Merge branch 'gt/at-is-synonym-for-head-in-add-patch'

Teach "git checkout -p" and friends that "@" is a synonym for
"HEAD".

* gt/at-is-synonym-for-head-in-add-patch:
  add -p tests: remove PERL prerequisites
  add-patch: classify '@' as a synonym for 'HEAD'

Author: gitster

add-patch.c

@@ -1729,14 +1729,6 @@ int run_add_p(struct repository *r, enum add_p_mode mode,
 	if (mode == ADD_P_STASH)
 		s.mode = &patch_mode_stash;
 	else if (mode == ADD_P_RESET) {
-		/*
-		 * NEEDSWORK: Instead of comparing to the literal "HEAD",
-		 * compare the commit objects instead so that other ways of
-		 * saying the same thing (such as "@") are also handled
-		 * appropriately.
-		 *
-		 * This applies to the cases below too.
-		 */
 		if (!revision || !strcmp(revision, "HEAD"))
 			s.mode = &patch_mode_reset_head;
 		else

builtin/checkout.c

@@ -1224,7 +1224,9 @@ static void setup_new_branch_info_and_source_tree(
 	struct tree **source_tree = &opts->source_tree;
 	struct object_id branch_rev;
 
-	new_branch_info->name = xstrdup(arg);
+	/* treat '@' as a shortcut for 'HEAD' */
+	new_branch_info->name = !strcmp(arg, "@") ? xstrdup("HEAD") :
+						    xstrdup(arg);
 	setup_branch_path(new_branch_info);
 
 	if (!check_refname_format(new_branch_info->path, 0) &&

builtin/reset.c

@@ -281,7 +281,9 @@ static void parse_args(struct pathspec *pathspec,
 			verify_filename(prefix, argv[0], 1);
 		}
 	}
-	*rev_ret = rev;
+
+	/* treat '@' as a shortcut for 'HEAD' */
+	*rev_ret = !strcmp("@", rev) ? "HEAD" : rev;
 
 	parse_pathspec(pathspec, 0,
 		       PATHSPEC_PREFER_FULL |

t/t2016-checkout-patch.sh

@@ -38,26 +38,32 @@ test_expect_success 'git checkout -p with staged changes' '
 	verify_state dir/foo index index
 '
 
-test_expect_success 'git checkout -p HEAD with NO staged changes: abort' '
-	set_and_save_state dir/foo work head &&
-	test_write_lines n y n | git checkout -p HEAD &&
-	verify_saved_state bar &&
-	verify_saved_state dir/foo
-'
-
-test_expect_success 'git checkout -p HEAD with NO staged changes: apply' '
-	test_write_lines n y y | git checkout -p HEAD &&
-	verify_saved_state bar &&
-	verify_state dir/foo head head
-'
-
-test_expect_success 'git checkout -p HEAD with change already staged' '
-	set_state dir/foo index index &&
-	# the third n is to get out in case it mistakenly does not apply
-	test_write_lines n y n | git checkout -p HEAD &&
-	verify_saved_state bar &&
-	verify_state dir/foo head head
-'
+for opt in "HEAD" "@"
+do
+	test_expect_success "git checkout -p $opt with NO staged changes: abort" '
+		set_and_save_state dir/foo work head &&
+		test_write_lines n y n | git checkout -p $opt >output &&
+		verify_saved_state bar &&
+		verify_saved_state dir/foo &&
+		test_grep "Discard" output
+	'
+
+	test_expect_success "git checkout -p $opt with NO staged changes: apply" '
+		test_write_lines n y y | git checkout -p $opt >output &&
+		verify_saved_state bar &&
+		verify_state dir/foo head head &&
+		test_grep "Discard" output
+	'
+
+	test_expect_success "git checkout -p $opt with change already staged" '
+		set_state dir/foo index index &&
+		# the third n is to get out in case it mistakenly does not apply
+		test_write_lines n y n | git checkout -p $opt >output &&
+		verify_saved_state bar &&
+		verify_state dir/foo head head &&
+		test_grep "Discard" output
+	'
+done
 
 test_expect_success 'git checkout -p HEAD^...' '
 	# the third n is to get out in case it mistakenly does not apply

t/t2020-checkout-detach.sh

@@ -45,6 +45,18 @@ test_expect_success 'checkout branch does not detach' '
 	check_not_detached
 '
 
+for opt in "HEAD" "@"
+do
+	test_expect_success "checkout $opt no-op/don't detach" '
+		reset &&
+		cat .git/HEAD >expect &&
+		git checkout $opt &&
+		cat .git/HEAD >actual &&
+		check_not_detached &&
+		test_cmp expect actual
+	'
+done
+
 test_expect_success 'checkout tag detaches' '
 	reset &&
 	git checkout tag &&

t/t2024-checkout-dwim.sh

@@ -113,7 +113,7 @@ test_expect_success 'checkout of branch from multiple remotes fails with advice'
 	test_grep ! "^hint: " stderr
 '
 
