method _readtree {} {
 	global HEAD
 
 	set readtree_d {}
-	$::main_status start \
+	set status_bar_operation [$::main_status start \
 		[mc "Updating working directory to '%s'..." [_name $this]] \
-		[mc "files checked out"]
+		[mc "files checked out"]]
 
 	set fd [git_read --stderr read-tree \
 		-m \
@@ -354,26 +354,27 @@ method _readtree {} {
 		$new_hash \
 		]
 	fconfigure $fd -blocking 0 -translation binary
-	fileevent $fd readable [cb _readtree_wait $fd]
+	fileevent $fd readable [cb _readtree_wait $fd $status_bar_operation]
 }
 
-method _readtree_wait {fd} {
+method _readtree_wait {fd status_bar_operation} {
 	global current_branch
 
 	set buf [read $fd]
-	$::main_status update_meter $buf
+	$status_bar_operation update_meter $buf
 	append readtree_d $buf
 
 	fconfigure $fd -blocking 1
 	if {![eof $fd]} {
 		fconfigure $fd -blocking 0
+		$status_bar_operation stop
 		return
 	}
 
 	if {[catch {close $fd}]} {
 		set err $readtree_d
 		regsub {^fatal: } $err {} err
-		$::main_status stop [mc "Aborted checkout of '%s' (file level merging is required)." [_name $this]]
+		$status_bar_operation stop [mc "Aborted checkout of '%s' (file level merging is required)." [_name $this]]
 		warn_popup [strcat [mc "File level merge required."] "
 
 $err
@@ -384,12 +385,12 @@ $err
 		return
 	}
 
-	$::main_status stop
+	$status_bar_operation stop
 	_after_readtree $this
 }
 
 method _after_readtree {} {
-	global selected_commit_type commit_type HEAD MERGE_HEAD PARENT
+	global commit_type HEAD MERGE_HEAD PARENT
 	global current_branch is_detached
 	global ui_comm
 
@@ -490,12 +491,12 @@ method _update_repo_state {} {
 	#    amend mode our file lists are accurate and we can avoid
 	#    the rescan.
 	#
-	global selected_commit_type commit_type HEAD MERGE_HEAD PARENT
+	global commit_type_is_amend commit_type HEAD MERGE_HEAD PARENT
 	global ui_comm
 
 	unlock_index
 	set name [_name $this]
-	set selected_commit_type new
+	set commit_type_is_amend 0
 	if {[string match amend* $commit_type]} {
 		$ui_comm delete 0.0 end
 		$ui_comm edit reset
diff --git a/third_party/git/git-gui/lib/choose_repository.tcl b/third_party/git/git-gui/lib/choose_repository.tcl
index 80f5a59bbbfc..e54f3e66d8f0 100644
--- a/third_party/git/git-gui/lib/choose_repository.tcl
+++ b/third_party/git/git-gui/lib/choose_repository.tcl
@@ -9,6 +9,18 @@ field w_body      ; # Widget holding the center content
 field w_next      ; # Next button
 field w_quit      ; # Quit button
 field o_cons      ; # Console object (if active)
+
+# Status mega-widget instance during _do_clone2 (used by _copy_files and
+# _link_files). Widget is destroyed before _do_clone2 calls
+# _do_clone_checkout
+field o_status
+
+# Operation displayed by status mega-widget during _do_clone_checkout =>
+# _readtree_wait => _postcheckout_wait => _do_clone_submodules =>
+# _do_validate_submodule_cloning. The status mega-widget is a different
+# instance than that stored in $o_status in earlier operations.
+field o_status_op
+
 field w_types     ; # List of type buttons in clone
 field w_recentlist ; # Listbox containing recent repositories
 field w_localpath  ; # Entry widget bound to local_path
@@ -659,12 +671,12 @@ method _do_clone2 {} {
 
 	switch -exact -- $clone_type {
 	hardlink {
-		set o_cons [status_bar::two_line $w_body]
+		set o_status [status_bar::two_line $w_body]
 		pack $w_body -fill x -padx 10 -pady 10
 
-		$o_cons start \
+		set status_op [$o_status start \
 			[mc "Counting objects"] \
-			[mc "buckets"]
+			[mc "buckets"]]
 		update
 
 		if {[file exists [file join $objdir info alternates]]} {
@@ -689,6 +701,7 @@ method _do_clone2 {} {
 			} err]} {
 				catch {cd $pwd}
 				_clone_failed $this [mc "Unable to copy objects/info/alternates: %s" $err]
+				$status_op stop
 				return
 			}
 		}
@@ -700,7 +713,7 @@ method _do_clone2 {} {
 			-directory [file join $objdir] ??]
 		set bcnt [expr {[llength $buckets] + 2}]
 		set bcur 1
-		$o_cons update $bcur $bcnt
+		$status_op update $bcur $bcnt
 		update
 
 		file mkdir [file join .git objects pack]
@@ -708,7 +721,7 @@ method _do_clone2 {} {
 			-directory [file join $objdir pack] *] {
 			lappend tolink [file join pack $i]
 		}
-		$o_cons update [incr bcur] $bcnt
+		$status_op update [incr bcur] $bcnt
 		update
 
 		foreach i $buckets {
@@ -717,10 +730,10 @@ method _do_clone2 {} {
 				-directory [file join $objdir $i] *] {
 				lappend tolink [file join $i $j]
 			}
-			$o_cons update [incr bcur] $bcnt
+			$status_op update [incr bcur] $bcnt
 			update
 		}
-		$o_cons stop
+		$status_op stop
 
 		if {$tolink eq {}} {
 			info_popup [strcat \
@@ -747,6 +760,8 @@ method _do_clone2 {} {
 		if {!$i} return
 
 		destroy $w_body
+
+		set o_status {}
 	}
 	full {
 		set o_cons [console::embed \
@@ -781,9 +796,9 @@ method _do_clone2 {} {
 }
 
 method _copy_files {objdir tocopy} {
-	$o_cons start \
+	set status_op [$o_status start \
 		[mc "Copying objects"] \
-		[mc "KiB"]
+		[mc "KiB"]]
 	set tot 0
 	set cmp 0
 	foreach p $tocopy {
@@ -798,7 +813,7 @@ method _copy_files {objdir tocopy} {
 
 				while {![eof $f_in]} {
 					incr cmp [fcopy $f_in $f_cp -size 16384]
-					$o_cons update \
+					$status_op update \
 						[expr {$cmp / 1024}] \
 						[expr {$tot / 1024}]
 					update
@@ -808,17 +823,19 @@ method _copy_files {objdir tocopy} {
 				close $f_cp
 			} err]} {
 			_clone_failed $this [mc "Unable to copy object: %s" $err]
+			$status_op stop
 			return 0
 		}
 	}
+	$status_op stop
 	return 1
 }
 
 method _link_files {objdir tolink} {
 	set total [llength $tolink]
-	$o_cons start \
+	set status_op [$o_status start \
 		[mc "Linking objects"] \
-		[mc "objects"]
+		[mc "objects"]]
 	for {set i 0} {$i < $total} {} {
 		set p [lindex $tolink $i]
 		if {[catch {
@@ -827,15 +844,17 @@ method _link_files {objdir tolink} {
 					[file join $objdir $p]
 			} err]} {
 			_clone_failed $this [mc "Unable to hardlink object: %s" $err]
+			$status_op stop
 			return 0
 		}
 
 		incr i
 		if {$i % 5 == 0} {
-			$o_cons update $i $total
+			$status_op update $i $total
 			update
 		}
 	}
+	$status_op stop
 	return 1
 }
 
