Subject: Re: [PATCH v2 2/2] test-lib-functions: fix test_subcommand_inexact

From: Junio C Hamano <[email-masked]>
Date: Thu, 24 Mar 2022 13:48:15 -0700

"Derrick Stolee via GitGitGadget" <[email-masked]> writes:

> From: Derrick Stolee <[email-masked]>
>
> The implementation of test_subcommand_inexact() was originally
> introduced in e4d0c11c0 (repack: respect kept objects with '--write-midx
> -b', 2021-12-20) with the intention to allow finding a subcommand based
> on an initial set of arguments. The inexactness was intended as a way to
> allow flexible options beyond that initial set, as opposed to
> test_subcommand() which requires that the full list of options is
> provided in its entirety.
>
> The implementation began by copying test_subcommand() and replaced the
> repeated argument 'printf' statement to append ".*" instead of "," to
> each argument. This has a few drawbacks:
>
> 1. Most importantly, this repeats the use of ".*" within 'expr', so the
>    inexact match is even more flexible than expected. It allows the list
>    of arguments to exist as a subsequence (with any other items included
>    between those arguments).
>
> 2. The line 'expr="$(expr%,}"' that previously removed a trailing comma
>    now no longer does anything, since the string ends with ".*".
>
> Both of these issues are fixed by keeping the addition of the comma in
> the printf statement, then adding ".*" after stripping out the trailing
> comma.
>
> All existing tests continue to pass with this change. There was one
> instance from t7700-repack.sh that was taking advantage of this
> flexibility, but it was removed in the previous change.

Of course all existing tests continue to pass, as we no longer have
any user of test_subcommand_inexact after the previous step ;-).

Among

 (1) doing nothing,
 (2) removing, and
 (3) clarifying the implementation,

my preference would be 2 > 1 > 3.  If we add

 (4) clarify the implementation and document what kind of inexactness we
     tolerate with an updated comment"

to the mix, that would come before all 3 others, though.

Perhaps squash something like this in?

 t/test-lib-functions.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git i/t/test-lib-functions.sh w/t/test-lib-functions.sh
index 0f439c99d6..6f6afae847 100644
--- i/t/test-lib-functions.sh
+++ w/t/test-lib-functions.sh
@@ -1789,8 +1789,8 @@ test_subcommand () {
 }
 
 # Check that the given command was invoked as part of the
-# trace2-format trace on stdin, but without an exact set of
-# arguments.
+# trace2-format trace on stdin, but only require that the
+# initial arguments are given as specified.
 #
 #	test_subcommand [!] <command> <args>... < <trace>
 #