Re: [PATCH 2/7] git.c: let builtins opt for handling `pager.foo` themselves

On 11 July 2017 at 12:24, Jeff King [off-list ref] wrote:

On Mon, Jul 10, 2017 at 11:55:15PM +0200, Martin Ågren wrote:

quoted

To allow individual builtins to make more informed decisions about when
to respect `pager.foo`, introduce a flag IGNORE_PAGER_CONFIG. If the flag
is set, do not check `pager.foo`. This applies to two code-paths -- one
in run_builtin() and one in execv_dashed_external().

Can this ever trigger in execv_dashed_external()? We should only get
there if get_builtin() returned NULL in the first place. Otherwise, we'd
run and exited via handle_builtin().

I can trigger it with this:

$ git -c pager.tag="echo paging" -c pager.tag.list=no -c alias.t=tag t -l

where the alias is what triggers it and the two pager-configurations
demonstrate the effect.

So I think this hunk:

quoted

@@ -543,11 +550,14 @@ static void execv_dashed_external(const char **argv)
 {
      struct child_process cmd = CHILD_PROCESS_INIT;
      int status;
+     struct cmd_struct *builtin;

      if (get_super_prefix())
              die("%s doesn't support --super-prefix", argv[0]);

-     if (use_pager == -1)
+     builtin = get_builtin(argv[0]);
+     if (use_pager == -1 &&
+         !(builtin && builtin->option & IGNORE_PAGER_CONFIG))
              use_pager = check_pager_config(argv[0]);
      commit_pager_choice();

...can just go away.

If I remove this, the call I gave above will page although it
shouldn't, and it doesn't if I keep this hunk. There's this in
run_argv: "If we tried alias and futzed with our environment, it no
longer is safe to invoke builtins directly in general.  We have to
spawn them as dashed externals." There's also a NEEDSWORK.

Although, thinking about it, I'm not sure why when I remove this hunk,
the child process doesn't set up the paging correctly. Maybe something
related to my using "-c", or something about the launching of child
processes. Those are both areas where I lack knowledge. Will look into
it.

Martin