In trying to make some aliases more consistent in an internal tool, I
implemented both -h/--help in the underlying command for a shell
alias, and was a bit surprised when "git <alias> -h" worked but "git
<alias> --help" didn't.
In the "-h" case in git.c:handle_alias() we have a little check for
"-h" which pre-prints the "<alias> is aliased to..." line and then
continues to run the alias.
However in the "--help" case we fall into the logic that turns "git
cmd --help" into "git help cmd"
help.c contains a check to just print the alias mapping if called as
"git help <alias>", but if called as "git <alias> --help", will
redirect to the help of the aliased-command. Since a shell alias does
not have a 1:1 mapping with an internal command, the current check
prints the alias mapping and simply exits in that case (causing my
alias script "--help" command to never trigger).
I would propose that "--help" to a shell alias is passed through to
the underlying command. This way you can write aliases that act more
like the other git commands.
To do this, we make "--help" work the same as "-h" for shell aliases.
In git.c where we check for the "--help" argument, for shell aliases
we print the aliased command as "-h" does, but then shortcut the
rewriting to "git help", so the aliased command will run and not be
sent to "git help".
Since "git <alias> --help" will not be re-written for shell aliases,
"git help" can now assume that it is being asked to help on a
git-command alias. Thus we can remove the "is this a rewritten shell
alias" check.
A test-case is added to ensure "--help" is passed through to the
underlying command of a shell alias.
Signed-off-by: Ian Wienand <iwienand@xxxxxxxxxx>
---
builtin/help.c | 7 +++----
git.c | 15 +++++++++++++++
t/t0014-alias.sh | 8 ++++++++
3 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/builtin/help.c b/builtin/help.c
index 222f994f86..5e9d5edbb2 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -547,11 +547,10 @@ static const char *check_git_cmd(const char* cmd)
* handle_builtin() in git.c rewrites "git cmd --help"
* to "git help --exclude-guides cmd", so we can use
* exclude_guides to distinguish "git cmd --help" from
- * "git help cmd". In the latter case, or if cmd is an
- * alias for a shell command, just print the alias
- * definition.
+ * "git help cmd". In the latter case, just print the
+ * alias definition.
*/
- if (!exclude_guides || alias[0] == '!') {
+ if (!exclude_guides) {
printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
free(alias);
exit(0);
diff --git a/git.c b/git.c
index 3d8e48cf55..4c93296550 100644
--- a/git.c
+++ b/git.c
@@ -691,12 +691,27 @@ static void strip_extension(const char **argv)
static void handle_builtin(int argc, const char **argv)
{
struct strvec args = STRVEC_INIT;
+ char *alias;
const char *cmd;
struct cmd_struct *builtin;
strip_extension(argv);
cmd = argv[0];
+ /*
+ * If this is a shell alias with --help, print it's alias
+ * mapping to be consistent with -h and pass it through
+ */
+ alias = alias_lookup(cmd);
+ if (alias && alias[0] == '!') {
+ if (argc > 1 && !strcmp(argv[1], "--help")) {
+ fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias);
+ free(alias);
+ return;
+ }
+ free(alias);
+ }
+
/* Turn "git cmd --help" into "git help --exclude-guides cmd" */
if (argc > 1 && !strcmp(argv[1], "--help")) {
int i;
diff --git a/t/t0014-alias.sh b/t/t0014-alias.sh
index 8d3d9144c0..7b1d559420 100755
--- a/t/t0014-alias.sh
+++ b/t/t0014-alias.sh
@@ -44,4 +44,12 @@ test_expect_success 'run-command formats empty args properly' '
test_cmp expect actual
'
+test_expect_success '--help is passed to execed alias' '
+ echo "echo \"\$@\"" > exec-alias.sh &&
+ chmod +x exec-alias.sh &&
+ git config alias.exec-alias "!\"$(pwd)/exec-alias.sh\"" &&
+ GIT_TRACE=1 git exec-alias --help &> output &&
+ test_i18ngrep -- "--help" output
+'
+
test_done
--
2.45.1
