rebase -i: highlight problems with core.commentchar

The interactive rebase does not currently play well with
core.commentchar. Let's add some tests to highlight those problems
that will be fixed in the remainder of the series.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t0030-stripspace.sh

@@ -432,6 +432,15 @@ test_expect_success '-c with changed comment char' '
 	test_cmp expect actual
 '
 
+test_expect_failure '-c with comment char defined in .git/config' '
+	test_config core.commentchar = &&
+	printf "= foo\n" >expect &&
+	printf "foo" | (
+		mkdir sub && cd sub && git stripspace -c
+	) >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'avoid SP-HT sequence in commented line' '
 	printf "#\tone\n#\n# two\n" >expect &&
 	printf "\tone\n\ntwo\n" | git stripspace -c >actual &&

t/t3404-rebase-interactive.sh

@@ -983,6 +983,17 @@ test_expect_success 'rebase -i respects core.commentchar' '
 	test B = $(git cat-file commit HEAD^ | sed -ne \$p)
 '
 
+test_expect_failure 'rebase -i respects core.commentchar=auto' '
+	test_config core.commentchar auto &&
+	write_script copy-edit-script.sh <<-\EOF &&
+	cp "$1" edit-script
+	EOF
+	test_set_editor "$(pwd)/copy-edit-script.sh" &&
+	test_when_finished "git rebase --abort || :" &&
+	git rebase -i HEAD^ &&
+	test -z "$(grep -ve "^#" -e "^\$" -e "^pick" edit-script)"
+'
+
 test_expect_success 'rebase -i, with <onto> and <upstream> specified as :/quuxery' '
 	test_when_finished "git branch -D torebase" &&
 	git checkout -b torebase branch1 &&