All of lore.kernel.org
 help / color / mirror / Atom feed
From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: Tim Schumacher <timschumi@gmx.de>,
	git@vger.kernel.org, pclouds@gmail.com
Subject: Re: [PATCH v3] Allow aliases that include other aliases
Date: Thu, 06 Sep 2018 11:40:14 -0700	[thread overview]
Message-ID: <xmqqy3cezcz5.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20180906145942.GB1209@sigill.intra.peff.net> (Jeff King's message of "Thu, 6 Sep 2018 10:59:42 -0400")

Jeff King <peff@peff.net> writes:

> On Thu, Sep 06, 2018 at 12:16:58PM +0200, Tim Schumacher wrote:
>
>> @@ -691,17 +692,23 @@ static int run_argv(int *argcp, const char ***argv)
>>  		/* .. then try the external ones */
>>  		execv_dashed_external(*argv);
>>  
>> -		/* It could be an alias -- this works around the insanity
>> +		if (string_list_has_string(&cmd_list, *argv[0]))
>> +			die(_("loop alias: %s is called twice"), *argv[0]);
>
> I pointed this out in my response to Ævar, but I want to make sure it
> gets seen. This call assumes the list is sorted, but...
>
>> +		string_list_append(&cmd_list, *argv[0]);
>
> This will create an unsorted list. You'd have to use
> string_list_insert() here for a sorted list, or
> unsorted_string_list_has_string() in the earlier call.

Correct.

Also, normal users who have never seen this loop that implements
alias expansion would not have a clue when they see "called twice".

I actually think the caller should also pass cmd to run_argv() and
then we should use it (and not argv[]) in this die() message.  When
the original command was foo that is aliased to bar, which in turn
is aliased to baz, which in turn is aliased to bar, especially that
"git foo" invocation was in a random script written six weeks ago by
the user, it would be a lot more helpful to see 

    "alias loop detected: expansion of 'git foo' does not terminate"

than

    "loop alias: bar is called twice".

given that 'bar' is not something the user called, or written in the
script she wrote six weeks ago.

> It's unfortunate that string_list makes this so easy to get wrong.
>
>> +
>> +		/*
>> +		 * It could be an alias -- this works around the insanity
>>  		 * of overriding "git log" with "git show" by having
>>  		 * alias.log = show
>>  		 */
>> -		if (done_alias)
>> -			break;
>>  		if (!handle_alias(argcp, argv))
>>  			break;
>> -		done_alias = 1;
>> +		done_alias++;
>
> I don't think anybody cares about done_alias being an accurate count.
> Should we just leave this as-is?

Good point.  The only caller treats it as a bool (i.e. "should the
failure be reported as failure to expand an alias cmd which resulted
in (updated) argv[0] that is not a git command?").

  reply	other threads:[~2018-09-06 18:40 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-05  8:54 [RFC PATCH v2] Allow aliases that include other aliases Tim Schumacher
2018-09-05 15:48 ` Duy Nguyen
2018-09-05 19:02   ` Tim Schumacher
2018-09-05 17:12 ` Junio C Hamano
2018-09-05 19:12   ` Tim Schumacher
2018-09-05 17:34 ` Jeff King
2018-09-05 20:02   ` Tim Schumacher
2018-09-06 13:38     ` Ævar Arnfjörð Bjarmason
2018-09-06 14:17     ` Ævar Arnfjörð Bjarmason
2018-10-18 22:57       ` [PATCH] alias: detect loops in mixed execution mode Ævar Arnfjörð Bjarmason
2018-10-19  8:28         ` Ævar Arnfjörð Bjarmason
2018-10-19 22:09           ` Jeff King
2018-10-20 10:52             ` Ævar Arnfjörð Bjarmason
2018-10-19 22:07         ` Jeff King
2018-10-20 11:14           ` Ævar Arnfjörð Bjarmason
2018-10-20 18:58             ` Jeff King
2018-10-20 19:18               ` Ævar Arnfjörð Bjarmason
2018-10-22 21:15                 ` Jeff King
2018-10-22 21:28                   ` Ævar Arnfjörð Bjarmason
2018-10-22  1:23               ` Junio C Hamano
2018-10-26  8:39               ` Jeff King
2018-10-26 12:44                 ` Ævar Arnfjörð Bjarmason
2018-10-29  3:44                 ` Junio C Hamano
2018-10-29 14:17                   ` Jeff King
2018-09-05 21:51   ` [RFC PATCH v2] Allow aliases that include other aliases Junio C Hamano
2018-09-06 10:16 ` [PATCH v3] " Tim Schumacher
2018-09-06 14:01   ` Ævar Arnfjörð Bjarmason
2018-09-06 14:57     ` Jeff King
2018-09-06 15:10       ` Ævar Arnfjörð Bjarmason
2018-09-06 16:18         ` Jeff King
2018-09-06 19:05       ` Tim Schumacher
2018-09-06 19:17         ` Jeff King
2018-09-06 14:59   ` Jeff King
2018-09-06 18:40     ` Junio C Hamano [this message]
2018-09-06 19:05       ` Jeff King
2018-09-06 19:31       ` Tim Schumacher
2018-09-07 22:44 ` [RFC PATCH v4 1/3] Add support for nested aliases Tim Schumacher
2018-09-07 22:44   ` [RFC PATCH v4 2/3] Show the call history when an alias is looping Tim Schumacher
2018-09-08 13:34     ` Duy Nguyen
2018-09-08 16:29       ` Jeff King
2018-09-07 22:44   ` [RFC PATCH v4 3/3] t0014: Introduce alias testing suite Tim Schumacher
2018-09-07 23:38     ` Eric Sunshine
2018-09-14 23:12       ` Tim Schumacher
2018-09-16  7:21         ` Eric Sunshine
2018-09-08 13:28   ` [RFC PATCH v4 1/3] Add support for nested aliases Duy Nguyen
2018-09-16  7:46     ` Tim Schumacher
2018-09-17 15:37       ` Junio C Hamano
2018-09-21 12:45         ` Tim Schumacher
2018-09-21 15:59           ` Junio C Hamano
2018-09-16  7:50   ` [PATCH v5 " Tim Schumacher
2018-09-16  7:50     ` [PATCH v5 2/3] Show the call history when an alias is looping Tim Schumacher
2018-09-16  7:50     ` [PATCH v5 3/3] t0014: Introduce an alias testing suite Tim Schumacher

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=xmqqy3cezcz5.fsf@gitster-ct.c.googlers.com \
    --to=gitster@pobox.com \
    --cc=git@vger.kernel.org \
    --cc=pclouds@gmail.com \
    --cc=peff@peff.net \
    --cc=timschumi@gmx.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.