@@ -958,11 +977,26 @@ method _do_clone_checkout {HEAD} {
 		return
 	}
 
-	set o_cons [status_bar::two_line $w_body]
+	set status [status_bar::two_line $w_body]
 	pack $w_body -fill x -padx 10 -pady 10
-	$o_cons start \
+
+	# We start the status operation here.
+	#
+	# This function calls _readtree_wait as a callback.
+	#
+	# _readtree_wait in turn either calls _do_clone_submodules directly,
+	# or calls _postcheckout_wait as a callback which then calls
+	# _do_clone_submodules.
+	#
+	# _do_clone_submodules calls _do_validate_submodule_cloning.
+	#
+	# _do_validate_submodule_cloning stops the status operation.
+	#
+	# There are no other calls into this chain from other code.
+
+	set o_status_op [$status start \
 		[mc "Creating working directory"] \
-		[mc "files"]
+		[mc "files"]]
 
 	set readtree_err {}
 	set fd [git_read --stderr read-tree \
@@ -976,33 +1010,9 @@ method _do_clone_checkout {HEAD} {
 	fileevent $fd readable [cb _readtree_wait $fd]
 }
 
-method _do_validate_submodule_cloning {ok} {
-	if {$ok} {
-		$o_cons done $ok
-		set done 1
-	} else {
-		_clone_failed $this [mc "Cannot clone submodules."]
-	}
-}
-
-method _do_clone_submodules {} {
-	if {$recursive eq {true}} {
-		destroy $w_body
-		set o_cons [console::embed \
-			$w_body \
-			[mc "Cloning submodules"]]
-		pack $w_body -fill both -expand 1 -padx 10
-		$o_cons exec \
-			[list git submodule update --init --recursive] \
-			[cb _do_validate_submodule_cloning]
-	} else {
-		set done 1
-	}
-}
-
 method _readtree_wait {fd} {
 	set buf [read $fd]
-	$o_cons update_meter $buf
+	$o_status_op update_meter $buf
 	append readtree_err $buf
 
 	fconfigure $fd -blocking 1
@@ -1050,6 +1060,34 @@ method _postcheckout_wait {fd_ph} {
 	fconfigure $fd_ph -blocking 0
 }
 
+method _do_clone_submodules {} {
+	if {$recursive eq {true}} {
+		$o_status_op stop
+		set o_status_op {}
+
+		destroy $w_body
+
+		set o_cons [console::embed \
+			$w_body \
+			[mc "Cloning submodules"]]
+		pack $w_body -fill both -expand 1 -padx 10
+		$o_cons exec \
+			[list git submodule update --init --recursive] \
+			[cb _do_validate_submodule_cloning]
+	} else {
+		set done 1
+	}
+}
+
+method _do_validate_submodule_cloning {ok} {
+	if {$ok} {
+		$o_cons done $ok
+		set done 1
+	} else {
+		_clone_failed $this [mc "Cannot clone submodules."]
+	}
+}
+
 ######################################################################
 ##
 ## Open Existing Repository
diff --git a/third_party/git/git-gui/lib/chord.tcl b/third_party/git/git-gui/lib/chord.tcl
new file mode 100644
index 000000000000..e21e7d3d0b79
--- /dev/null
+++ b/third_party/git/git-gui/lib/chord.tcl
@@ -0,0 +1,158 @@
+# Simple Chord for Tcl
+#
+# A "chord" is a method with more than one entrypoint and only one body, such
+# that the body runs only once all the entrypoints have been called by
+# different asynchronous tasks. In this implementation, the chord is defined
+# dynamically for each invocation. A SimpleChord object is created, supplying
+# body script to be run when the chord is completed, and then one or more notes
+# are added to the chord. Each note can be called like a proc, and returns
+# immediately if the chord isn't yet complete. When the last remaining note is
+# called, the body runs before the note returns.
+#
+# The SimpleChord class has a constructor that takes the body script, and a
+# method add_note that returns a note object. Since the body script does not
+# run in the context of the procedure that defined it, a mechanism is provided
+# for injecting variables into the chord for use by the body script. The
+# activation of a note is idempotent; multiple calls have the same effect as
+# a simple call.
+#
+# If you are invoking asynchronous operations with chord notes as completion
+# callbacks, and there is a possibility that earlier operations could complete
+# before later ones are started, it is a good practice to create a "common"
+# note on the chord that prevents it from being complete until you're certain
+# you've added all the notes you need.
+#
+# Example:
+#
+#   # Turn off the UI while running a couple of async operations.
+#   lock_ui
+#
+#   set chord [SimpleChord::new {
+#     unlock_ui
+#     # Note: $notice here is not referenced in the calling scope
+#     if {$notice} { info_popup $notice }
+#   }
+#
+#   # Configure a note to keep the chord from completing until
+#   # all operations have been initiated.
+#   set common_note [$chord add_note]
+#
+#   # Activate notes in 'after' callbacks to other operations
+#   set newnote [$chord add_note]
+#   async_operation $args [list $newnote activate]
+#
+#   # Communicate with the chord body
+#   if {$condition} {
+#     # This sets $notice in the same context that the chord body runs in.
+#     $chord eval { set notice "Something interesting" }
+#   }
+#
+#   # Activate the common note, making the chord eligible to complete
+#   $common_note activate
+#
+# At this point, the chord will complete at some unknown point in the future.
+# The common note might have been the first note activated, or the async
+# operations might have completed synchronously and the common note is the
+# last one, completing the chord before this code finishes, or anything in
+# between. The purpose of the chord is to not have to worry about the order.
+
+# SimpleChord class:
+#   Represents a procedure that conceptually has multiple entrypoints that must
+#   all be called before the procedure executes. Each entrypoint is called a
+#   "note". The chord is only "completed" when all the notes are "activated".
+class SimpleChord {
+	field notes
+	field body
+	field is_completed
+	field eval_ns
+
+	# Constructor:
+	#   set chord [SimpleChord::new {body}]
+	#     Creates a new chord object with the specified body script. The
+	#     body script is evaluated at most once, when a note is activated
+	#     and the chord has no other non-activated notes.
+	constructor new {i_body} {
+		set notes [list]
+		set body $i_body
+		set is_completed 0
+		set eval_ns "[namespace qualifiers $this]::eval"
+		return $this
+	}
+
+	# Method:
+	#   $chord eval {script}
+	#     Runs the specified script in the same context (namespace) in which
+	#     the chord body will be evaluated. This can be used to set variable
+	#     values for the chord body to use.
+	method eval {script} {
+		namespace eval $eval_ns $script
+	}
+
+	# Method:
+	#   set note [$chord add_note]
+	#     Adds a new note to the chord, an instance of ChordNote. Raises an
+	#     error if the chord is already completed, otherwise the chord is
+	#     updated so that the new note must also be activated before the
+	#     body is evaluated.
+	method add_note {} {
+		if {$is_completed} { error "Cannot add a note to a completed chord" }
+
+		set note [ChordNote::new $this]
+
+		lappend notes $note
+
+		return $note
+	}
+
+	# This method is for internal use only and is intentionally undocumented.
+	method notify_note_activation {} {
+		if {!$is_completed} {
+			foreach note $notes {
+				if {![$note is_activated]} { return }
+			}
+
+			set is_completed 1
+
+			namespace eval $eval_ns $body
+			delete_this
+		}
+	}
+}
+
+# ChordNote class:
+#   Represents a note within a chord, providing a way to activate it. When the
+#   final note of the chord is activated (this can be any note in the chord,
+#   with all other notes already previously activated in any order), the chord's
+#   body is evaluated.
+class ChordNote {
+	field chord
+	field is_activated
+
+	# Constructor:
+	#   Instances of ChordNote are created internally by calling add_note on
+	#   SimpleChord objects.
+	constructor new {c} {
+		set chord $c
+		set is_activated 0
+		return $this
+	}
+
+	# Method:
+	#   [$note is_activated]
+	#     Returns true if this note has already been activated.
+	method is_activated {} {
+		return $is_activated
+	}
+
+	# Method:
+	#   $note activate
+	#     Activates the note, if it has not already been activated, and
+	#     completes the chord if there are no other notes awaiting
+	#     activation. Subsequent calls will have no further effect.
+	method activate {} {
+		if {!$is_activated} {
+			set is_activated 1
+			$chord notify_note_activation
+		}
+	}
+}
diff --git a/third_party/git/git-gui/lib/commit.tcl b/third_party/git/git-gui/lib/commit.tcl
index 75ea965dacd7..b516aa299069 100644
--- a/third_party/git/git-gui/lib/commit.tcl
+++ b/third_party/git/git-gui/lib/commit.tcl
@@ -333,7 +333,7 @@ proc commit_writetree {curHEAD msg_p} {
 proc commit_committree {fd_wt curHEAD msg_p} {
 	global HEAD PARENT MERGE_HEAD commit_type commit_author
 	global current_branch
-	global ui_comm selected_commit_type
+	global ui_comm commit_type_is_amend
 	global file_states selected_paths rescan_active
 	global repo_config
 	global env
@@ -467,8 +467,8 @@ A rescan will be automatically started now.
 
