Re: should git maintenance prefetch be taught to honor remote.fetch refspec?

[Tom Saeger <tom.saeger@oracle.com>]

On Fri, Apr 02, 2021 at 06:32:56PM -0400, Eric Sunshine wrote:
> On Fri, Apr 2, 2021 at 4:43 PM Derrick Stolee <stolee@gmail.com> wrote:
> > I have a branch available [1], but I'm seeing some failures only
> > on FreeBSD [2] and I can't understand why that platform is failing
> > this test. The current version (as of this writing) does not do
> > the substring replacement technique, and hence it just gives up
> > on exact matches. I will try the substring approach as an
> > alternative and see where that gets me.
> >
> > [1] https://github.com/gitgitgadget/git/pull/924
> > [2] https://github.com/gitgitgadget/git/pull/924/checks?check_run_id=2256079534
> 
> The "+" in patterns such as `+refs/heads/\\*:refs/prefetch...` is what
> is throwing it off. FreeBSD `grep` doesn't seem to like it, though
> it's not clear why. Escaping it the same way as you escaped "*"
> doesn't make it work. Replacing "+" with catchall "." does work, so
> that's one way to fix it.
> 
> However, all the escaping you need to do in these refspec patterns to
> pass them to `grep` is ugly. A much better solution may be to change
> the `grep` in test-lib-functions.sh:test_subcommand() to `grep -F` to
> force it to match literally. That way, you can drop all the backslash
> escaping, including those in front of "[" and "]". A cursory audit of
> callers test_subcommand() seems to indicate that none of them pass
> regex patterns, so using `-F` is probably safe and a good idea.
> 
> By the way, the `coccinelle` check is also "failing", correctly
> suggesting that you change:
> 
>     strbuf_addf(&replace, ":refs/prefetch/");
> 
> to:
> 
>     strbuf_addstr(&replace, ":refs/prefetch/");
> 
> in `builtin/gc.c`.

Was curious - so rolled all Eric's feedback into a patch.

This passes 'make test' and 'make coccicheck' locally, not sure about FreeBSD.

Stolee - can you squash this onto your PR and try it if you agree?

--Tom


diff --git a/builtin/gc.c b/builtin/gc.c
index 98229bda25fd..eb4a03a2b47b 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -894,7 +894,7 @@ static int fetch_remote(struct remote *remote, void *cbdata)
 		if (index_of_refs) {
 			struct strbuf replace = STRBUF_INIT;
 			strbuf_add(&replace, raw, index_of_refs - raw);
-			strbuf_addf(&replace, ":refs/prefetch/");
+			strbuf_addstr(&replace, ":refs/prefetch/");
 			strbuf_addstr(&replace, index_of_refs + 6);
 
 			strvec_push(&child.args, replace.buf);
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index 93ae93b73611..3366ea188782 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -142,8 +142,8 @@ test_expect_success 'prefetch multiple remotes' '
 	test_commit -C clone2 two &&
 	GIT_TRACE2_EVENT="$(pwd)/run-prefetch.txt" git maintenance run --task=prefetch 2>/dev/null &&
 	fetchargs="--prune --no-tags --no-write-fetch-head --recurse-submodules=no --refmap= --quiet" &&
-	test_subcommand git fetch remote1 $fetchargs +refs/heads/\\*:refs/prefetch/remotes/remote1/\\* <run-prefetch.txt &&
-	test_subcommand git fetch remote2 $fetchargs +refs/heads/\\*:refs/prefetch/remotes/remote2/\\* <run-prefetch.txt &&
+	test_subcommand git fetch remote1 $fetchargs +refs/heads/*:refs/prefetch/remotes/remote1/* <run-prefetch.txt &&
+	test_subcommand git fetch remote2 $fetchargs +refs/heads/*:refs/prefetch/remotes/remote2/* <run-prefetch.txt &&
 	test_path_is_missing .git/refs/remotes &&
 	git log prefetch/remotes/remote1/one &&
 	git log prefetch/remotes/remote2/two &&
@@ -169,12 +169,12 @@ test_expect_success 'prefetch custom refspecs' '
 	fetchargs="--prune --no-tags --no-write-fetch-head --recurse-submodules=no --refmap= --quiet" &&
 
 	# skips second refspec because it is not a pattern type
-	rs1="+refs/heads/\\*:refs/prefetch/remotes/remote1/\\*" &&
+	rs1="+refs/heads/*:refs/prefetch/remotes/remote1/*" &&
 	rs2="+refs/heads/special/fetched:refs/prefetch/heads/fetched" &&
 	rs3="^refs/heads/special/secret/not-fetched" &&
 
 	test_subcommand git fetch remote1 $fetchargs $rs1 $rs2 $rs3 <prefetch-refspec.txt &&
-	test_subcommand git fetch remote2 $fetchargs +refs/heads/\\*:refs/prefetch/remotes/remote2/\\* <prefetch-refspec.txt &&
+	test_subcommand git fetch remote2 $fetchargs +refs/heads/*:refs/prefetch/remotes/remote2/* <prefetch-refspec.txt &&
 
 	# first refspec is overridden by second
 	test_must_fail git rev-parse refs/prefetch/special/fetched &&
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 6348e8d7339c..e9a1cf3e227a 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -1652,9 +1652,9 @@ test_subcommand () {
 
 	if test -n "$negate"
 	then
-		! grep "\[$expr\]"
+		! grep -F "$expr"
 	else
-		grep "\[$expr\]"
+		grep -F "$expr"
 	fi
 }