-test_expect_success PERL 'checkout -p with multiple remotes does not print advice' '
+test_expect_success 'checkout -p with multiple remotes does not print advice' '
 	git checkout -B main &&
 	test_might_fail git branch -D foo &&
 

t/t2071-restore-patch.sh

@@ -4,7 +4,7 @@ test_description='git restore --patch'
 
 . ./lib-patch-mode.sh
 
-test_expect_success PERL 'setup' '
+test_expect_success 'setup' '
 	mkdir dir &&
 	echo parent >dir/foo &&
 	echo dummy >bar &&
@@ -16,59 +16,63 @@ test_expect_success PERL 'setup' '
 	save_head
 '
 
-test_expect_success PERL 'restore -p without pathspec is fine' '
+test_expect_success 'restore -p without pathspec is fine' '
 	echo q >cmd &&
 	git restore -p <cmd
 '
 
 # note: bar sorts before dir/foo, so the first 'n' is always to skip 'bar'
 
-test_expect_success PERL 'saying "n" does nothing' '
+test_expect_success 'saying "n" does nothing' '
 	set_and_save_state dir/foo work head &&
 	test_write_lines n n | git restore -p &&
 	verify_saved_state bar &&
 	verify_saved_state dir/foo
 '
 
-test_expect_success PERL 'git restore -p' '
+test_expect_success 'git restore -p' '
 	set_and_save_state dir/foo work head &&
 	test_write_lines n y | git restore -p &&
 	verify_saved_state bar &&
 	verify_state dir/foo head head
 '
 
-test_expect_success PERL 'git restore -p with staged changes' '
+test_expect_success 'git restore -p with staged changes' '
 	set_state dir/foo work index &&
 	test_write_lines n y | git restore -p &&
 	verify_saved_state bar &&
 	verify_state dir/foo index index
 '
 
-test_expect_success PERL 'git restore -p --source=HEAD' '
-	set_state dir/foo work index &&
-	# the third n is to get out in case it mistakenly does not apply
-	test_write_lines n y n | git restore -p --source=HEAD &&
-	verify_saved_state bar &&
-	verify_state dir/foo head index
-'
-
-test_expect_success PERL 'git restore -p --source=HEAD^' '
+for opt in "HEAD" "@"
+do
+	test_expect_success "git restore -p --source=$opt" '
+		set_state dir/foo work index &&
+		# the third n is to get out in case it mistakenly does not apply
+		test_write_lines n y n | git restore -p --source=$opt >output &&
+		verify_saved_state bar &&
+		verify_state dir/foo head index &&
+		test_grep "Discard" output
+	'
+done
+
+test_expect_success 'git restore -p --source=HEAD^' '
 	set_state dir/foo work index &&
 	# the third n is to get out in case it mistakenly does not apply
 	test_write_lines n y n | git restore -p --source=HEAD^ &&
 	verify_saved_state bar &&
 	verify_state dir/foo parent index
 '
 
-test_expect_success PERL 'git restore -p --source=HEAD^...' '
+test_expect_success 'git restore -p --source=HEAD^...' '
 	set_state dir/foo work index &&
 	# the third n is to get out in case it mistakenly does not apply
 	test_write_lines n y n | git restore -p --source=HEAD^... &&
 	verify_saved_state bar &&
 	verify_state dir/foo parent index
 '
 
-test_expect_success PERL 'git restore -p handles deletion' '
+test_expect_success 'git restore -p handles deletion' '
 	set_state dir/foo work index &&
 	rm dir/foo &&
 	test_write_lines n y | git restore -p &&
@@ -81,37 +85,37 @@ test_expect_success PERL 'git restore -p handles deletion' '
 # dir/foo.  There's always an extra 'n' to reject edits to dir/foo in
 # the failure case (and thus get out of the loop).
 
-test_expect_success PERL 'path limiting works: dir' '
+test_expect_success 'path limiting works: dir' '
 	set_state dir/foo work head &&
 	test_write_lines y n | git restore -p dir &&
 	verify_saved_state bar &&
 	verify_state dir/foo head head
 '
 
-test_expect_success PERL 'path limiting works: -- dir' '
+test_expect_success 'path limiting works: -- dir' '
 	set_state dir/foo work head &&
 	test_write_lines y n | git restore -p -- dir &&
 	verify_saved_state bar &&
 	verify_state dir/foo head head
 '
 
-test_expect_success PERL 'path limiting works: HEAD^ -- dir' '
+test_expect_success 'path limiting works: HEAD^ -- dir' '
 	set_state dir/foo work head &&
 	# the third n is to get out in case it mistakenly does not apply
 	test_write_lines y n n | git restore -p --source=HEAD^ -- dir &&
 	verify_saved_state bar &&
 	verify_state dir/foo parent head
 '
 
-test_expect_success PERL 'path limiting works: foo inside dir' '
+test_expect_success 'path limiting works: foo inside dir' '
 	set_state dir/foo work head &&
 	# the third n is to get out in case it mistakenly does not apply
 	test_write_lines y n n | (cd dir && git restore -p foo) &&
 	verify_saved_state bar &&
 	verify_state dir/foo head head
 '
 
