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, 27 insertions, 1 deletions

diff --git a/third_party/git/perl/Git.pm b/third_party/git/perl/Git.pm
index 62c472e0ce41..10df990959e6 100644
--- a/third_party/git/perl/Git.pm
+++ b/third_party/git/perl/Git.pm
@@ -563,7 +563,7 @@ sub get_record {
 Query user C<PROMPT> and return answer from user.
 
 Honours GIT_ASKPASS and SSH_ASKPASS environment variables for querying
-the user. If no *_ASKPASS variable is set or an error occoured,
+the user. If no *_ASKPASS variable is set or an error occurred,
 the terminal is tried as a fallback.
 If C<ISPASSWORD> is set and true, the terminal disables echo.
 
@@ -723,6 +723,32 @@ sub config_int {
 	return scalar _config_common({'kind' => '--int'}, @_);
 }
 
+=item config_regexp ( RE )
+
+Retrieve the list of configuration key names matching the regular
+expression C<RE>. The return value is a list of strings matching
+this regex.
+
+=cut
+
+sub config_regexp {
+	my ($self, $regex) = _maybe_self(@_);
+	try {
+		my @cmd = ('config', '--name-only', '--get-regexp', $regex);
+		unshift @cmd, $self if $self;
+		my @matches = command(@cmd);
+		return @matches;
+	} catch Git::Error::Command with {
+		my $E = shift;
+		if ($E->value() == 1) {
+			my @matches = ();
+			return @matches;
+		} else {
+			throw $E;
+		}
+	};
+}
+
 # Common subroutine to implement bulk of what the config* family of methods
 # do. This currently wraps command('config') so it is not so fast.
 sub _config_common {