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, 62 insertions, 0 deletions

diff --git a/third_party/git/t/t6405-merge-symlinks.sh b/third_party/git/t/t6405-merge-symlinks.sh
new file mode 100755
index 0000000000..6c0a90d044
--- /dev/null
+++ b/third_party/git/t/t6405-merge-symlinks.sh
@@ -0,0 +1,62 @@
+#!/bin/sh
+#
+# Copyright (c) 2007 Johannes Sixt
+#
+
+test_description='merging symlinks on filesystem w/o symlink support.
+
+This tests that git merge-recursive writes merge results as plain files
+if core.symlinks is false.'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	git config core.symlinks false &&
+	>file &&
+	git add file &&
+	git commit -m initial &&
+	git branch b-symlink &&
+	git branch b-file &&
+	l=$(printf file | git hash-object -t blob -w --stdin) &&
+	echo "120000 $l	symlink" | git update-index --index-info &&
+	git commit -m master &&
+	git checkout b-symlink &&
+	l=$(printf file-different | git hash-object -t blob -w --stdin) &&
+	echo "120000 $l	symlink" | git update-index --index-info &&
+	git commit -m b-symlink &&
+	git checkout b-file &&
+	echo plain-file >symlink &&
+	git add symlink &&
+	git commit -m b-file
+'
+
+test_expect_success 'merge master into b-symlink, which has a different symbolic link' '
+	git checkout b-symlink &&
+	test_must_fail git merge master
+'
+
+test_expect_success 'the merge result must be a file' '
+	test_path_is_file symlink
+'
+
+test_expect_success 'merge master into b-file, which has a file instead of a symbolic link' '
+	git reset --hard &&
+	git checkout b-file &&
+	test_must_fail git merge master
+'
+
+test_expect_success 'the merge result must be a file' '
+	test_path_is_file symlink
+'
+
+test_expect_success 'merge b-file, which has a file instead of a symbolic link, into master' '
+	git reset --hard &&
+	git checkout master &&
+	test_must_fail git merge b-file
+'
+
+test_expect_success 'the merge result must be a file' '
+	test_path_is_file symlink
+'
+
+test_done