-test_expect_success PERL 'none of this moved HEAD' '
+test_expect_success 'none of this moved HEAD' '
 	verify_saved_head
 '
 

t/t3904-stash-patch.sh

@@ -3,12 +3,6 @@
 test_description='stash -p'
 . ./lib-patch-mode.sh
 
-if ! test_have_prereq PERL
-then
-	skip_all='skipping stash -p tests, perl not available'
-	test_done
-fi
-
 test_expect_success 'setup' '
 	mkdir dir &&
 	echo parent > dir/foo &&

t/t7105-reset-patch.sh

@@ -5,7 +5,7 @@ test_description='git reset --patch'
 TEST_PASSES_SANITIZE_LEAK=true
 . ./lib-patch-mode.sh
 
-test_expect_success PERL 'setup' '
+test_expect_success 'setup' '
 	mkdir dir &&
 	echo parent > dir/foo &&
 	echo dummy > bar &&
@@ -19,42 +19,46 @@ test_expect_success PERL 'setup' '
 
 # note: bar sorts before foo, so the first 'n' is always to skip 'bar'
 
-test_expect_success PERL 'saying "n" does nothing' '
+test_expect_success 'saying "n" does nothing' '
 	set_and_save_state dir/foo work work &&
 	test_write_lines n n | git reset -p &&
 	verify_saved_state dir/foo &&
 	verify_saved_state bar
 '
 
-test_expect_success PERL 'git reset -p' '
-	test_write_lines n y | git reset -p >output &&
-	verify_state dir/foo work head &&
-	verify_saved_state bar &&
-	test_grep "Unstage" output
-'
-
-test_expect_success PERL 'git reset -p HEAD^' '
+for opt in "HEAD" "@" ""
+do
+	test_expect_success "git reset -p $opt" '
+		set_and_save_state dir/foo work work &&
+		test_write_lines n y | git reset -p $opt >output &&
+		verify_state dir/foo work head &&
+		verify_saved_state bar &&
+		test_grep "Unstage" output
+	'
+done
+
+test_expect_success 'git reset -p HEAD^' '
 	test_write_lines n y | git reset -p HEAD^ >output &&
 	verify_state dir/foo work parent &&
 	verify_saved_state bar &&
 	test_grep "Apply" output
 '
 
-test_expect_success PERL 'git reset -p HEAD^^{tree}' '
+test_expect_success 'git reset -p HEAD^^{tree}' '
 	test_write_lines n y | git reset -p HEAD^^{tree} >output &&
 	verify_state dir/foo work parent &&
 	verify_saved_state bar &&
 	test_grep "Apply" output
 '
 
-test_expect_success PERL 'git reset -p HEAD^:dir/foo (blob fails)' '
+test_expect_success 'git reset -p HEAD^:dir/foo (blob fails)' '
 	set_and_save_state dir/foo work work &&
 	test_must_fail git reset -p HEAD^:dir/foo &&
 	verify_saved_state dir/foo &&
 	verify_saved_state bar
 '
 
-test_expect_success PERL 'git reset -p aaaaaaaa (unknown fails)' '
+test_expect_success 'git reset -p aaaaaaaa (unknown fails)' '
 	set_and_save_state dir/foo work work &&
 	test_must_fail git reset -p aaaaaaaa &&
 	verify_saved_state dir/foo &&
@@ -66,27 +70,27 @@ test_expect_success PERL 'git reset -p aaaaaaaa (unknown fails)' '
 # dir/foo.  There's always an extra 'n' to reject edits to dir/foo in
 # the failure case (and thus get out of the loop).
 
-test_expect_success PERL 'git reset -p dir' '
+test_expect_success 'git reset -p dir' '
 	set_state dir/foo work work &&
 	test_write_lines y n | git reset -p dir &&
 	verify_state dir/foo work head &&
 	verify_saved_state bar
 '
 
-test_expect_success PERL 'git reset -p -- foo (inside dir)' '
+test_expect_success 'git reset -p -- foo (inside dir)' '
 	set_state dir/foo work work &&
 	test_write_lines y n | (cd dir && git reset -p -- foo) &&
 	verify_state dir/foo work head &&
 	verify_saved_state bar
 '
 
-test_expect_success PERL 'git reset -p HEAD^ -- dir' '
+test_expect_success 'git reset -p HEAD^ -- dir' '
 	test_write_lines y n | git reset -p HEAD^ -- dir &&
 	verify_state dir/foo work parent &&
 	verify_saved_state bar
 '
 
-test_expect_success PERL 'none of this moved HEAD' '
+test_expect_success 'none of this moved HEAD' '
 	verify_saved_head
 '
 

t/t7106-reset-unborn-branch.sh

@@ -34,7 +34,7 @@ test_expect_success 'reset $file' '
 	test_cmp expect actual
 '
 
-test_expect_success PERL 'reset -p' '
+test_expect_success 'reset -p' '
 	rm .git/index &&
 	git add a &&
 	echo y >yes &&