[PATCH] t5702: be more resilient to env quoting

[Jeff King <peff@peff.net>]

A few tests in t5702 check whether we specify the v2 protocol via the
GIT_PROTOCOL environment variable. They do this by redirecting the
output of "env" into a file and grepping it. But our exact pattern
depends on how env quotes its output. GNU coreutils 9.10 will output
this:

  GIT_PROTOCOL=version=2

but version 9.12 will output this:

  GIT_PROTOCOL='version=2'

It doesn't quote every variable, but the presence of "=" now triggers
it. We could loosen our regex to accommodate both versions, but there's
a simpler fix. We only care about the value of one variable, so we can
just print it using the shell invoked for the server-side command.

Note that this new formula is slightly less strict: it allows
GIT_PROTOCOL as an empty string in addition to it being missing. But
that's OK; they both mean the same thing to the child Git process.

Likewise, it's actually more strict when we do expect the v2 protocol:
it checks the contents of the whole GIT_PROTOCOL rather than a partial
grep. In practice it's the same for now (we only ever set protocol=2),
but I think in the long run being strict is better (if we do add
something else, the test will break and we can consider how to handle it
then).

Signed-off-by: Jeff King <peff@peff.net>
---
The new coreutils hit Debian unstable, so I ran into this doing my usual
daily "make test". I wondered what idiot did the overly-complicated
"env" invocation in the first place, but naturally it turns out it was
me.

 t/t5702-protocol-v2.sh | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
index 7e69ba7f84..a66adfbc3b 100755
--- a/t/t5702-protocol-v2.sh
+++ b/t/t5702-protocol-v2.sh
@@ -929,28 +929,35 @@ test_expect_success 'file:// --negotiate-only with protocol v0' '
 test_expect_success 'push with custom path does not request v2' '
 	rm -f env.trace &&
 	git -C client push \
-		--receive-pack="env >../env.trace; git-receive-pack" \
+		--receive-pack="
+			echo GIT_PROTOCOL=\$GIT_PROTOCOL >../env.trace
+			git-receive-pack" \
 		origin HEAD:refs/heads/custom-push-test &&
-	test_path_is_file env.trace &&
-	test_grep ! ^GIT_PROTOCOL env.trace
+	echo GIT_PROTOCOL= >expect &&
+	test_cmp expect env.trace
 '
 
 test_expect_success 'fetch with custom path does request v2' '
 	rm -f env.trace &&
 	git -C client fetch \
-		--upload-pack="env >../env.trace; git-upload-pack" \
+		--upload-pack="
+			echo GIT_PROTOCOL=\$GIT_PROTOCOL >../env.trace
+			git-upload-pack" \
 		origin HEAD &&
-	test_grep ^GIT_PROTOCOL=version=2 env.trace
+	echo GIT_PROTOCOL=version=2 >expect &&
+	test_cmp expect env.trace
 '
 
 test_expect_success 'archive with custom path does not request v2' '
 	rm -f env.trace &&
 	git -C client archive \
-		--exec="env >../env.trace; git-upload-archive" \
+		--exec="
+			echo GIT_PROTOCOL=\$GIT_PROTOCOL >../env.trace
+			git-upload-archive" \
 		--remote=origin \
 		HEAD >/dev/null &&
-	test_path_is_file env.trace &&
-	test_grep ! ^GIT_PROTOCOL env.trace
+	echo "GIT_PROTOCOL=" >expect &&
+	test_cmp expect env.trace
 '
 
 test_expect_success 'reject client packfile-uris if not advertised' '
-- 
2.56.0.613.g16c2199927