 	# -- Update in memory status
 	#
-	set selected_commit_type new
 	set commit_type normal
+	set commit_type_is_amend 0
 	set HEAD $cmt_id
 	set PARENT $cmt_id
 	set MERGE_HEAD [list]
diff --git a/third_party/git/git-gui/lib/console.tcl b/third_party/git/git-gui/lib/console.tcl
index 1f3248ffd113..bb6b9c889e20 100644
--- a/third_party/git/git-gui/lib/console.tcl
+++ b/third_party/git/git-gui/lib/console.tcl
@@ -203,6 +203,8 @@ method done {ok} {
 			focus $w.ok
 		}
 	}
+
+	bind $w <Key-Escape> "destroy $w;break"
 }
 
 method _sb_set {sb orient first last} {
diff --git a/third_party/git/git-gui/lib/diff.tcl b/third_party/git/git-gui/lib/diff.tcl
index 68c4a6c7366f..871ad488c2a1 100644
--- a/third_party/git/git-gui/lib/diff.tcl
+++ b/third_party/git/git-gui/lib/diff.tcl
@@ -55,7 +55,7 @@ proc reshow_diff {{after {}}} {
 
 proc force_diff_encoding {enc} {
 	global current_diff_path
-	
+
 	if {$current_diff_path ne {}} {
 		force_path_encoding $current_diff_path $enc
 		reshow_diff
@@ -270,19 +270,6 @@ proc show_other_diff {path w m cont_info} {
 	}
 }
 
-proc get_conflict_marker_size {path} {
-	set size 7
-	catch {
-		set fd_rc [eval [list git_read check-attr "conflict-marker-size" -- $path]]
-		set ret [gets $fd_rc line]
-		close $fd_rc
-		if {$ret > 0} {
-			regexp {.*: conflict-marker-size: (\d+)$} $line line size
-		}
-	}
-	return $size
-}
-
 proc start_show_diff {cont_info {add_opts {}}} {
 	global file_states file_lists
 	global is_3way_diff is_submodule_diff diff_active repo_config
@@ -298,7 +285,7 @@ proc start_show_diff {cont_info {add_opts {}}} {
 	set is_submodule_diff 0
 	set diff_active 1
 	set current_diff_header {}
-	set conflict_size [get_conflict_marker_size $path]
+	set conflict_size [gitattr $path conflict-marker-size 7]
 
 	set cmd [list]
 	if {$w eq $ui_index} {
@@ -360,6 +347,10 @@ proc start_show_diff {cont_info {add_opts {}}} {
 	}
 
 	set ::current_diff_inheader 1
+	# Detect pre-image lines of the diff3 conflict-style. They are just
+	# '++' lines which is not bijective. Thus, we need to maintain a state
+	# across lines.
+	set ::conflict_in_pre_image 0
 	fconfigure $fd \
 		-blocking 0 \
 		-encoding [get_path_encoding $path] \
@@ -462,11 +453,23 @@ proc read_diff {fd conflict_size cont_info} {
 			{--} {set tags d_--}
 			{++} {
 				set regexp [string map [list %conflict_size $conflict_size]\
-								{^\+\+([<>=]){%conflict_size}(?: |$)}]
+								{^\+\+([<>=|]){%conflict_size}(?: |$)}]
 				if {[regexp $regexp $line _g op]} {
 					set is_conflict_diff 1
 					set line [string replace $line 0 1 {  }]
 					set tags d$op
+
+					# The ||| conflict-marker marks the start of the pre-image.
+					# All those lines are also prefixed with '++'. Thus we need
+					# to maintain this state.
+					set ::conflict_in_pre_image [expr {$op eq {|}}]
+				} elseif {$::conflict_in_pre_image} {
+					# This is a pre-image line. It is the one which both sides
+					# are based on. As it has also the '++' line start, it is
+					# normally shown as 'added'. Invert this to '--' to make
+					# it a 'removed' line.
+					set line [string replace $line 0 1 {--}]
+					set tags d_--
 				} else {
 					set tags d_++
 				}
@@ -567,24 +570,31 @@ proc read_diff {fd conflict_size cont_info} {
 	}
 }
 
-proc apply_hunk {x y} {
+proc apply_or_revert_hunk {x y revert} {
 	global current_diff_path current_diff_header current_diff_side
-	global ui_diff ui_index file_states
+	global ui_diff ui_index file_states last_revert last_revert_enc
 
 	if {$current_diff_path eq {} || $current_diff_header eq {}} return
 	if {![lock_index apply_hunk]} return
 
-	set apply_cmd {apply --cached --whitespace=nowarn}
+	set apply_cmd {apply --whitespace=nowarn}
 	set mi [lindex $file_states($current_diff_path) 0]
 	if {$current_diff_side eq $ui_index} {
 		set failed_msg [mc "Failed to unstage selected hunk."]
-		lappend apply_cmd --reverse
+		lappend apply_cmd --reverse --cached
 		if {[string index $mi 0] ne {M}} {
 			unlock_index
 			return
 		}
 	} else {
-		set failed_msg [mc "Failed to stage selected hunk."]
+		if {$revert} {
+			set failed_msg [mc "Failed to revert selected hunk."]
+			lappend apply_cmd --reverse
+		} else {
+			set failed_msg [mc "Failed to stage selected hunk."]
+			lappend apply_cmd --cached
+		}
+
 		if {[string index $mi 1] ne {M}} {
 			unlock_index
 			return
@@ -603,29 +613,40 @@ proc apply_hunk {x y} {
 		set e_lno end
 	}
 
+	set wholepatch "$current_diff_header[$ui_diff get $s_lno $e_lno]"
+
 	if {[catch {
 		set enc [get_path_encoding $current_diff_path]
 		set p [eval git_write $apply_cmd]
 		fconfigure $p -translation binary -encoding $enc
-		puts -nonewline $p $current_diff_header
-		puts -nonewline $p [$ui_diff get $s_lno $e_lno]
+		puts -nonewline $p $wholepatch
 		close $p} err]} {
 		error_popup "$failed_msg\n\n$err"
 		unlock_index
 		return
 	}
 
