Merge branch 'jm/maint-diff-words-with-sbe'

* jm/maint-diff-words-with-sbe:
  do not read beyond end of malloc'd buffer

2 files changed, 36 insertions, 2 deletions

diff --git a/diff.c b/diff.c
index ba5f7aa217..8f4815bfd7 100644
--- a/diff.c
+++ b/diff.c
@@ -1117,8 +1117,16 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 			emit_line(ecbdata->opt, plain, reset, line, len);
 			fputs("~\n", ecbdata->opt->file);
 		} else {
-			/* don't print the prefix character */
-			emit_line(ecbdata->opt, plain, reset, line+1, len-1);
+			/*
+			 * Skip the prefix character, if any.  With
+			 * diff_suppress_blank_empty, there may be
+			 * none.
+			 */
+			if (line[0] != '\n') {
+			      line++;
+			      len--;
+			}
+			emit_line(ecbdata->opt, plain, reset, line, len);
 		}
 		return;
 	}
diff --git a/t/t4034-diff-words.sh b/t/t4034-diff-words.sh
index 37aeab0d5c..c374aa4c1c 100755
--- a/t/t4034-diff-words.sh
+++ b/t/t4034-diff-words.sh
@@ -307,4 +307,30 @@ test_language_driver python
 test_language_driver ruby
 test_language_driver tex
 
+test_expect_success 'word-diff with diff.sbe' '
+	cat >expect <<-\EOF &&
+	diff --git a/pre b/post
+	index a1a53b5..bc8fe6d 100644
+	--- a/pre
+	+++ b/post
+	@@ -1,3 +1,3 @@
+	a
+
+	[-b-]{+c+}
+	EOF
+	cat >pre <<-\EOF &&
+	a
+
+	b
+	EOF
+	cat >post <<-\EOF &&
+	a
+
+	c
+	EOF
+	test_when_finished "git config --unset diff.suppress-blank-empty" &&
+	git config diff.suppress-blank-empty true &&
+	word_diff --word-diff=plain
+'
+
 test_done