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, 22 insertions, 12 deletions

diff --git a/third_party/git/git-svn.perl b/third_party/git/git-svn.perl
index 050f2a36f414..58f5a7ac8f80 100755
--- a/third_party/git/git-svn.perl
+++ b/third_party/git/git-svn.perl
@@ -5,7 +5,8 @@ use 5.008;
 use warnings;
 use strict;
 use vars qw/	$AUTHOR $VERSION
-		$sha1 $sha1_short $_revision $_repository
+		$oid $oid_short $oid_length
+		$_revision $_repository
 		$_q $_authors $_authors_prog %users/;
 $AUTHOR = 'Eric Wong <normalperson@yhbt.net>';
 $VERSION = '@@GIT_VERSION@@';
@@ -103,14 +104,15 @@ sub _req_svn {
 	}
 }
 
-$sha1 = qr/[a-f\d]{40}/;
-$sha1_short = qr/[a-f\d]{4,40}/;
+$oid = qr/(?:[a-f\d]{40}(?:[a-f\d]{24})?)/;
+$oid_short = qr/[a-f\d]{4,64}/;
+$oid_length = 40;
 my ($_stdin, $_help, $_edit,
 	$_message, $_file, $_branch_dest,
 	$_template, $_shared,
 	$_version, $_fetch_all, $_no_rebase, $_fetch_parent,
 	$_before, $_after,
-	$_merge, $_strategy, $_preserve_merges, $_dry_run, $_parents, $_local,
+	$_merge, $_strategy, $_rebase_merges, $_dry_run, $_parents, $_local,
 	$_prefix, $_no_checkout, $_url, $_verbose,
 	$_commit_url, $_tag, $_merge_info, $_interactive, $_set_svn_props);
 
@@ -270,7 +272,8 @@ my %cmd = (
 			  'local|l' => \$_local,
 			  'fetch-all|all' => \$_fetch_all,
 			  'dry-run|n' => \$_dry_run,
-			  'preserve-merges|p' => \$_preserve_merges,
+			  'rebase-merges|p' => \$_rebase_merges,
+			  'preserve-merges|p' => \$_rebase_merges,
 			  %fc_opts } ],
 	'commit-diff' => [ \&cmd_commit_diff,
 	                   'Commit a diff between two trees',
@@ -497,6 +500,7 @@ sub do_git_init_db {
 		command_noisy('config', "$pfx.preserve-empty-dirs", 'true');
 		command_noisy('config', "$pfx.placeholder-filename", $$fname);
 	}
+	load_object_format();
 }
 
 sub init_subdir {
@@ -581,7 +585,7 @@ sub cmd_set_tree {
 		print "Reading from stdin...\n";
 		@commits = ();
 		while (<STDIN>) {
-			if (/\b($sha1_short)\b/o) {
+			if (/\b($oid_short)\b/o) {
 				unshift @commits, $1;
 			}
 		}
@@ -1054,7 +1058,7 @@ sub cmd_dcommit {
 					  'If you are attempting to commit ',
 					  "merges, try running:\n\t",
 					  'git rebase --interactive',
-					  '--preserve-merges ',
+					  '--rebase-merges ',
 					  $gs->refname,
 					  "\nBefore dcommitting";
 				}
@@ -1717,7 +1721,7 @@ sub rebase_cmd {
 	push @cmd, '-v' if $_verbose;
 	push @cmd, qw/--merge/ if $_merge;
 	push @cmd, "--strategy=$_strategy" if $_strategy;
-	push @cmd, "--preserve-merges" if $_preserve_merges;
+	push @cmd, "--rebase-merges" if $_rebase_merges;
 	@cmd;
 }
 
@@ -1830,7 +1834,7 @@ sub get_tree_from_treeish {
 	if ($type eq 'commit') {
 		$expected = (grep /^tree /, command(qw/cat-file commit/,
 		                                    $treeish))[0];
-		($expected) = ($expected =~ /^tree ($sha1)$/o);
+		($expected) = ($expected =~ /^tree ($oid)$/o);
 		die "Unable to get tree from $treeish\n" unless $expected;
 	} elsif ($type eq 'tree') {
 		$expected = $treeish;
@@ -1974,9 +1978,15 @@ sub read_git_config {
 			}
 		}
 	}
+	load_object_format();
 	delete @$opts{@config_only} if @config_only;
 }
 
+sub load_object_format {
+	chomp(my $hash = `git config --get extensions.objectformat`);
+	$::oid_length = 64 if $hash eq 'sha256';
+}
+
 sub extract_metadata {
 	my $id = shift or return (undef, undef, undef);
 	my ($url, $rev, $uuid) = ($id =~ /^\s*git-svn-id:\s+(.*)\@(\d+)
@@ -2005,10 +2015,10 @@ sub cmt_sha2rev_batch {
 		print $out $sha, "\n";
 
 		while (my $line = <$in>) {
-			if ($first && $line =~ /^[[:xdigit:]]{40}\smissing$/) {
+			if ($first && $line =~ /^$::oid\smissing$/) {
 				last;
 			} elsif ($first &&
-			       $line =~ /^[[:xdigit:]]{40}\scommit\s(\d+)$/) {
+			       $line =~ /^$::oid\scommit\s(\d+)$/) {
 				$first = 0;
 				$size = $1;
 				next;
@@ -2035,7 +2045,7 @@ sub working_head_info {
 	my $hash;
 	my %max;
 	while (<$fh>) {
-		if ( m{^commit ($::sha1)$} ) {
+		if ( m{^commit ($::oid)$} ) {
 			unshift @$refs, $hash if $hash and $refs;
 			$hash = $1;
 			next;