merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/t/t4063-diff-blobs.sh

@@ -0,0 +1,96 @@
+#!/bin/sh
+
+test_description='test direct comparison of blobs via git-diff'
+. ./test-lib.sh
+
+run_diff () {
+	# use full-index to make it easy to match the index line
+	git diff --full-index "$@" >diff
+}
+
+check_index () {
+	grep "^index $1\\.\\.$2" diff
+}
+
+check_mode () {
+	grep "^old mode $1" diff &&
+	grep "^new mode $2" diff
+}
+
+check_paths () {
+	grep "^diff --git a/$1 b/$2" diff
+}
+
+test_expect_success 'create some blobs' '
+	echo one >one &&
+	echo two >two &&
+	chmod +x two &&
+	git add . &&
+
+	# cover systems where modes are ignored
+	git update-index --chmod=+x two &&
+
+	git commit -m base &&
+
+	sha1_one=$(git rev-parse HEAD:one) &&
+	sha1_two=$(git rev-parse HEAD:two)
+'
+
+test_expect_success 'diff by sha1' '
+	run_diff $sha1_one $sha1_two
+'
+test_expect_success 'index of sha1 diff' '
+	check_index $sha1_one $sha1_two
+'
+test_expect_success 'sha1 diff uses arguments as paths' '
+	check_paths $sha1_one $sha1_two
+'
+test_expect_success 'sha1 diff has no mode change' '
+	! grep mode diff
+'
+
+test_expect_success 'diff by tree:path (run)' '
+	run_diff HEAD:one HEAD:two
+'
+test_expect_success 'index of tree:path diff' '
+	check_index $sha1_one $sha1_two
+'
+test_expect_success 'tree:path diff uses filenames as paths' '
+	check_paths one two
+'
+test_expect_success 'tree:path diff shows mode change' '
+	check_mode 100644 100755
+'
+
+test_expect_success 'diff by ranged tree:path' '
+	run_diff HEAD:one..HEAD:two
+'
+test_expect_success 'index of ranged tree:path diff' '
+	check_index $sha1_one $sha1_two
+'
+test_expect_success 'ranged tree:path diff uses filenames as paths' '
+	check_paths one two
+'
+test_expect_success 'ranged tree:path diff shows mode change' '
+	check_mode 100644 100755
+'
+
+test_expect_success 'diff blob against file' '
+	run_diff HEAD:one two
+'
+test_expect_success 'index of blob-file diff' '
+	check_index $sha1_one $sha1_two
+'
+test_expect_success 'blob-file diff uses filename as paths' '
+	check_paths one two
+'
+test_expect_success FILEMODE 'blob-file diff shows mode change' '
+	check_mode 100644 100755
+'
+
+test_expect_success 'blob-file diff prefers filename to sha1' '
+	run_diff $sha1_one two &&
+	check_paths two two
+'
+
+test_done