stash: remove the stash.useBuiltin setting

Remove the stash.useBuiltin setting which was added as an escape hatch
to disable the builtin version of stash first released with Git 2.22.

Carrying the legacy version is a maintenance burden, and has in fact
become out of date failing a test since the 2.23 release, without
anyone noticing until now.  So users would be getting a hint to fall
back to a potentially buggy version of the tool.

We used to shell out to git config to get the useBuiltin configuration
to avoid changing any global state before spawning legacy-stash.
However that is no longer necessary, so just use the 'git_config'
function to get the setting instead.

Similar to what we've done in d03ebd4 ("rebase: remove the
rebase.useBuiltin setting", 2019-03-18), where we remove the
corresponding setting for rebase, we leave the documentation in place,
so people can refer back to it when searching for it online, and so we
can refer to it in the commit message.

Signed-off-by: Thomas Gummerer <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: tgummerer

.gitignore

@@ -83,7 +83,6 @@
 /git-init-db
 /git-interpret-trailers
 /git-instaweb
-/git-legacy-stash
 /git-log
 /git-ls-files
 /git-ls-remote

Documentation/config/stash.txt

@@ -1,17 +1,9 @@
 stash.useBuiltin::
-       Set to `false` to use the legacy shell script implementation of
-       linkgit:git-stash[1]. Is `true` by default, which means use
-       the built-in rewrite of it in C.
-+
-The C rewrite is first included with Git version 2.22 (and Git for Windows
-version 2.19). This option serves as an escape hatch to re-enable the
-legacy version in case any bugs are found in the rewrite. This option and
-the shell script version of linkgit:git-stash[1] will be removed in some
-future release.
-+
-If you find some reason to set this option to `false`, other than
-one-off testing, you should report the behavior difference as a bug in
-Git (see https://git-scm.com/community for details).
+	Unused configuration variable.  Used in Git versions 2.22 to
+	2.26 as an escape hatch to enable the legacy shellscript
+	implementation of stash.  Now the built-in rewrite of it in C
+	is always used. Setting this will emit a warning, to alert any
+	remaining users that setting this now does nothing.
 
 stash.showPatch::
 	If this is set to true, the `git stash show` command without an

Makefile

@@ -609,7 +609,6 @@ SCRIPT_SH += git-merge-one-file.sh
 SCRIPT_SH += git-merge-resolve.sh
 SCRIPT_SH += git-mergetool.sh
 SCRIPT_SH += git-quiltimport.sh
-SCRIPT_SH += git-legacy-stash.sh
 SCRIPT_SH += git-request-pull.sh
 SCRIPT_SH += git-submodule.sh
 SCRIPT_SH += git-web--browse.sh

builtin/stash.c

@@ -701,6 +701,7 @@ static int list_stash(int argc, const char **argv, const char *prefix)
 
 static int show_stat = 1;
 static int show_patch;
+static int use_legacy_stash;
 
 static int git_stash_config(const char *var, const char *value, void *cb)
 {
@@ -712,6 +713,10 @@ static int git_stash_config(const char *var, const char *value, void *cb)
 		show_patch = git_config_bool(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "stash.usebuiltin")) {
+		use_legacy_stash = !git_config_bool(var, value);
+		return 0;
+	}
 	return git_diff_basic_config(var, value, cb);
 }
 
@@ -1524,29 +1529,6 @@ static int save_stash(int argc, const char **argv, const char *prefix)
 	return ret;
 }
 
-static int use_builtin_stash(void)
-{
-	struct child_process cp = CHILD_PROCESS_INIT;
-	struct strbuf out = STRBUF_INIT;
-	int ret, env = git_env_bool("GIT_TEST_STASH_USE_BUILTIN", -1);
-
-	if (env != -1)
-		return env;
-
-	argv_array_pushl(&cp.args,
-			 "config", "--bool", "stash.usebuiltin", NULL);
-	cp.git_cmd = 1;
-	if (capture_command(&cp, &out, 6)) {
-		strbuf_release(&out);
-		return 1;
-	}
-
-	strbuf_trim(&out);
-	ret = !strcmp("true", out.buf);
-	strbuf_release(&out);
-	return ret;
-}
-
 int cmd_stash(int argc, const char **argv, const char *prefix)
 {
 	int i = -1;
@@ -1558,22 +1540,13 @@ int cmd_stash(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	if (!use_builtin_stash()) {
-		const char *path = mkpath("%s/git-legacy-stash",
-					  git_exec_path());
-
-		if (sane_execvp(path, (char **)argv) < 0)
-			die_errno(_("could not exec %s"), path);
-		else
-			BUG("sane_execvp() returned???");
-	}
-
-	prefix = setup_git_directory();
-	trace_repo_setup(prefix);
-	setup_work_tree();
-
 	git_config(git_stash_config, NULL);
 
+	if (use_legacy_stash ||
+	    !git_env_bool("GIT_TEST_STASH_USE_BUILTIN", -1))
+		warning(_("the stash.useBuiltin support has been removed!\n"
+			  "See its entry in 'git help config' for details."));
+
 	argc = parse_options(argc, argv, prefix, options, git_stash_usage,
 			     PARSE_OPT_KEEP_UNKNOWN | PARSE_OPT_KEEP_DASHDASH);