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Re: [PATCH 5/6] help: correct logic error in combining --all and --config

From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date
Sep 8, 2021, 19:37 UTC
Message-ID
<87bl52hn40.fsf@evledraar.gmail.com>
In-Reply-To
<CAPig+cSK+wLPUDuGf1d41J_F5jQS+J=a=7kHQLV07-ZKZW9GsA@mail.gmail.com>
On Wed, Sep 08 2021, Eric Sunshine wrote:
Show 42 quoted lines
> On Wed, Sep 8, 2021 at 11:24 AM Ævar Arnfjörð Bjarmason
> <avarab@gmail.com> wrote:
>> Fix a bug in the --config option that's been there ever since its
>> introduction in 3ac68a93fd2 (help: add --config to list all available
>> config, 2018-05-26). Die when --all and --config are combined,
>> combining them doesn't make sense.
>>
>> The code for the --config option when combined with an earlier
>> refactoring done to support the --guide option in
>> 65f98358c0c (builtin/help.c: add --guide option, 2013-04-02) would
>> cause us to take the "--all" branch early and ignore the --config
>> option.
>>
>> Let's instead list these as incompatible, both in the synopsis and
>> help output, and enforce it in the code itself.
>>
>> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
>> ---
>> diff --git a/builtin/help.c b/builtin/help.c
>> @@ -549,18 +550,26 @@ int cmd_help(int argc, const char **argv, const char *prefix)
>> +       /* Incompatible options */
>> +       if (show_all + !!show_config + show_guides > 1)
>> +               usage_with_options(builtin_help_usage, builtin_help_options);
>
> I personally find it highly frustrating when a program merely dumps
> the usage statement without any explanation of what exactly it doesn't
> like about the command-line. Printing out a simple:
>
>     --all, --guides, --config are mutually exclusive
>
> message would go a long way toward reducing the frustration level.
>
> (Aside: I also find it more hostile than helpful when programs dump
> the usage statement for a command-line invocation error -- even if
> preceded by an explanation of the error -- since the explanation
> usually gets drowned-out by the often multi-page usage text, and the
> user has to go spelunking around the wall of output to try to figure
> out what actually went wrong. It's much more helpful and easy to
> figure out what went wrong with the invocation when only a simple
> error message is printed -- without usage statement. However, that's a
> separate battle, as Git already has plenty of places which dump the
> usage statement in response to an invocation error.)
I'll make it emit something more helpful.

More generally I've got quite a bit of parse_options() improvements queued up locally that I've been trying to trickle in at the rate I can get them through the list, review over at [1] would be much appreciated.

I wonder if we can do this automatically, we already have the builtin_help_usage, we could parse that in the general case and find that certain options are mutually exclusive per the examples there.

We'd then discover what option we parsed when usage_with_options() was called, and automatically emit a useful message in these sorts of cases.

Of course the usage strings might be incomplete or wrong, but part of the point would be to find those cases & a test mode to die() if a command was called with some option combinations not suggested as working according to its documented usage...

https://lore.kernel.org/git/cover-0.2-00000000000-20210901T110917Z-avarab@gmail.com/
Previous: Eric SunshineNext: Eric Sunshine
Message 11 of 45 in “help: fix usage nits & bugs, completion shellscript->C”
  1. 0/6 help: fix usage nits & bugs, completion shellscript->CÆvar Arnfjörð Bjarmason, Sep 8, 2021
  2. 1/6 help: correct the usage string in -h and documentationÆvar Arnfjörð Bjarmason, Sep 8, 2021
  3. 2/6 help: correct usage string for "git help --guides"Ævar Arnfjörð Bjarmason, Sep 8, 2021
  4. 3/6 help tests: add test for --config outputÆvar Arnfjörð Bjarmason, Sep 8, 2021
  5. 4/6 help: refactor "for_human" control flow in cmd_help()Ævar Arnfjörð Bjarmason, Sep 8, 2021
  6. Eric SunshineSep 8, 2021
  7. Junio C HamanoSep 8, 2021
  8. Ævar Arnfjörð BjarmasonSep 8, 2021
  9. 5/6 help: correct logic error in combining --all and --configÆvar Arnfjörð Bjarmason, Sep 8, 2021
  10. Eric SunshineSep 8, 2021
  11. Ævar Arnfjörð BjarmasonSep 8, 2021
  12. Eric SunshineSep 10, 2021
  13. Ævar Arnfjörð BjarmasonSep 10, 2021
  14. 6/6 help / completion: make "git help" do the hard workÆvar Arnfjörð Bjarmason, Sep 8, 2021
  15. 0/5 help: fix usage nits & bugs, completion shellscript->CÆvar Arnfjörð Bjarmason, Sep 10, 2021
  16. 1/5 help: correct the usage string in -h and documentationÆvar Arnfjörð Bjarmason, Sep 10, 2021
  17. Junio C HamanoSep 11, 2021
  18. Ævar Arnfjörð BjarmasonSep 11, 2021
  19. 2/5 help: correct usage & behavior of "git help --guides"Ævar Arnfjörð Bjarmason, Sep 10, 2021
  20. Philip OakleySep 10, 2021
  21. Philip OakleySep 10, 2021
  22. Ævar Arnfjörð BjarmasonSep 21, 2021
  23. Philip OakleySep 21, 2021
  24. Junio C HamanoSep 11, 2021
  25. 3/5 help tests: add test for --config outputÆvar Arnfjörð Bjarmason, Sep 10, 2021
  26. Junio C HamanoSep 11, 2021
  27. Ævar Arnfjörð BjarmasonSep 11, 2021
  28. Philip OakleySep 13, 2021
  29. 4/5 help: correct logic error in combining --all and --configÆvar Arnfjörð Bjarmason, Sep 10, 2021
  30. Junio C HamanoSep 10, 2021
  31. 5/5 help / completion: make "git help" do the hard workÆvar Arnfjörð Bjarmason, Sep 10, 2021
  32. Junio C HamanoSep 11, 2021
  33. 0/9 help: fix usage nits & bugs, completion shellscript->CÆvar Arnfjörð Bjarmason, Sep 21, 2021
  34. 1/9 help: correct the usage string in -h and documentationÆvar Arnfjörð Bjarmason, Sep 21, 2021
  35. 2/9 help: correct usage & behavior of "git help --guides"Ævar Arnfjörð Bjarmason, Sep 21, 2021
  36. Junio C HamanoSep 23, 2021
  37. 3/9 help tests: add test for --config outputÆvar Arnfjörð Bjarmason, Sep 21, 2021
  38. 4/9 help: correct logic error in combining --all and --configÆvar Arnfjörð Bjarmason, Sep 21, 2021
  39. 5/9 help: correct logic error in combining --all and --guidesÆvar Arnfjörð Bjarmason, Sep 21, 2021
  40. 6/9 help: simplify by moving to OPT_CMDMODE()Ævar Arnfjörð Bjarmason, Sep 21, 2021
  41. Junio C HamanoSep 23, 2021
  42. Junio C HamanoSep 23, 2021
  43. 7/9 help tests: test --config-for-completion option & outputÆvar Arnfjörð Bjarmason, Sep 21, 2021
  44. 9/9 help: move column config discovery to help.c libraryÆvar Arnfjörð Bjarmason, Sep 21, 2021
  45. 8/9 help / completion: make "git help" do the hard workÆvar Arnfjörð Bjarmason, Sep 21, 2021

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