merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 99 insertions, 30 deletions

diff --git a/third_party/git/git-gui/lib/diff.tcl b/third_party/git/git-gui/lib/diff.tcl
index 68c4a6c736..871ad488c2 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
 }