chainlint.pl: don't flag broken &&-chain if failure indicated explicitly

There are quite a few tests which print an error messages and then
explicitly signal failure with `false`, `return 1`, or `exit 1` as the
final command in an `if` branch. In these cases, the tests don't bother
maintaining the &&-chain between `echo` and the explicit "test failed"
indicator. Since such constructs are manually signaling failure, their
&&-chain breakage is legitimate and safe -- both for the command
immediately preceding `false`, `return`, or `exit`, as well as for all
preceding commands in the `if` branch. Therefore, stop flagging &&-chain
breakage in these sorts of cases.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

7 files changed, 62 insertions, 2 deletions

diff --git a/t/chainlint.pl b/t/chainlint.pl
index 14e1db3519..a76a09ecf5 100755
--- a/t/chainlint.pl
+++ b/t/chainlint.pl
@@ -503,6 +503,14 @@ sub accumulate {
 		goto DONE if $token =~ /\$\?/;
 	}
 
+	# if this command is "false", "return 1", or "exit 1" (which signal
+	# failure explicitly), then okay for all preceding commands to be
+	# missing "&&"
+	if ($$cmd[0] =~ /^(?:false|return|exit)$/) {
+		@$tokens = grep(!/^\?!AMP\?!$/, @$tokens);
+		goto DONE;
+	}
+
 	# flag missing "&&" at end of previous command
 	my $n = find_non_nl($tokens);
 	splice(@$tokens, $n + 1, 0, '?!AMP?!') unless $n < 0;
diff --git a/t/chainlint/chain-break-false.expect b/t/chainlint/chain-break-false.expect
new file mode 100644
index 0000000000..989766fb85
--- /dev/null
+++ b/t/chainlint/chain-break-false.expect
@@ -0,0 +1,9 @@
+if condition not satisified
+then
+	echo it did not work...
+	echo failed!
+	false
+else
+	echo it went okay ?!AMP?!
+	congratulate user
+fi
diff --git a/t/chainlint/chain-break-false.test b/t/chainlint/chain-break-false.test
new file mode 100644
index 0000000000..a5aaff8c8a
--- /dev/null
+++ b/t/chainlint/chain-break-false.test
@@ -0,0 +1,10 @@
+# LINT: broken &&-chain okay if explicit "false" signals failure
+if condition not satisified
+then
+	echo it did not work...
+	echo failed!
+	false
+else
+	echo it went okay
+	congratulate user
+fi
diff --git a/t/chainlint/chain-break-return-exit.expect b/t/chainlint/chain-break-return-exit.expect
index dba292ee89..1732d221c3 100644
--- a/t/chainlint/chain-break-return-exit.expect
+++ b/t/chainlint/chain-break-return-exit.expect
@@ -1,3 +1,18 @@
+case "$(git ls-files)" in
+one ) echo pass one ;;
+* ) echo bad one ; return 1 ;;
+esac &&
+(
+	case "$(git ls-files)" in
+	two ) echo pass two ;;
+	* ) echo bad two ; exit 1 ;;
+esac
+) &&
+case "$(git ls-files)" in
+dir/two"$LF"one ) echo pass both ;;
+* ) echo bad ; return 1 ;;
+esac &&
+
 for i in 1 2 3 4 ; do
 	git checkout main -b $i || return $?
 	test_commit $i $i $i tag$i || return $?
diff --git a/t/chainlint/chain-break-return-exit.test b/t/chainlint/chain-break-return-exit.test
index e2b059933a..46542edf88 100644
--- a/t/chainlint/chain-break-return-exit.test
+++ b/t/chainlint/chain-break-return-exit.test
@@ -1,3 +1,21 @@
+case "$(git ls-files)" in
+one) echo pass one ;;
+# LINT: broken &&-chain okay if explicit "return 1" signals failuire
+*) echo bad one; return 1 ;;
+esac &&
+(
+	case "$(git ls-files)" in
+	two) echo pass two ;;
+# LINT: broken &&-chain okay if explicit "exit 1" signals failuire
+	*) echo bad two; exit 1 ;;
+	esac
+) &&
+case "$(git ls-files)" in
+dir/two"$LF"one) echo pass both ;;
+# LINT: broken &&-chain okay if explicit "return 1" signals failuire
+*) echo bad; return 1 ;;
+esac &&
+
 for i in 1 2 3 4 ; do
 # LINT: broken &&-chain okay if explicit "return $?" signals failure
 	git checkout main -b $i || return $?
diff --git a/t/chainlint/if-in-loop.expect b/t/chainlint/if-in-loop.expect
index 03b82a3e58..d6514ae749 100644
--- a/t/chainlint/if-in-loop.expect
+++ b/t/chainlint/if-in-loop.expect
@@ -3,7 +3,7 @@
 	do
 		if false
 		then
-			echo "err" ?!AMP?!
+			echo "err"
 			exit 1
 		fi ?!AMP?!
 		foo
diff --git a/t/chainlint/if-in-loop.test b/t/chainlint/if-in-loop.test
index f0cf19cfad..90c23976fe 100644
--- a/t/chainlint/if-in-loop.test
+++ b/t/chainlint/if-in-loop.test
@@ -3,7 +3,7 @@
 	do
 		if false
 		then
-# LINT: missing "&&" on "echo"
+# LINT: missing "&&" on "echo" okay since "exit 1" signals error explicitly
 			echo "err"
 			exit 1
 # LINT: missing "&&" on "fi"