Re: [PATCH 1/3] fast-export: allow dumping the refname mapping

[Jeff King <peff@peff.net>]

On Fri, Jun 19, 2020 at 11:51:06AM -0400, Eric Sunshine wrote:

> > +static void maybe_dump_anon(FILE *out, struct seen_set *seen,
> > +                           const char *orig, const char *anon)
> > +{
> > +       if (!out)
> > +               return;
> > +       if (!check_and_mark_seen(seen, orig))
> > +               fprintf(out, "%s %s\n", orig, anon);
> > +}
> 
> Nit: For a function which has only a single caller in this patch and
> one more caller added in 3/3, I wonder if the, um, convenience of this
> function short-circuiting as the very first thing it does outweighs
> the loss of clarity of having the callers make the check themselves.
> That is, have the caller do this instead:
> 
>     if (anonymized_refnames_handle)
>         dump_anon(anonymized_refnames_handle, ...);

<shrug> The names were long enough that I thought it was more clear not
to repeat myself. I actually wrote originally:

  if (anonymized_refnames_handle &&
      check_and_mark_seen(&seen, full_refname))
          fprintf(anonymized_refnames_handle, "%s %s\n",
	          full_refname, anon.buf));

but I wasn't sure if it was better not to duplicate the output format.
OTOH, we _could_ be using quote_path() for the path dumping, in which
case the formats would start to differ.

> > @@ -1213,6 +1249,9 @@ int cmd_fast_export(int argc, const char **argv, const char *prefix)
> > +       if (anonymized_refnames_file)
> > +               anonymized_refnames_handle = xfopen(anonymized_refnames_file, "w");
> 
> For completeness, do you want to close this file at some point?

My thought was to just let it auto-close at exit() time, since it's
effectively process-length.

> > diff --git a/t/t9351-fast-export-anonymize.sh b/t/t9351-fast-export-anonymize.sh
> > @@ -46,6 +46,18 @@ test_expect_success 'stream omits tag message' '
> > +test_expect_success 'refname mapping can be dumped' '
> > +       git fast-export --anonymize --all \
> > +               --dump-anonymized-refnames=refs.out >/dev/null &&
> > +       # we make no guarantees of the exact anonymized names,
> > +       # so just check that we have the right number and
> > +       # that a sample line looks sane.
> > +       # Note that master is not anonymized, and so not included
> > +       # in the mapping.
> > +       test_line_count = 6 refs.out &&
> 
> This hard-coded "6" seems rather fragile, causing the test to break if
> other refs are ever added or removed. Perhaps just count the refs
> dynamically?
> 
>     git show-ref >refs &&
>     nrefs=$(wc -l refs) &&
>     # Note that master is not anonymized, and so not included
>     # in the mapping.
>     nrefs=$((nrefs - 1))
>     test_line_count = $nrefs refs.out &&
> 
> and then drop the 'nrefs=$((nrefs - 1))' line and associated comment
> in patch 2/3 which removes the "master" special case.

That's exactly what I wrote originally, but it failed on macos due to
extra spaces in the "wc" output. There are other tests nearby that also
count the refs (e.g., exactly 2 branches), so I didn't think it was
worth trying to deal with the portability issue.

-Peff