blame: prevent error if range ends past end of file

If the -L option is used to specify a line range in git blame, and the
end of the range is past the end of the file, git will fail with a fatal
error. This commit prevents such behavior - instead we display the blame
for existing lines within the specified range. Tests are amended
accordingly.

This commit also fixes two corner cases. Blaming -L n,-(n+1) now blames
the first n lines of a file rather than from n to the end of the file.
Blaming -L ,-n will be treated as -L 1,-n and blame the first line of
the file, rather than blaming the whole file.

Signed-off-by: Isabella Stephens <istephens@atlassian.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/t/t8003-blame-corner-cases.sh b/t/t8003-blame-corner-cases.sh
index 661f9d430d..c92a47b6d5 100755
--- a/t/t8003-blame-corner-cases.sh
+++ b/t/t8003-blame-corner-cases.sh
@@ -216,14 +216,18 @@ test_expect_success 'blame -L with invalid start' '
 '
 
 test_expect_success 'blame -L with invalid end' '
-	test_must_fail git blame -L1,5 tres 2>errors &&
-	test_i18ngrep "has only 2 lines" errors
+	git blame -L1,5 tres >out &&
+	test_line_count = 2 out
 '
 
 test_expect_success 'blame parses <end> part of -L' '
 	git blame -L1,1 tres >out &&
-	cat out &&
-	test $(wc -l < out) -eq 1
+	test_line_count = 1 out
+'
+
+test_expect_success 'blame -Ln,-(n+1)' '
+	git blame -L3,-4 nine_lines >out &&
+	test_line_count = 3 out
 '
 
 test_expect_success 'indent of line numbers, nine lines' '