From af3570ed6ca97605d62ebe1836fc893014ae844b Mon Sep 17 00:00:00 2001
From: Jeff King <peff@peff.net>
Date: Sat, 3 Mar 2018 00:58:10 -0500
Subject: t3701: add a test for interactive.diffFilter

This feature was added in 01143847db (add--interactive:
allow custom diff highlighting programs, 2016-02-27) but
never tested. Let's add a basic test.

Note that we only apply the filter when color is enabled,
so we have to use test_terminal. This is an open limitation
explicitly mentioned in the original commit. So take this
commit as testing the status quo, and not making a statement
on whether we'd want to enhance that in the future.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 058698d..64fe56c 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -392,6 +392,18 @@ test_expect_success TTY 'diffs can be colorized' '
 	grep "$(printf "\\033")" output
 '
 
+test_expect_success TTY 'diffFilter filters diff' '
+	git reset --hard &&
+
+	echo content >test &&
+	test_config interactive.diffFilter "sed s/^/foo:/" &&
+	printf y | test_terminal git add -p >output 2>&1 &&
+
+	# avoid depending on the exact coloring or content of the prompts,
+	# and just make sure we saw our diff prefixed
+	grep foo:.*content output
+'
+
 test_expect_success 'patch-mode via -i prompts for files' '
 	git reset --hard &&
 
-- 
cgit v0.10.2-6-g49f6


From 42f7d45428e260acf535ba0d55ecc91ee81e21da Mon Sep 17 00:00:00 2001
From: Jeff King <peff@peff.net>
Date: Sat, 3 Mar 2018 00:58:49 -0500
Subject: add--interactive: detect bogus diffFilter output

It's important that the diff-filter only filter the
individual lines, and that there remain a one-to-one mapping
between the input and output lines. Otherwise, things like
hunk-splitting will behave quite unexpectedly (e.g., you
think you are splitting at one point, but it has a different
effect in the text patch we apply).

We can't detect all problematic cases, but we can at least
catch the obvious case where we don't even have the correct
number of lines.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index 964c3a7..ff02008 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -705,6 +705,14 @@ sub parse_diff {
 	}
 	my (@hunk) = { TEXT => [], DISPLAY => [], TYPE => 'header' };
 
+	if (@colored && @colored != @diff) {
+		print STDERR
+		  "fatal: mismatched output from interactive.diffFilter\n",
+		  "hint: Your filter must maintain a one-to-one correspondence\n",
+		  "hint: between its input and output lines.\n";
+		exit 1;
+	}
+
 	for (my $i = 0; $i < @diff; $i++) {
 		if ($diff[$i] =~ /^@@ /) {
 			push @hunk, { TEXT => [], DISPLAY => [],
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 64fe56c..9bb17f9 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -404,6 +404,14 @@ test_expect_success TTY 'diffFilter filters diff' '
 	grep foo:.*content output
 '
 
+test_expect_success TTY 'detect bogus diffFilter output' '
+	git reset --hard &&
+
+	echo content >test &&
+	test_config interactive.diffFilter "echo too-short" &&
+	printf y | test_must_fail test_terminal git add -p
+'
+
 test_expect_success 'patch-mode via -i prompts for files' '
 	git reset --hard &&
 
-- 
cgit v0.10.2-6-g49f6