[PATCH 10/18] chainlint.pl: don't flag broken &&-chain if `$?` handled explicitly

["Eric Sunshine via GitGitGadget" <gitgitgadget@gmail.com>]

From: Eric Sunshine <sunshine@sunshineco.com>

There are cases in which tests capture and check a command's exit code
explicitly without employing test_expect_code(). They do so by
intentionally breaking the &&-chain since it would be impossible to
capture "$?" in the failing case if the `status=$?` assignment was part
of the &&-chain. Since such constructs are manually checking the exit
code, their &&-chain breakage is legitimate and safe, thus should not be
flagged. Therefore, stop flagging &&-chain breakage in such cases.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
---
 t/chainlint.pl                        |  6 ++++++
 t/chainlint/chain-break-status.expect |  9 +++++++++
 t/chainlint/chain-break-status.test   | 11 +++++++++++
 3 files changed, 26 insertions(+)
 create mode 100644 t/chainlint/chain-break-status.expect
 create mode 100644 t/chainlint/chain-break-status.test

diff --git a/t/chainlint.pl b/t/chainlint.pl
index ba3fcb0c8e6..14e1db3519a 100755
--- a/t/chainlint.pl
+++ b/t/chainlint.pl
@@ -497,6 +497,12 @@ sub accumulate {
 	# did previous command end with "&&", "|", "|| return" or similar?
 	goto DONE if match_ending($tokens, \@safe_endings);
 
+	# if this command handles "$?" specially, then okay for previous
+	# command to be missing "&&"
+	for my $token (@$cmd) {
+		goto DONE if $token =~ /\$\?/;
+	}
+
 	# flag missing "&&" at end of previous command
 	my $n = find_non_nl($tokens);
 	splice(@$tokens, $n + 1, 0, '?!AMP?!') unless $n < 0;
diff --git a/t/chainlint/chain-break-status.expect b/t/chainlint/chain-break-status.expect
new file mode 100644
index 00000000000..f4bada94632
--- /dev/null
+++ b/t/chainlint/chain-break-status.expect
@@ -0,0 +1,9 @@
+OUT=$(( ( large_git ; echo $? 1 >& 3 ) | : ) 3 >& 1) &&
+test_match_signal 13 "$OUT" &&
+
+{ test-tool sigchain > actual ; ret=$? ; } &&
+{
+	test_match_signal 15 "$ret" ||
+	test "$ret" = 3
+} &&
+test_cmp expect actual
diff --git a/t/chainlint/chain-break-status.test b/t/chainlint/chain-break-status.test
new file mode 100644
index 00000000000..a6602a7b99c
--- /dev/null
+++ b/t/chainlint/chain-break-status.test
@@ -0,0 +1,11 @@
+# LINT: broken &&-chain okay if next command handles "$?" explicitly
+OUT=$( ((large_git; echo $? 1>&3) | :) 3>&1 ) &&
+test_match_signal 13 "$OUT" &&
+
+# LINT: broken &&-chain okay if next command handles "$?" explicitly
+{ test-tool sigchain >actual; ret=$?; } &&
+{
+	test_match_signal 15 "$ret" ||
+	test "$ret" = 3
+} &&
+test_cmp expect actual
-- 
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