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, 56 insertions, 0 deletions

diff --git a/third_party/git/t/t5411/common-functions.sh b/third_party/git/t/t5411/common-functions.sh
new file mode 100644
index 000000000000..6580bebd8e4b
--- /dev/null
+++ b/third_party/git/t/t5411/common-functions.sh
@@ -0,0 +1,56 @@
+# Create commits in <repo> and assign each commit's oid to shell variables
+# given in the arguments (A, B, and C). E.g.:
+#
+#     create_commits_in <repo> A B C
+#
+# NOTE: Never calling this function from a subshell since variable
+# assignments will disappear when subshell exits.
+create_commits_in () {
+	repo="$1" &&
+	if ! parent=$(git -C "$repo" rev-parse HEAD^{} --)
+	then
+		parent=
+	fi &&
+	T=$(git -C "$repo" write-tree) &&
+	shift &&
+	while test $# -gt 0
+	do
+		name=$1 &&
+		test_tick &&
+		if test -z "$parent"
+		then
+			oid=$(echo $name | git -C "$repo" commit-tree $T)
+		else
+			oid=$(echo $name | git -C "$repo" commit-tree -p $parent $T)
+		fi &&
+		eval $name=$oid &&
+		parent=$oid &&
+		shift ||
+		return 1
+	done &&
+	git -C "$repo" update-ref refs/heads/master $oid
+}
+
+# Format the output of git-push, git-show-ref and other commands to make a
+# user-friendly and stable text.  We can easily prepare the expect text
+# without having to worry about future changes of the commit ID and spaces
+# of the output.  Single quotes are replaced with double quotes, because
+# it is boring to prepare unquoted single quotes in expect text.  We also
+# remove some locale error messages, which break test if we turn on
+# `GIT_TEST_GETTEXT_POISON=true` in order to test unintentional translations
+# on plumbing commands.
+make_user_friendly_and_stable_output () {
+	sed \
+		-e "s/  *\$//" \
+		-e "s/   */ /g" \
+		-e "s/'/\"/g" \
+		-e "s/	/    /g" \
+		-e "s/$A/<COMMIT-A>/g" \
+		-e "s/$B/<COMMIT-B>/g" \
+		-e "s/$TAG/<TAG-v123>/g" \
+		-e "s/$ZERO_OID/<ZERO-OID>/g" \
+		-e "s/$(echo $A | cut -c1-7)[0-9a-f]*/<OID-A>/g" \
+		-e "s/$(echo $B | cut -c1-7)[0-9a-f]*/<OID-B>/g" \
+		-e "s#To $URL_PREFIX/upstream.git#To <URL/of/upstream.git>#" \
+		-e "/^error: / d"
+}