diff: handle lines containing only whitespace and tabs better

When a line contains nothing but whitespace with at least one tab
and the core.whitespace config option contains blank-at-eol, the
whitespace on the line is being printed twice, once unhighlighted
(unless otherwise matched by one of the other core.whitespace values),
and a second time highlighted for blank-at-eol.

Update the leading indentation check to stop checking when it reaches
the trailing whitespace.

Signed-off-by: Kevin Ballard <kevin@sb.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index 935d101fe8d880ff426452ca6f611ce8d30b8bc1..a8736f7cbeef65b3454847bb4b4df508c0079652 100755 (executable)
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -491,4 +491,41 @@ test_expect_success 'combined diff with autocrlf conversion' '
 
 '
 
+# Start testing the colored format for whitespace checks
+
+test_expect_success 'setup diff colors' '
+       git config color.diff always &&
+       git config color.diff.plain normal &&
+       git config color.diff.meta bold &&
+       git config color.diff.frag cyan &&
+       git config color.diff.func normal &&
+       git config color.diff.old red &&
+       git config color.diff.new green &&
+       git config color.diff.commit yellow &&
+       git config color.diff.whitespace "normal red" &&
+
+       git config core.autocrlf false
+'
+cat >expected <<\EOF
+<BOLD>diff --git a/x b/x<RESET>
+<BOLD>index 9daeafb..2874b91 100644<RESET>
+<BOLD>--- a/x<RESET>
+<BOLD>+++ b/x<RESET>
+<CYAN>@@ -1 +1,4 @@<RESET>
+ test<RESET>
+<GREEN>+<RESET><GREEN>{<RESET>
+<GREEN>+<RESET><BRED>  <RESET>
+<GREEN>+<RESET><GREEN>}<RESET>
+EOF
+
+test_expect_success 'diff that introduces a line with only tabs' '
+       git config core.whitespace blank-at-eol &&
+       git reset --hard &&
+       echo "test" > x &&
+       git commit -m "initial" x &&
+       echo "{NTN}" | tr "NT" "\n\t" >> x &&
+       git -c color.diff=always diff | test_decode_color >current &&
+       test_cmp expected current
+'
+
 test_done

diff --git a/ws.c b/ws.c
index d7b8c33f14195ba7ebe86bdbca2fea8f1b22ad37..7302f8f5a2cd450771aefcba0a385a90121ba0cf 100644 (file)
--- a/ws.c
+++ b/ws.c
@@ -174,8 +174,11 @@ static unsigned ws_check_emit_1(const char *line, int len, unsigned ws_rule,
                }
        }
 
+       if (trailing_whitespace == -1)
+               trailing_whitespace = len;
+
        /* Check indentation */
-       for (i = 0; i < len; i++) {
+       for (i = 0; i < trailing_whitespace; i++) {
                if (line[i] == ' ')
                        continue;
                if (line[i] != '\t')
@@ -218,8 +221,6 @@ static unsigned ws_check_emit_1(const char *line, int len, unsigned ws_rule,
                 * Now the rest of the line starts at "written".
                 * The non-highlighted part ends at "trailing_whitespace".
                 */
-               if (trailing_whitespace == -1)
-                       trailing_whitespace = len;
 
                /* Emit non-highlighted (middle) segment. */
                if (trailing_whitespace - written > 0) {