Re: [PATCH] t: use portable wrapper for readlink(1)

On 2021-06-18 at 16:32:22, Jeff King wrote:

Not all systems have a readlink program available for use by the shell.
This causes t3210 to fail on at least AIX. Let's provide a perl
one-liner to do the same thing, and use it there.

I also updated calls in t9802. Nobody reported failure there, but it's
the same issue. Presumably nobody actually tests with p4 on AIX in the
first place (if it is even available there).

I left the use of readlink in the "--valgrind" setup in test-lib.sh, as
valgrind isn't available on exotic platforms anyway (and I didn't want
to increase dependencies between test-lib.sh and test-lib-functions.sh).

There's one other curious case. Commit d2addc3b96 (t7800: readlink may
not be available, 2016-05-31) fixed a similar case. We can't use our
wrapper function there, though, as it's inside a sub-script triggered by
Git. It uses a slightly different technique ("ls" piped to "sed"). I
chose not to use that here as it gives confusing "ls -l" output if the
file is unexpectedly not a symlink (which is OK for its limited use, but
potentially confusing for general use within the test suite). The perl
version emits the empty string.

Reported-by: Ævar Arnfjörð Bjarmason <redacted>
Signed-off-by: Jeff King <redacted>
---
This is a re-post that doesn't seem to have made it into "seen"; the
original[1] was buried in a thread, but Ævar reported there that it
fixes t3210 on his AIX build.

[1] https://lore.kernel.org/git/YLk0Zm2J6VOA%2Flks@coredump.intra.peff.net/ (local)

In case I didn't say it up in the previous post, this looks fine to me.
Using Perl here seems like a fine solution.  If we needed to in the
future, we could add this to test-tool and use the real readlink(2), but
we can hold off until we decide we need to.
-- 
brian m. carlson (he/him or they/them)
Toronto, Ontario, CA