From bf68b116997a0471dfccf7dcced00eb7d8b66982 Mon Sep 17 00:00:00 2001 From: Kristoffer Haugsbakk Date: Wed, 17 Sep 2025 22:24:14 +0200 Subject: [PATCH] git: allow alias-shadowing deprecated builtins MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit git-whatchanged(1) is deprecated and you need to pass `--i-still-use-this` in order to force it to work as before. There are two affected users, or usages: 1. people who use the command in scripts; and 2. people who are used to using it interactively. For (1) the replacement is straightforward.[1] But people in (2) might like the name or be really used to typing it.[3] An obvious first thought is to suggest aliasing `whatchanged` to the git-log(1) equivalent.[1] But this doesn’t work and is awkward since you cannot shadow builtins via aliases. Now you are left in an uncomfortable limbo; your alias won’t work until the command is removed for good. Let’s lift this limitation by allowing *deprecated* builtins to be shadowed by aliases. The only observed demand for aliasing has been for git-whatchanged(1), not for git-pack-redundant(1). But let’s be consistent and treat all deprecated commands the same. [1]: git log --raw --no-merges With a minor caveat: you get different outputs if you happen to have empty commits (no changes)[2] [2]: https://lore.kernel.org/git/20250825085428.GA367101@coredump.intra.peff.net/ [3]: https://lore.kernel.org/git/BL3P221MB0449288C8B0FA448A227FD48833AA@BL3P221MB0449.NAMP221.PROD.OUTLOOK.COM/ Based-on-patch-by: Jeff King Signed-off-by: Kristoffer Haugsbakk Signed-off-by: Junio C Hamano --- Documentation/config/alias.adoc | 3 ++- git.c | 17 ++++++++++++++ t/t0014-alias.sh | 40 +++++++++++++++++++++++++++++++++ 3 files changed, 59 insertions(+), 1 deletion(-) diff --git a/Documentation/config/alias.adoc b/Documentation/config/alias.adoc index 2c5db0ad84..3c8fab3a95 100644 --- a/Documentation/config/alias.adoc +++ b/Documentation/config/alias.adoc @@ -3,7 +3,8 @@ alias.*:: after defining `alias.last = cat-file commit HEAD`, the invocation `git last` is equivalent to `git cat-file commit HEAD`. To avoid confusion and troubles with script usage, aliases that - hide existing Git commands are ignored. Arguments are split by + hide existing Git commands are ignored except for deprecated + commands. Arguments are split by spaces, the usual shell quoting and escaping are supported. A quote pair or a backslash can be used to quote them. + diff --git a/git.c b/git.c index ef1e7b205a..8c85da84c3 100644 --- a/git.c +++ b/git.c @@ -824,12 +824,29 @@ static void execv_dashed_external(const char **argv) exit(128); } +static int is_deprecated_command(const char *cmd) +{ + struct cmd_struct *builtin = get_builtin(cmd); + return builtin && (builtin->option & DEPRECATED); +} + static int run_argv(struct strvec *args) { int done_alias = 0; struct string_list expanded_aliases = STRING_LIST_INIT_DUP; while (1) { + /* + * Allow deprecated commands to be overridden by aliases. This + * creates a seamless path forward for people who want to keep + * using the name after it is gone, but want to skip the + * deprecation complaint in the meantime. + */ + if (is_deprecated_command(args->v[0]) && + handle_alias(args, &expanded_aliases)) { + done_alias = 1; + continue; + } /* * If we tried alias and futzed with our environment, * it no longer is safe to invoke builtins directly in diff --git a/t/t0014-alias.sh b/t/t0014-alias.sh index 854d59ec58..1b196ed9d6 100755 --- a/t/t0014-alias.sh +++ b/t/t0014-alias.sh @@ -27,6 +27,20 @@ test_expect_success 'looping aliases - internal execution' ' test_grep "^fatal: alias loop detected: expansion of" output ' +test_expect_success 'looping aliases - deprecated builtins' ' + test_config alias.whatchanged pack-redundant && + test_config alias.pack-redundant whatchanged && + cat >expect <<-EOF && + ${SQ}whatchanged${SQ} is aliased to ${SQ}pack-redundant${SQ} + ${SQ}pack-redundant${SQ} is aliased to ${SQ}whatchanged${SQ} + fatal: alias loop detected: expansion of ${SQ}whatchanged${SQ} does not terminate: + whatchanged <== + pack-redundant ==> + EOF + test_must_fail git whatchanged -h 2>actual && + test_cmp expect actual +' + # This test is disabled until external loops are fixed, because would block # the test suite for a full minute. # @@ -55,4 +69,30 @@ test_expect_success 'tracing a shell alias with arguments shows trace of prepare test_cmp expect actual ' +can_alias_deprecated_builtin () { + cmd="$1" && + # some git(1) commands will fail for `-h` (the case for + # git-status as of 2025-09-07) + test_might_fail git status -h >expect && + test_file_not_empty expect && + test_might_fail git -c alias."$cmd"=status "$cmd" -h >actual && + test_cmp expect actual +} + +test_expect_success 'can alias-shadow deprecated builtins' ' + for cmd in $(git --list-cmds=deprecated) + do + can_alias_deprecated_builtin "$cmd" || return 1 + done +' + +test_expect_success 'can alias-shadow via two deprecated builtins' ' + # some git(1) commands will fail... (see above) + test_might_fail git status -h >expect && + test_file_not_empty expect && + test_might_fail git -c alias.whatchanged=pack-redundant \ + -c alias.pack-redundant=status whatchanged -h >actual && + test_cmp expect actual +' + test_done -- 2.47.3