patch 8.1.0502: internal diff fails when diffing a context diffv8.1.0502

Problem:    Internal diff fails when diffing a context diff. (Hirohito Higashi)
Solution:   Only use callback calls with one line. (closes #3581)

1 files changed, 15 insertions, 13 deletions

diff --git a/src/diff.c b/src/diff.c
index 23503d8266..c001761340 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -3206,21 +3206,23 @@ parse_diff_unified(
 xdiff_out(void *priv, mmbuffer_t *mb, int nbuf)
 {
     diffout_T	*dout = (diffout_T *)priv;
-    int		i;
     char_u	*p;
 
-    for (i = 0; i < nbuf; i++)
-    {
-	// We are only interested in the header lines, skip text lines.
-	if (STRNCMP(mb[i].ptr, "@@ ", 3)  != 0)
-	    continue;
-	if (ga_grow(&dout->dout_ga, 1) == FAIL)
-	    return -1;
-	p = vim_strnsave((char_u *)mb[i].ptr, mb[i].size);
-	if (p == NULL)
-	    return -1;
-	((char_u **)dout->dout_ga.ga_data)[dout->dout_ga.ga_len++] = p;
-    }
+    // The header line always comes by itself, text lines in at least two
+    // parts.  We drop the text part.
+    if (nbuf > 1)
+	return 0;
+
+    // sanity check
+    if (STRNCMP(mb[0].ptr, "@@ ", 3)  != 0)
+	return 0;
+
+    if (ga_grow(&dout->dout_ga, 1) == FAIL)
+	return -1;
+    p = vim_strnsave((char_u *)mb[0].ptr, mb[0].size);
+    if (p == NULL)
+	return -1;
+    ((char_u **)dout->dout_ga.ga_data)[dout->dout_ga.ga_len++] = p;
     return 0;
 }