+	if {$revert} {
+		# Save a copy of this patch for undoing reverts.
+		set last_revert $wholepatch
+		set last_revert_enc $enc
+	}
+
 	$ui_diff conf -state normal
 	$ui_diff delete $s_lno $e_lno
 	$ui_diff conf -state disabled
 
+	# Check if the hunk was the last one in the file.
 	if {[$ui_diff get 1.0 end] eq "\n"} {
 		set o _
 	} else {
 		set o ?
 	}
 
-	if {$current_diff_side eq $ui_index} {
+	# Update the status flags.
+	if {$revert} {
+		set mi [string index $mi 0]$o
+	} elseif {$current_diff_side eq $ui_index} {
 		set mi ${o}M
 	} elseif {[string index $mi 0] eq {_}} {
 		set mi M$o
@@ -640,9 +661,9 @@ proc apply_hunk {x y} {
 	}
 }
 
-proc apply_range_or_line {x y} {
+proc apply_or_revert_range_or_line {x y revert} {
 	global current_diff_path current_diff_header current_diff_side
-	global ui_diff ui_index file_states
+	global ui_diff ui_index file_states last_revert
 
 	set selected [$ui_diff tag nextrange sel 0.0]
 
@@ -660,19 +681,27 @@ proc apply_range_or_line {x y} {
 	if {$current_diff_path eq {} || $current_diff_header eq {}} return
 	if {![lock_index apply_hunk]} return
 
-	set apply_cmd {apply --cached --whitespace=nowarn}
+	set apply_cmd {apply --whitespace=nowarn}
 	set mi [lindex $file_states($current_diff_path) 0]
 	if {$current_diff_side eq $ui_index} {
 		set failed_msg [mc "Failed to unstage selected line."]
 		set to_context {+}
-		lappend apply_cmd --reverse
+		lappend apply_cmd --reverse --cached
 		if {[string index $mi 0] ne {M}} {
 			unlock_index
 			return
 		}
 	} else {
-		set failed_msg [mc "Failed to stage selected line."]
-		set to_context {-}
+		if {$revert} {
+			set failed_msg [mc "Failed to revert selected line."]
+			set to_context {+}
+			lappend apply_cmd --reverse
+		} else {
+			set failed_msg [mc "Failed to stage selected line."]
+			set to_context {-}
+			lappend apply_cmd --cached
+		}
+
 		if {[string index $mi 1] ne {M}} {
 			unlock_index
 			return
@@ -830,7 +859,47 @@ proc apply_range_or_line {x y} {
 		puts -nonewline $p $wholepatch
 		close $p} err]} {
 		error_popup "$failed_msg\n\n$err"
+		unlock_index
+		return
+	}
+
+	if {$revert} {
+		# Save a copy of this patch for undoing reverts.
+		set last_revert $current_diff_header$wholepatch
+		set last_revert_enc $enc
+	}
+
+	unlock_index
+}
+
+# Undo the last line/hunk reverted. When hunks and lines are reverted, a copy
+# of the diff applied is saved. Re-apply that diff to undo the revert.
+#
+# Right now, we only use a single variable to hold the copy, and not a
+# stack/deque for simplicity, so multiple undos are not possible. Maybe this
+# can be added if the need for something like this is felt in the future.
+proc undo_last_revert {} {
+	global last_revert current_diff_path current_diff_header
+	global last_revert_enc
+
+	if {$last_revert eq {}} return
+	if {![lock_index apply_hunk]} return
+
+	set apply_cmd {apply --whitespace=nowarn}
+	set failed_msg [mc "Failed to undo last revert."]
+
+	if {[catch {
+		set enc $last_revert_enc
+		set p [eval git_write $apply_cmd]
+		fconfigure $p -translation binary -encoding $enc
+		puts -nonewline $p $last_revert
+		close $p} err]} {
+		error_popup "$failed_msg\n\n$err"
+		unlock_index
+		return
 	}
 
+	set last_revert {}
+
 	unlock_index
 }
diff --git a/third_party/git/git-gui/lib/index.tcl b/third_party/git/git-gui/lib/index.tcl
index b588db11d9fc..1fc5b42300d6 100644
--- a/third_party/git/git-gui/lib/index.tcl
+++ b/third_party/git/git-gui/lib/index.tcl
@@ -7,67 +7,74 @@ proc _delete_indexlock {} {
 	}
 }
 
-proc _close_updateindex {fd after} {
-	global use_ttk NS
-	fconfigure $fd -blocking 1
-	if {[catch {close $fd} err]} {
-		set w .indexfried
-		Dialog $w
-		wm withdraw $w
-		wm title $w [strcat "[appname] ([reponame]): " [mc "Index Error"]]
-		wm geometry $w "+[winfo rootx .]+[winfo rooty .]"
-		set s [mc "Updating the Git index failed.  A rescan will be automatically started to resynchronize git-gui."]
-		text $w.msg -yscrollcommand [list $w.vs set] \
-			-width [string length $s] -relief flat \
-			-borderwidth 0 -highlightthickness 0 \
-			-background [get_bg_color $w]
-		$w.msg tag configure bold -font font_uibold -justify center
-		${NS}::scrollbar $w.vs -command [list $w.msg yview]
-		$w.msg insert end $s bold \n\n$err {}
-		$w.msg configure -state disabled
-
-		${NS}::button $w.continue \
-			-text [mc "Continue"] \
-			-command [list destroy $w]
-		${NS}::button $w.unlock \
-			-text [mc "Unlock Index"] \
-			-command "destroy $w; _delete_indexlock"
-		grid $w.msg - $w.vs -sticky news
-		grid $w.unlock $w.continue - -sticky se -padx 2 -pady 2
-		grid columnconfigure $w 0 -weight 1
-		grid rowconfigure $w 0 -weight 1
-
-		wm protocol $w WM_DELETE_WINDOW update
-		bind $w.continue <Visibility> "
-			grab $w
-			focus %W
-		"
-		wm deiconify $w
-		tkwait window $w
-
-		$::main_status stop
+proc close_and_unlock_index {fd after} {
+	if {![catch {_close_updateindex $fd} err]} {
 		unlock_index
-		rescan $after 0
-		return
+		uplevel #0 $after
+	} else {
+		rescan_on_error $err $after
 	}
+}
 
-	$::main_status stop
+proc _close_updateindex {fd} {
+	fconfigure $fd -blocking 1
+	close $fd
+}
+
+proc rescan_on_error {err {after {}}} {
+	global use_ttk NS
+
+	set w .indexfried
+	Dialog $w
+	wm withdraw $w
+	wm title $w [strcat "[appname] ([reponame]): " [mc "Index Error"]]
+	wm geometry $w "+[winfo rootx .]+[winfo rooty .]"
+	set s [mc "Updating the Git index failed.  A rescan will be automatically started to resynchronize git-gui."]
+	text $w.msg -yscrollcommand [list $w.vs set] \
+		-width [string length $s] -relief flat \
+		-borderwidth 0 -highlightthickness 0 \
+		-background [get_bg_color $w]
+	$w.msg tag configure bold -font font_uibold -justify center
+	${NS}::scrollbar $w.vs -command [list $w.msg yview]
+	$w.msg insert end $s bold \n\n$err {}
+	$w.msg configure -state disabled
+
+	${NS}::button $w.continue \
+		-text [mc "Continue"] \
+		-command [list destroy $w]
+	${NS}::button $w.unlock \
+		-text [mc "Unlock Index"] \
+		-command "destroy $w; _delete_indexlock"
+	grid $w.msg - $w.vs -sticky news
+	grid $w.unlock $w.continue - -sticky se -padx 2 -pady 2
+	grid columnconfigure $w 0 -weight 1
+	grid rowconfigure $w 0 -weight 1
+
+	wm protocol $w WM_DELETE_WINDOW update
+	bind $w.continue <Visibility> "
+		grab $w
+		focus %W
+	"
+	wm deiconify $w
+	tkwait window $w
+
+	$::main_status stop_all
 	unlock_index
-	uplevel #0 $after
+	rescan [concat $after [list ui_ready]] 0
 }
 
