[PATCH 0/12] fixing the remainder of the C23 strchr warnings

[Jeff King <peff@peff.net>]

This series fixes the rest of the warnings you might see on recent glibc
or other C23 libc where:

  const char *in = ...;
  char *out = strchr(in, ...);

now complains instead of quietly assigning the const pointer to a
non-const one. It's all textually independent of the other fixes, but
if you want a clean build you'll need the others. I think Collin's fixes
have hit master already, but my jk/c23-const-preserving-fixes are still
slated for 'next'.

Some of my fixes are similar to what Michael posted in:

  https://lore.kernel.org/git/cover.1774537954.git.git@grubix.eu/

but for most of them I took a somewhat different approach. So this would
be applied instead of those patches.

The patches are:

  [01/12]: convert: add const to fix strchr() warnings
  [02/12]: http: add const to fix strchr() warnings
  [03/12]: transport-helper: drop const to fix strchr() warnings

    These ones are obvious fixes that just match the type declarations
    to their uses.

  [04/12]: pager: explicitly cast away strchr() constness
  [05/12]: run-command: explicitly cast away constness when assigning to void

    These are ones where I think an explicit cast is the least-bad
    option.

  [06/12]: find_last_dir_sep(): convert inline function to macro

    This is the one that gets repeated a zillion times when you build
    because it's in a header file. ;) It takes a slightly different
    approach than Collin's in:

      https://lore.kernel.org/git/e6f7e2eddbc9aef1c21f661420a4b8cb9cd8e2c1.1770095829.git.collin.funk1@gmail.com/

    which I think reduces the fallout through the rest of the codebase.

  [07/12]: pseudo-merge: fix disk reads from find_pseudo_merge()

    This one is...spicy. I think there are probably actual bugs here,
    but my hope is that this takes us in the right direction (and shuts
    up the warning).

  [08/12]: skip_prefix(): check const match between in and out params

    And here is where we might get controversial. It introduces some
    macro hackery that makes it safe and easy to use skip_prefix() with
    const or non-const strings. I _think_ it should just work
    everywhere, but I won't be surprised if some compiler somewhere
    complains about the construct. Coverity does, but it is so full of
    false positives that adding more is not a big deal.

  [09/12]: pkt-line: make packet_reader.line non-const
  [10/12]: range-diff: drop const to fix strstr() warnings
  [11/12]: http: drop const to fix strstr() warning
  [12/12]: refs/files-backend: drop const to fix strchr() warning

     And then these are all obvious fixes that are only made possible by
     the skip_prefix() magic above. Well, possible without extra ugly
     casts everywhere.

 builtin/config.c    |  7 ++++---
 builtin/rev-parse.c | 40 ++++++++++++++++++++--------------------
 convert.c           |  3 ++-
 git-compat-util.h   | 23 ++++++++++++++++++-----
 http-push.c         |  2 +-
 pager.c             |  3 ++-
 pseudo-merge.c      | 32 +++++++++++++++++++-------------
 revision.c          | 25 +++++++++++++++----------
 run-command.c       |  4 ++--
 transport-helper.c  |  3 ++-
 10 files changed, 85 insertions(+), 57 deletions(-)

-Peff