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Re: [PATCH 3/3] odb: drop gaps in object info flag values

From
Junio C Hamano <gitster@pobox.com>
Date
Jan 26, 2026, 18:13 UTC
Message-ID
<xmqqpl6wi6n4.fsf@gitster.g>
In-Reply-To
<add7c86f-9d5e-4136-8c3d-a04df523487b@web.de>
René Scharfe <l.s.r@web.de> writes:
Show 14 quoted lines
>> I wonder if this series can be restructured a bit to demonstrate the
>> benefit of moving to enum a bit more prominently.  For example, even
>> at the end of the three patches, odb_read_object_info_extended()
>> still takes an "unsigned flags" parameter, but it is meant to take
>> this new enum, isn't it?  If we do the "#define to enum" conversion
>> (without renumbering) first, then "unsigned to enum", would it, with
>> appropriate compiler warning flags, already reveal the existing bugs
>> that happened to be working OK as potential problems?  And with that,
>> fixes in 1/3 and 2/3 would demonstrate why #define to enum" is worth
>> doing very well.  And after all that, we can renumber the enums in a
>> separate and final step.
> With -Wenum-conversion you can get GCC to report implicit conversions
> between different enum types (like in the backfill case), but I don't
> see a way to warn about conversions from int (the fsck case).

Yes, that is why I suggested "unsigned to enum" change after doing "#define to enum" conversion. If a caller passes an enum with HAS_OBJECT_* to odb_read_object_info_extended() that expects "unsigned flags", it would not be warned, but if the callee expects "enum object_info_flags", passing HAS_OBJECT_* enum to it would be flagged, right? We may need to give the currently-unnamed enum with HAS_OBJECT_* a name first.

Show 10 quoted lines
> https://stackoverflow.com/questions/4669454/how-to-make-gcc-warn-about-passing-wrong-enum-to-a-function
> suggests using -Wenum-compare and macros to sneak in a comparison, but
> that doesn't seem to catch more than -Wenum-conversion, which doesn't
> need any macros.
>
> https://godbolt.org/z/Whvc7Mf1n
>
> Perhaps sparse can do that?
>
> René
Previous: René ScharfeNext: Patrick Steinhardt
Message 13 of 23 in “Small fixups for `OBJECT_INFO` flags”
  1. 0/3 Small fixups for `OBJECT_INFO` flagsPatrick Steinhardt, Jan 26, 2026
  2. 1/3 builtin/backfill: fix flags passed to `odb_has_object()`Patrick Steinhardt, Jan 26, 2026
  3. Derrick StoleeJan 26, 2026
  4. Junio C HamanoJan 26, 2026
  5. Justin ToblerFeb 9, 2026
  6. Karthik NayakFeb 10, 2026
  7. Karthik NayakFeb 10, 2026
  8. 2/3 builtin/fsck: fix flags passed to `odb_has_object()`Patrick Steinhardt, Jan 26, 2026
  9. Justin ToblerFeb 9, 2026
  10. 3/3 odb: drop gaps in object info flag valuesPatrick Steinhardt, Jan 26, 2026
  11. Junio C HamanoJan 26, 2026
  12. René ScharfeJan 26, 2026
  13. Junio C HamanoJan 26, 2026
  14. Patrick SteinhardtJan 27, 2026
  15. Justin ToblerFeb 9, 2026
  16. Justin ToblerFeb 9, 2026
  17. Junio C HamanoJan 26, 2026
  18. 0/5 Small fixups for `OBJECT_INFO` flagsPatrick Steinhardt, Feb 12, 2026
  19. 1/5 builtin/backfill: fix flags passed to `odb_has_object()`Patrick Steinhardt, Feb 12, 2026
  20. 2/5 builtin/fsck: fix flags passed to `odb_has_object()`Patrick Steinhardt, Feb 12, 2026
  21. 3/5 odb: drop gaps in object info flag valuesPatrick Steinhardt, Feb 12, 2026
  22. 4/5 odb: convert object info flags into an enumPatrick Steinhardt, Feb 12, 2026
  23. 5/5 odb: convert `odb_has_object()` flags into an enumPatrick Steinhardt, Feb 12, 2026

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