-proc update_indexinfo {msg pathList after} {
+proc update_indexinfo {msg path_list after} {
 	global update_index_cp
 
 	if {![lock_index update]} return
 
 	set update_index_cp 0
-	set pathList [lsort $pathList]
-	set totalCnt [llength $pathList]
-	set batch [expr {int($totalCnt * .01) + 1}]
+	set path_list [lsort $path_list]
+	set total_cnt [llength $path_list]
+	set batch [expr {int($total_cnt * .01) + 1}]
 	if {$batch > 25} {set batch 25}
 
-	$::main_status start $msg [mc "files"]
+	set status_bar_operation [$::main_status start $msg [mc "files"]]
 	set fd [git_write update-index -z --index-info]
 	fconfigure $fd \
 		-blocking 0 \
@@ -78,26 +85,29 @@ proc update_indexinfo {msg pathList after} {
 	fileevent $fd writable [list \
 		write_update_indexinfo \
 		$fd \
-		$pathList \
-		$totalCnt \
+		$path_list \
+		$total_cnt \
 		$batch \
+		$status_bar_operation \
 		$after \
 		]
 }
 
-proc write_update_indexinfo {fd pathList totalCnt batch after} {
+proc write_update_indexinfo {fd path_list total_cnt batch status_bar_operation \
+	after} {
 	global update_index_cp
 	global file_states current_diff_path
 
-	if {$update_index_cp >= $totalCnt} {
-		_close_updateindex $fd $after
+	if {$update_index_cp >= $total_cnt} {
+		$status_bar_operation stop
+		close_and_unlock_index $fd $after
 		return
 	}
 
 	for {set i $batch} \
-		{$update_index_cp < $totalCnt && $i > 0} \
+		{$update_index_cp < $total_cnt && $i > 0} \
 		{incr i -1} {
-		set path [lindex $pathList $update_index_cp]
+		set path [lindex $path_list $update_index_cp]
 		incr update_index_cp
 
 		set s $file_states($path)
@@ -119,21 +129,21 @@ proc write_update_indexinfo {fd pathList totalCnt batch after} {
 		display_file $path $new
 	}
 
-	$::main_status update $update_index_cp $totalCnt
+	$status_bar_operation update $update_index_cp $total_cnt
 }
 
-proc update_index {msg pathList after} {
+proc update_index {msg path_list after} {
 	global update_index_cp
 
 	if {![lock_index update]} return
 
 	set update_index_cp 0
-	set pathList [lsort $pathList]
-	set totalCnt [llength $pathList]
-	set batch [expr {int($totalCnt * .01) + 1}]
+	set path_list [lsort $path_list]
+	set total_cnt [llength $path_list]
+	set batch [expr {int($total_cnt * .01) + 1}]
 	if {$batch > 25} {set batch 25}
 
-	$::main_status start $msg [mc "files"]
+	set status_bar_operation [$::main_status start $msg [mc "files"]]
 	set fd [git_write update-index --add --remove -z --stdin]
 	fconfigure $fd \
 		-blocking 0 \
@@ -144,26 +154,29 @@ proc update_index {msg pathList after} {
 	fileevent $fd writable [list \
 		write_update_index \
 		$fd \
-		$pathList \
-		$totalCnt \
+		$path_list \
+		$total_cnt \
 		$batch \
+		$status_bar_operation \
 		$after \
 		]
 }
 
-proc write_update_index {fd pathList totalCnt batch after} {
+proc write_update_index {fd path_list total_cnt batch status_bar_operation \
+	after} {
 	global update_index_cp
 	global file_states current_diff_path
 
-	if {$update_index_cp >= $totalCnt} {
-		_close_updateindex $fd $after
+	if {$update_index_cp >= $total_cnt} {
+		$status_bar_operation stop
+		close_and_unlock_index $fd $after
 		return
 	}
 
 	for {set i $batch} \
-		{$update_index_cp < $totalCnt && $i > 0} \
+		{$update_index_cp < $total_cnt && $i > 0} \
 		{incr i -1} {
-		set path [lindex $pathList $update_index_cp]
+		set path [lindex $path_list $update_index_cp]
 		incr update_index_cp
 
 		switch -glob -- [lindex $file_states($path) 0] {
@@ -190,21 +203,21 @@ proc write_update_index {fd pathList totalCnt batch after} {
 		display_file $path $new
 	}
 
-	$::main_status update $update_index_cp $totalCnt
+	$status_bar_operation update $update_index_cp $total_cnt
 }
 
-proc checkout_index {msg pathList after} {
+proc checkout_index {msg path_list after capture_error} {
 	global update_index_cp
 
 	if {![lock_index update]} return
 
 	set update_index_cp 0
-	set pathList [lsort $pathList]
-	set totalCnt [llength $pathList]
-	set batch [expr {int($totalCnt * .01) + 1}]
+	set path_list [lsort $path_list]
+	set total_cnt [llength $path_list]
+	set batch [expr {int($total_cnt * .01) + 1}]
 	if {$batch > 25} {set batch 25}
 
-	$::main_status start $msg [mc "files"]
+	set status_bar_operation [$::main_status start $msg [mc "files"]]
 	set fd [git_write checkout-index \
 		--index \
 		--quiet \
@@ -221,26 +234,45 @@ proc checkout_index {msg pathList after} {
 	fileevent $fd writable [list \
 		write_checkout_index \
 		$fd \
-		$pathList \
-		$totalCnt \
+		$path_list \
+		$total_cnt \
 		$batch \
+		$status_bar_operation \
 		$after \
+		$capture_error \
 		]
 }
 
-proc write_checkout_index {fd pathList totalCnt batch after} {
+proc write_checkout_index {fd path_list total_cnt batch status_bar_operation \
+	after capture_error} {
 	global update_index_cp
 	global file_states current_diff_path
 
-	if {$update_index_cp >= $totalCnt} {
-		_close_updateindex $fd $after
+	if {$update_index_cp >= $total_cnt} {
+		$status_bar_operation stop
+
+		# We do not unlock the index directly here because this
+		# operation expects to potentially run in parallel with file
+		# deletions scheduled by revert_helper. We're done with the
+		# update index, so we close it, but actually unlocking the index
+		# and dealing with potential errors is deferred to the chord
+		# body that runs when all async operations are completed.
+		#
+		# (See after_chord in revert_helper.)
+
+		if {[catch {_close_updateindex $fd} err]} {
+			uplevel #0 $capture_error [list $err]
+		}
+
+		uplevel #0 $after
+
 		return
 	}
 
 	for {set i $batch} \
-		{$update_index_cp < $totalCnt && $i > 0} \
+		{$update_index_cp < $total_cnt && $i > 0} \
 		{incr i -1} {
-		set path [lindex $pathList $update_index_cp]
+		set path [lindex $path_list $update_index_cp]
 		incr update_index_cp
 		switch -glob -- [lindex $file_states($path) 0] {
 		U? {continue}
@@ -253,7 +285,7 @@ proc write_checkout_index {fd pathList totalCnt batch after} {
 		}
 	}
 
