Teach "diff --check" about new blank lines at end

When a patch adds new blank lines at the end, "git apply --whitespace"
warns.  This teaches "diff --check" to do the same.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index 3dfa53c5668fda37bfce453d381445e5269fb979..188428dd26b7d9bf8dc0b9cd1a02ebca6d459400 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -823,6 +823,7 @@ extern unsigned ws_check(const char *line, int len, unsigned ws_rule);
 extern void ws_check_emit(const char *line, int len, unsigned ws_rule, FILE *stream, const char *set, const char *reset, const char *ws);
 extern char *whitespace_error_string(unsigned ws);
 extern int ws_fix_copy(char *, const char *, int, unsigned, int *);
+extern int ws_blank_line(const char *line, int len, unsigned ws_rule);
 
 /* ls-files */
 int pathspec_match(const char **spec, char *matched, const char *filename, int skiplen);

diff --git a/diff.c b/diff.c
index 6bcbe2082873c7f311931890d39afdbd5345838d..f31c7211683802844f9aab3e86105695a17f79e5 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -1140,6 +1140,7 @@ struct checkdiff_t {
        struct diff_options *o;
        unsigned ws_rule;
        unsigned status;
+       int trailing_blanks_start;
 };
 
 static void checkdiff_consume(void *priv, char *line, unsigned long len)
@@ -1154,6 +1155,10 @@ static void checkdiff_consume(void *priv, char *line, unsigned long len)
        if (line[0] == '+') {
                unsigned bad;
                data->lineno++;
+               if (!ws_blank_line(line + 1, len - 1, data->ws_rule))
+                       data->trailing_blanks_start = 0;
+               else if (!data->trailing_blanks_start)
+                       data->trailing_blanks_start = data->lineno;
                bad = ws_check(line + 1, len - 1, data->ws_rule);
                if (!bad)
                        return;
@@ -1165,14 +1170,16 @@ static void checkdiff_consume(void *priv, char *line, unsigned long len)
                emit_line(data->o->file, set, reset, line, 1);
                ws_check_emit(line + 1, len - 1, data->ws_rule,
                              data->o->file, set, reset, ws);
-       } else if (line[0] == ' ')
+       } else if (line[0] == ' ') {
                data->lineno++;
-       else if (line[0] == '@') {
+               data->trailing_blanks_start = 0;
+       } else if (line[0] == '@') {
                char *plus = strchr(line, '+');
                if (plus)
                        data->lineno = strtol(plus, NULL, 10) - 1;
                else
                        die("invalid diff");
+               data->trailing_blanks_start = 0;
        }
 }
 
@@ -1584,6 +1591,12 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
                ecb.outf = xdiff_outf;
                ecb.priv = &data;
                xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
+
+               if (data.trailing_blanks_start) {
+                       fprintf(o->file, "%s:%d: ends with blank lines.\n",
+                               data.filename, data.trailing_blanks_start);
+                       data.status = 1; /* report errors */
+               }
        }
  free_and_return:
        diff_free_filespec_data(one);

diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index b7cc6b28e61e73af3206a9613620a635a467ea0e..0922c708f16fea490a85d16d5d4d366df0fb2088 100755 (executable)
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -335,4 +335,10 @@ test_expect_success 'line numbers in --check output are correct' '
 
 '
 
+test_expect_success 'checkdiff detects trailing blank lines' '
+       echo "foo();" >x &&
+       echo "" >>x &&
+       git diff --check | grep "ends with blank"
+'
+
 test_done

diff --git a/ws.c b/ws.c
index 24d3e3de078c699ca6bb0dfd524c097bf220b4b2..7a7ff130a34942506e6068105ac5946c9404bf18 100644 (file)
--- a/ws.c
+++ b/ws.c
@@ -225,6 +225,21 @@ unsigned ws_check(const char *line, int len, unsigned ws_rule)
        return ws_check_emit_1(line, len, ws_rule, NULL, NULL, NULL, NULL);
 }
 
+int ws_blank_line(const char *line, int len, unsigned ws_rule)
+{
+       /*
+        * We _might_ want to treat CR differently from other
+        * whitespace characters when ws_rule has WS_CR_AT_EOL, but
+        * for now we just use this stupid definition.
+        */
+       while (len-- > 0) {
+               if (!isspace(*line))
+                       return 0;
+               line++;
+       }
+       return 1;
+}
+
 /* Copy the line to the buffer while fixing whitespaces */
 int ws_fix_copy(char *dst, const char *src, int len, unsigned ws_rule, int *error_count)
 {