From e6e76baaf4f0f5bfac5cf5708df536258c28f0f0 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 9 Oct 2018 13:59:07 +0200 Subject: [PATCH 1/3] help: redirect to aliased commands for "git cmd --help" As discussed in the thread for v1 of this patch [1] [2], this changes the rules for "git foo --help" when foo is an alias. (1) When invoked as "git help foo", we continue to print the "foo is aliased to bar" message and nothing else. (2) If foo is an alias for a shell command, print "foo is aliased to !bar" as usual. (3) Otherwise, print "foo is aliased to bar" to the standard error stream, and then break the alias string into words and pretend as if "git word[0] --help" were called. Getting the man page for git-cherry-pick directly with "git cp --help" is consistent with "--help" generally providing more comprehensive help than "-h". Printing the alias definition to stderr means that in certain cases (e.g. if help.format=web or if the pager uses an alternate screen and does not clear the terminal), one has 'cp' is aliased to 'cherry-pick -n' above the prompt when one returns to the terminal/quits the pager, which is a useful reminder that using 'cp' has some flag implicitly set. There are cases where this information vanishes or gets scrolled away, but being printed to stderr, it should never hurt. [1] https://public-inbox.org/git/20180926102636.30691-1-rv@rasmusvillemoes.dk/ [2] https://public-inbox.org/git/20180926184914.GC30680@sigill.intra.peff.net/ Signed-off-by: Rasmus Villemoes Signed-off-by: Junio C Hamano --- builtin/help.c | 34 +++++++++++++++++++++++++++++++--- 1 file changed, 31 insertions(+), 3 deletions(-) diff --git a/builtin/help.c b/builtin/help.c index 8d4f6dd301..e0e3fe62e9 100644 --- a/builtin/help.c +++ b/builtin/help.c @@ -415,9 +415,37 @@ static const char *check_git_cmd(const char* cmd) alias = alias_lookup(cmd); if (alias) { - printf_ln(_("'%s' is aliased to '%s'"), cmd, alias); - free(alias); - exit(0); + const char **argv; + int count; + + /* + * 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. + */ + if (!exclude_guides || alias[0] == '!') { + printf_ln(_("'%s' is aliased to '%s'"), cmd, alias); + free(alias); + exit(0); + } + /* + * Otherwise, we pretend that the command was "git + * word0 --help". We use split_cmdline() to get the + * first word of the alias, to ensure that we use the + * same rules as when the alias is actually + * used. split_cmdline() modifies alias in-place. + */ + fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias); + count = split_cmdline(alias, &argv); + if (count < 0) + die(_("bad alias.%s string: %s"), cmd, + split_cmdline_strerror(count)); + free(argv); + UNLEAK(alias); + return alias; } if (exclude_guides) From a9a60b94ccda5ff25faf51f39faeac11cac68346 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 9 Oct 2018 13:59:08 +0200 Subject: [PATCH 2/3] git.c: handle_alias: prepend alias info when first argument is -h Most git commands respond to -h anywhere in the command line, or at least as a first and lone argument, by printing the usage information. For aliases, we can provide a little more information that might be useful in interpreting/understanding the following output by prepending a line telling that the command is an alias, and for what. When one invokes a simple alias, such as "cp = cherry-pick" with -h, this results in $ git cp -h 'cp' is aliased to 'cherry-pick' usage: git cherry-pick [] ... ... When the alias consists of more than one word, this provides the additional benefit of informing the user which options are implicit in using the alias, e.g. with "cp = cherry-pick -n": $ git cp -h 'cp' is aliased to 'cherry-pick -n' usage: git cherry-pick [] ... ... For shell commands, we cannot know how it responds to -h, but printing this line to stderr should not hurt, and can help in figuring out what is happening in a case like $ git sc -h 'sc' is aliased to '!somecommand' somecommand: invalid option '-h' Suggested-by: Jeff King Signed-off-by: Rasmus Villemoes Signed-off-by: Junio C Hamano --- git.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/git.c b/git.c index a6f4b44af5..0211c2d4c0 100644 --- a/git.c +++ b/git.c @@ -318,6 +318,9 @@ static int handle_alias(int *argcp, const char ***argv) alias_command = (*argv)[0]; alias_string = alias_lookup(alias_command); if (alias_string) { + if (*argcp > 1 && !strcmp((*argv)[1], "-h")) + fprintf_ln(stderr, _("'%s' is aliased to '%s'"), + alias_command, alias_string); if (alias_string[0] == '!') { struct child_process child = CHILD_PROCESS_INIT; int nongit_ok; From 912104770d1b3b009a58e95ae57f6db65791b031 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 9 Oct 2018 13:59:09 +0200 Subject: [PATCH 3/3] git-help.txt: document "git help cmd" vs "git cmd --help" for aliases This documents the existing behaviour of "git help cmd" when cmd is an alias, as well as providing a hint to use the "git cmd --help" form to be taken directly to the man page for the aliased command. Signed-off-by: Rasmus Villemoes Signed-off-by: Junio C Hamano --- Documentation/git-help.txt | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Documentation/git-help.txt b/Documentation/git-help.txt index 83d25d825a..86a6b42345 100644 --- a/Documentation/git-help.txt +++ b/Documentation/git-help.txt @@ -29,6 +29,10 @@ guide is brought up. The 'man' program is used by default for this purpose, but this can be overridden by other options or configuration variables. +If an alias is given, git shows the definition of the alias on +standard output. To get the manual page for the aliased command, use +`git COMMAND --help`. + Note that `git --help ...` is identical to `git help ...` because the former is internally converted into the latter.