-	$::main_status update $update_index_cp $totalCnt
+	$status_bar_operation update $update_index_cp $total_cnt
 }
 
 proc unstage_helper {txt paths} {
@@ -261,7 +293,7 @@ proc unstage_helper {txt paths} {
 
 	if {![lock_index begin-update]} return
 
-	set pathList [list]
+	set path_list [list]
 	set after {}
 	foreach path $paths {
 		switch -glob -- [lindex $file_states($path) 0] {
@@ -269,19 +301,19 @@ proc unstage_helper {txt paths} {
 		M? -
 		T? -
 		D? {
-			lappend pathList $path
+			lappend path_list $path
 			if {$path eq $current_diff_path} {
 				set after {reshow_diff;}
 			}
 		}
 		}
 	}
-	if {$pathList eq {}} {
+	if {$path_list eq {}} {
 		unlock_index
 	} else {
 		update_indexinfo \
 			$txt \
-			$pathList \
+			$path_list \
 			[concat $after [list ui_ready]]
 	}
 }
@@ -305,7 +337,7 @@ proc add_helper {txt paths} {
 
 	if {![lock_index begin-update]} return
 
-	set pathList [list]
+	set path_list [list]
 	set after {}
 	foreach path $paths {
 		switch -glob -- [lindex $file_states($path) 0] {
@@ -321,19 +353,19 @@ proc add_helper {txt paths} {
 		?M -
 		?D -
 		?T {
-			lappend pathList $path
+			lappend path_list $path
 			if {$path eq $current_diff_path} {
 				set after {reshow_diff;}
 			}
 		}
 		}
 	}
-	if {$pathList eq {}} {
+	if {$path_list eq {}} {
 		unlock_index
 	} else {
 		update_index \
 			$txt \
-			$pathList \
+			$path_list \
 			[concat $after {ui_status [mc "Ready to commit."]}]
 	}
 }
@@ -388,66 +420,303 @@ proc do_add_all {} {
 	add_helper [mc "Adding all changed files"] $paths
 }
 
+# Copied from TclLib package "lambda".
+proc lambda {arguments body args} {
+	return [list ::apply [list $arguments $body] {*}$args]
+}
+
 proc revert_helper {txt paths} {
 	global file_states current_diff_path
 
 	if {![lock_index begin-update]} return
 
-	set pathList [list]
-	set after {}
+	# Common "after" functionality that waits until multiple asynchronous
+	# operations are complete (by waiting for them to activate their notes
+	# on the chord).
+	#
+	# The asynchronous operations are each indicated below by a comment
+	# before the code block that starts the async operation.
+	set after_chord [SimpleChord::new {
+		if {[string trim $err] != ""} {
+			rescan_on_error $err
+		} else {
+			unlock_index
+			if {$should_reshow_diff} { reshow_diff }
+			ui_ready
+		}
+	}]
+
+	$after_chord eval { set should_reshow_diff 0 }
+
+	# This function captures an error for processing when after_chord is
+	# completed. (The chord is curried into the lambda function.)
+	set capture_error [lambda \
+		{chord error} \
+		{ $chord eval [list set err $error] } \
+		$after_chord]
+
+	# We don't know how many notes we're going to create (it's dynamic based
+	# on conditional paths below), so create a common note that will delay
+	# the chord's completion until we activate it, and then activate it
+	# after all the other notes have been created.
+	set after_common_note [$after_chord add_note]
+
+	set path_list [list]
+	set untracked_list [list]
+
 	foreach path $paths {
 		switch -glob -- [lindex $file_states($path) 0] {
 		U? {continue}
+		?O {
+			lappend untracked_list $path
+		}
 		?M -
 		?T -
 		?D {
-			lappend pathList $path
+			lappend path_list $path
 			if {$path eq $current_diff_path} {
-				set after {reshow_diff;}
+				$after_chord eval { set should_reshow_diff 1 }
 			}
 		}
 		}
 	}
 
+	set path_cnt [llength $path_list]
+	set untracked_cnt [llength $untracked_list]
+
+	# Asynchronous operation: revert changes by checking them out afresh
+	# from the index.
+	if {$path_cnt > 0} {
+		# Split question between singular and plural cases, because
+		# such distinction is needed in some languages. Previously, the
+		# code used "Revert changes in" for both, but that can't work
+		# in languages where 'in' must be combined with word from
+		# rest of string (in different way for both cases of course).
+		#
+		# FIXME: Unfortunately, even that isn't enough in some languages
+		# as they have quite complex plural-form rules. Unfortunately,
+		# msgcat doesn't seem to support that kind of string
+		# translation.
+		#
+		if {$path_cnt == 1} {
+			set query [mc \
+				"Revert changes in file %s?" \
+				[short_path [lindex $path_list]] \
+				]
+		} else {
+			set query [mc \
+				"Revert changes in these %i files?" \
+				$path_cnt]
+		}
 
-	# Split question between singular and plural cases, because
-	# such distinction is needed in some languages. Previously, the
-	# code used "Revert changes in" for both, but that can't work
-	# in languages where 'in' must be combined with word from
-	# rest of string (in different way for both cases of course).
-	#
-	# FIXME: Unfortunately, even that isn't enough in some languages
-	# as they have quite complex plural-form rules. Unfortunately,
-	# msgcat doesn't seem to support that kind of string translation.
-	#
-	set n [llength $pathList]
-	if {$n == 0} {
-		unlock_index
-		return
-	} elseif {$n == 1} {
-		set query [mc "Revert changes in file %s?" [short_path [lindex $pathList]]]
-	} else {
-		set query [mc "Revert changes in these %i files?" $n]
+		set reply [tk_dialog \
+			.confirm_revert \
+			"[appname] ([reponame])" \
+			"$query
+
+[mc "Any unstaged changes will be permanently lost by the revert."]" \
+			question \
+			1 \
+			[mc "Do Nothing"] \
+			[mc "Revert Changes"] \
+			]
+
+		if {$reply == 1} {
+			set note [$after_chord add_note]
+			checkout_index \
+				$txt \
+				$path_list \
+				[list $note activate] \
+				$capture_error
+		}
 	}
 
-	set reply [tk_dialog \
-		.confirm_revert \
-		"[appname] ([reponame])" \
-		"$query
+	# Asynchronous operation: Deletion of untracked files.
+	if {$untracked_cnt > 0} {
+		# Split question between singular and plural cases, because
+		# such distinction is needed in some languages.
+		#
+		# FIXME: Unfortunately, even that isn't enough in some languages
+		# as they have quite complex plural-form rules. Unfortunately,
+		# msgcat doesn't seem to support that kind of string
+		# translation.
+		#
+		if {$untracked_cnt == 1} {
+			set query [mc \
+				"Delete untracked file %s?" \
+				[short_path [lindex $untracked_list]] \
+				]
+		} else {
+			set query [mc \
+				"Delete these %i untracked files?" \
+				$untracked_cnt \
+				]
+		}
 
-[mc "Any unstaged changes will be permanently lost by the revert."]" \
-		question \
-		1 \
-		[mc "Do Nothing"] \
-		[mc "Revert Changes"] \
-		]
-	if {$reply == 1} {
-		checkout_index \
-			$txt \
-			$pathList \
-			[concat $after [list ui_ready]]
+		set reply [tk_dialog \
+			.confirm_revert \
+			"[appname] ([reponame])" \
+			"$query
+
+[mc "Files will be permanently deleted."]" \
+			question \
+			1 \
+			[mc "Do Nothing"] \
+			[mc "Delete Files"] \
+			]
+
+		if {$reply == 1} {
+			$after_chord eval { set should_reshow_diff 1 }
+
+			set note [$after_chord add_note]
+			delete_files $untracked_list [list $note activate]
+		}
+	}
+
+	# Activate the common note. If no other notes were created, this
+	# completes the chord. If other notes were created, then this common
+	# note prevents a race condition where the chord might complete early.
+	$after_common_note activate
+}
+
+# Delete all of the specified files, performing deletion in batches to allow the
+# UI to remain responsive and updated.
+proc delete_files {path_list after} {
+	# Enable progress bar status updates
+	set status_bar_operation [$::main_status \
+		start \
+		[mc "Deleting"] \
+		[mc "files"]]
+
+	set path_index 0
+	set deletion_errors [list]
+	set batch_size 50
+
+	delete_helper \
+		$path_list \
+		$path_index \
+		$deletion_errors \
+		$batch_size \
+		$status_bar_operation \
+		$after
+}
+
+# Helper function to delete a list of files in batches. Each call deletes one
+# batch of files, and then schedules a call for the next batch after any UI
+# messages have been processed.
+proc delete_helper {path_list path_index deletion_errors batch_size \
+	status_bar_operation after} {
+	global file_states
+
+	set path_cnt [llength $path_list]
+
+	set batch_remaining $batch_size
+
+	while {$batch_remaining > 0} {
+		if {$path_index >= $path_cnt} { break }
+
+		set path [lindex $path_list $path_index]
+
+		set deletion_failed [catch {file delete -- $path} deletion_error]
+
+		if {$deletion_failed} {
+			lappend deletion_errors [list "$deletion_error"]
+		} else {
+			remove_empty_directories [file dirname $path]
+
+			# Don't assume the deletion worked. Remove the file from
+			# the UI, but only if it no longer exists.
+			if {![path_exists $path]} {
+				unset file_states($path)
+				display_file $path __
+			}
+		}
+
+		incr path_index 1
+		incr batch_remaining -1
+	}
+
+	# Update the progress bar to indicate that this batch has been
+	# completed. The update will be visible when this procedure returns
+	# and allows the UI thread to process messages.
+	$status_bar_operation update $path_index $path_cnt
+
+	if {$path_index < $path_cnt} {
+		# The Tcler's Wiki lists this as the best practice for keeping
+		# a UI active and processing messages during a long-running
+		# operation.
+
+		after idle [list after 0 [list \
+			delete_helper \
+			$path_list \
+			$path_index \
+			$deletion_errors \
+			$batch_size \
+			$status_bar_operation \
+			$after
+			]]
 	} else {
-		unlock_index
+		# Finish the status bar operation.
+		$status_bar_operation stop
+
+		# Report error, if any, based on how many deletions failed.
+		set deletion_error_cnt [llength $deletion_errors]
+
+		if {($deletion_error_cnt > 0)
+		 && ($deletion_error_cnt <= [MAX_VERBOSE_FILES_IN_DELETION_ERROR])} {
+			set error_text [mc "Encountered errors deleting files:\n"]
+
+			foreach deletion_error $deletion_errors {
+				append error_text "* [lindex $deletion_error 0]\n"
+			}
+
+			error_popup $error_text
+		} elseif {$deletion_error_cnt == $path_cnt} {
+			error_popup [mc \
+				"None of the %d selected files could be deleted." \
+				$path_cnt \
+				]
+		} elseif {$deletion_error_cnt > 1} {
+			error_popup [mc \
+				"%d of the %d selected files could not be deleted." \
+				$deletion_error_cnt \
+				$path_cnt \
+				]
+		}
+
+		uplevel #0 $after
+	}
+}
+
+proc MAX_VERBOSE_FILES_IN_DELETION_ERROR {} { return 10; }
+
+# This function is from the TCL documentation:
+#
+#   https://wiki.tcl-lang.org/page/file+exists
+#
+# [file exists] returns false if the path does exist but is a symlink to a path
+# that doesn't exist. This proc returns true if the path exists, regardless of
+# whether it is a symlink and whether it is broken.
+proc path_exists {name} {
+	expr {![catch {file lstat $name finfo}]}
+}
+
+# Remove as many empty directories as we can starting at the specified path,
+# walking up the directory tree. If we encounter a directory that is not
+# empty, or if a directory deletion fails, then we stop the operation and
+# return to the caller. Even if this procedure fails to delete any
+# directories at all, it does not report failure.
+proc remove_empty_directories {directory_path} {
+	set parent_path [file dirname $directory_path]
+
+	while {$parent_path != $directory_path} {
+		set contents [glob -nocomplain -dir $directory_path *]
+
+		if {[llength $contents] > 0} { break }
+		if {[catch {file delete -- $directory_path}]} { break }
+
+		set directory_path $parent_path
+		set parent_path [file dirname $directory_path]
 	}
 }
 
@@ -466,19 +735,19 @@ proc do_revert_selection {} {
 }
 
 proc do_select_commit_type {} {
-	global commit_type selected_commit_type
+	global commit_type commit_type_is_amend
 
-	if {$selected_commit_type eq {new}
+	if {$commit_type_is_amend == 0
 		&& [string match amend* $commit_type]} {
 		create_new_commit
-	} elseif {$selected_commit_type eq {amend}
+	} elseif {$commit_type_is_amend == 1
 		&& ![string match amend* $commit_type]} {
 		load_last_commit
 
 		# The amend request was rejected...
 		#
 		if {![string match amend* $commit_type]} {
-			set selected_commit_type new
+			set commit_type_is_amend 0
 		}
 	}
 }
diff --git a/third_party/git/git-gui/lib/merge.tcl b/third_party/git/git-gui/lib/merge.tcl
index 9f253db5b37e..664803cf3fd1 100644
--- a/third_party/git/git-gui/lib/merge.tcl
+++ b/third_party/git/git-gui/lib/merge.tcl
@@ -241,23 +241,27 @@ Continue with resetting the current changes?"]
 	if {[ask_popup $op_question] eq {yes}} {
 		set fd [git_read --stderr read-tree --reset -u -v HEAD]
 		fconfigure $fd -blocking 0 -translation binary
-		fileevent $fd readable [namespace code [list _reset_wait $fd]]
-		$::main_status start [mc "Aborting"] [mc "files reset"]
+		set status_bar_operation [$::main_status \
+			start \
+			[mc "Aborting"] \
+			[mc "files reset"]]
+		fileevent $fd readable [namespace code [list \
+			_reset_wait $fd $status_bar_operation]]
 	} else {
 		unlock_index
 	}
 }
 
-proc _reset_wait {fd} {
+proc _reset_wait {fd status_bar_operation} {
 	global ui_comm
 
-	$::main_status update_meter [read $fd]
+	$status_bar_operation update_meter [read $fd]
 
 	fconfigure $fd -blocking 1
 	if {[eof $fd]} {
 		set fail [catch {close $fd} err]
-		$::main_status stop
 		unlock_index
+		$status_bar_operation stop
 
 		$ui_comm delete 0.0 end
 		$ui_comm edit modified false
diff --git a/third_party/git/git-gui/lib/status_bar.tcl b/third_party/git/git-gui/lib/status_bar.tcl
index 02111a1742f9..d32b14142ff8 100644
--- a/third_party/git/git-gui/lib/status_bar.tcl
+++ b/third_party/git/git-gui/lib/status_bar.tcl
@@ -1,16 +1,42 @@
 # git-gui status bar mega-widget
 # Copyright (C) 2007 Shawn Pearce
 
+# The status_bar class manages the entire status bar. It is possible for
+# multiple overlapping asynchronous operations to want to display status
+# simultaneously. Each one receives a status_bar_operation when it calls the
+# start method, and the status bar combines all active operations into the
+# line of text it displays. Most of the time, there will be at most one
+# ongoing operation.
+#
+# Note that the entire status bar can be either in single-line or two-line
+# mode, depending on the constructor. Multiple active operations are only
+# supported for single-line status bars.
+
 class status_bar {
 
+field allow_multiple ; # configured at construction
+
 field w         ; # our own window path
 field w_l       ; # text widget we draw messages into
 field w_c       ; # canvas we draw a progress bar into
 field c_pack    ; # script to pack the canvas with
-field status  {}; # single line of text we show
-field prefix  {}; # text we format into status
-field units   {}; # unit of progress
-field meter   {}; # current core git progress meter (if active)
+
+field baseline_text   ; # text to show if there are no operations
+field status_bar_text ; # combined text for all operations
+
+field operations ; # list of current ongoing operations
+
+# The status bar can display a progress bar, updated when consumers call the
+# update method on their status_bar_operation. When there are multiple
+# operations, the status bar shows the combined status of all operations.
+#
+# When an overlapping operation completes, the progress bar is going to
+# abruptly have one fewer operation in the calculation, causing a discontinuity.
+# Therefore, whenever an operation completes, if it is not the last operation,
+# this counter is increased, and the progress bar is calculated as though there
+# were still another operation at 100%. When the last operation completes, this
+# is reset to 0.
+field completed_operation_count
 
 constructor new {path} {
 	global use_ttk NS
@@ -18,12 +44,19 @@ constructor new {path} {
 	set w_l $w.l
 	set w_c $w.c
 
+	# Standard single-line status bar: Permit overlapping operations
+	set allow_multiple 1
+
+	set baseline_text ""
+	set operations [list]
+	set completed_operation_count 0
+
 	${NS}::frame $w
 	if {!$use_ttk} {
 		$w configure -borderwidth 1 -relief sunken
 	}
 	${NS}::label $w_l \
-		-textvariable @status \
+		-textvariable @status_bar_text \
 		-anchor w \
 		-justify left
 	pack $w_l -side left
@@ -44,9 +77,16 @@ constructor two_line {path} {
 	set w_l $w.l
 	set w_c $w.c
 
+	# Two-line status bar: Only one ongoing operation permitted.
+	set allow_multiple 0
+
+	set baseline_text ""
+	set operations [list]
+	set completed_operation_count 0
+
 	${NS}::frame $w
 	${NS}::label $w_l \
-		-textvariable @status \
+		-textvariable @status_bar_text \
 		-anchor w \
 		-justify left
 	pack $w_l -anchor w -fill x
@@ -56,7 +96,7 @@ constructor two_line {path} {
 	return $this
 }
 
-method start {msg uds} {
+method ensure_canvas {} {
 	if {[winfo exists $w_c]} {
 		$w_c coords bar 0 0 0 20
 	} else {
@@ -68,31 +108,170 @@ method start {msg uds} {
 		$w_c create rectangle 0 0 0 20 -tags bar -fill navy
 		eval $c_pack
 	}
+}
+
+method show {msg} {
+	$this ensure_canvas
+	set baseline_text $msg
+	$this refresh
+}
+
+method start {msg {uds {}}} {
+	set baseline_text ""
+
+	if {!$allow_multiple && [llength $operations]} {
+		return [lindex $operations 0]
+	}
+
+	$this ensure_canvas
+
+	set operation [status_bar_operation::new $this $msg $uds]
+
+	lappend operations $operation
+
+	$this refresh
+
+	return $operation
+}
+
+method refresh {} {
+	set new_text ""
+
+	set total [expr $completed_operation_count * 100]
+	set have $total
+
+	foreach operation $operations {
+		if {$new_text != ""} {
+			append new_text " / "
+		}
+
+		append new_text [$operation get_status]
+
+		set total [expr $total + 100]
+		set have [expr $have + [$operation get_progress]]
+	}
+
+	if {$new_text == ""} {
+		set new_text $baseline_text
+	}
+
+	set status_bar_text $new_text
+
+	if {[winfo exists $w_c]} {
+		set pixel_width 0
+		if {$have > 0} {
+			set pixel_width [expr {[winfo width $w_c] * $have / $total}]
+		}
+
+		$w_c coords bar 0 0 $pixel_width 20
+	}
+}
+
+method stop {operation stop_msg} {
+	set idx [lsearch $operations $operation]
+
+	if {$idx >= 0} {
+		set operations [lreplace $operations $idx $idx]
+		set completed_operation_count [expr \
+			$completed_operation_count + 1]
+
+		if {[llength $operations] == 0} {
+			set completed_operation_count 0
+
+			destroy $w_c
+			if {$stop_msg ne {}} {
+				set baseline_text $stop_msg
+			}
+		}
+
+		$this refresh
+	}
+}
+
+method stop_all {{stop_msg {}}} {
+	# This makes the operation's call to stop a no-op.
+	set operations_copy $operations
+	set operations [list]
+
+	foreach operation $operations_copy {
+		$operation stop
+	}
+
+	if {$stop_msg ne {}} {
+		set baseline_text $stop_msg
+	}
+
+	$this refresh
+}
+
+method _delete {current} {
+	if {$current eq $w} {
+		delete_this
+	}
+}
+
+}
+
+# The status_bar_operation class tracks a single consumer's ongoing status bar
+# activity, with the context that there are a few situations where multiple
+# overlapping asynchronous operations might want to display status information
+# simultaneously. Instances of status_bar_operation are created by calling
+# start on the status_bar, and when the caller is done with its stauts bar
+# operation, it calls stop on the operation.
+
+class status_bar_operation {
+
+field status_bar; # reference back to the status_bar that owns this object
+
+field is_active;
+
+field status   {}; # single line of text we show
+field progress {}; # current progress (0 to 100)
+field prefix   {}; # text we format into status
+field units    {}; # unit of progress
+field meter    {}; # current core git progress meter (if active)
+
+constructor new {owner msg uds} {
+	set status_bar $owner
 
 	set status $msg
+	set progress 0
 	set prefix $msg
 	set units  $uds
 	set meter  {}
+
+	set is_active 1
+
+	return $this
 }
 
+method get_is_active {} { return $is_active }
+method get_status {} { return $status }
+method get_progress {} { return $progress }
+
 method update {have total} {
-	set pdone 0
-	set cdone 0
+	if {!$is_active} { return }
+
+	set progress 0
+
 	if {$total > 0} {
-		set pdone [expr {100 * $have / $total}]
-		set cdone [expr {[winfo width $w_c] * $have / $total}]
+		set progress [expr {100 * $have / $total}]
 	}
 
 	set prec [string length [format %i $total]]
+
 	set status [mc "%s ... %*i of %*i %s (%3i%%)" \
 		$prefix \
 		$prec $have \
 		$prec $total \
-		$units $pdone]
-	$w_c coords bar 0 0 $cdone 20
+		$units $progress]
+
+	$status_bar refresh
 }
 
 method update_meter {buf} {
+	if {!$is_active} { return }
+
 	append meter $buf
 	set r [string last "\r" $meter]
 	if {$r == -1} {
@@ -109,23 +288,25 @@ method update_meter {buf} {
 	}
 }
 
-method stop {{msg {}}} {
-	destroy $w_c
-	if {$msg ne {}} {
-		set status $msg
+method stop {{stop_msg {}}} {
+	if {$is_active} {
+		set is_active 0
+		$status_bar stop $this $stop_msg
 	}
 }
 
-method show {msg {test {}}} {
-	if {$test eq {} || $status eq $test} {
-		set status $msg
-	}
+method restart {msg} {
+	if {!$is_active} { return }
+
+	set status $msg
+	set prefix $msg
+	set meter {}
+	$status_bar refresh
 }
 
-method _delete {current} {
-	if {$current eq $w} {
-		delete_this
-	}
+method _delete {} {
+	stop
+	delete_this
 }
 
 }