From: Andreas Gruenbacher <agruen@suse.de>
Subject: diff3-style merges: include filenames

Include the filenames from the patch header in the diff3-style format.
Use the name of the output file as the third filename.

	<<<<<<< old-filename
	old lines from patch
	||||||| new-filename
	new lines from patch
	=======
	merge result
	>>>>>>> output-filename

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>

---
 patch.c |   21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

Index: b/patch.c
===================================================================
--- a/patch.c
+++ b/patch.c
@@ -1353,6 +1353,7 @@ static bool merge_hunk (struct outstate 
     register LINENUM merge, merge_end;
     register FILE *fp = outstate->ofp;
     bool succeeded = true;
+    const char *name;
 
     while (pch_char(new) == '=' || pch_char(new) == '\n' /* ??? */)
 	new++;
@@ -1410,7 +1411,11 @@ static bool merge_hunk (struct outstate 
     }
 
     /* "From" lines in the patch */
-    fprintf(fp, outstate->after_newline + "\n<<<<<<<\n");
+    name = pch_name(OLD);
+    if (!name)
+      name = "";
+    fprintf(fp, outstate->after_newline + "\n<<<<<<<%*s\n",
+    	    strlen(name) ? strlen(name) + 1 : 0, name);
     if (ferror (fp))
       write_fatal ();
     outstate->after_newline = true;
@@ -1421,7 +1426,11 @@ static bool merge_hunk (struct outstate 
 
     if (fuzz) {
 	/* "To" lines in the patch */
-	fprintf(fp, outstate->after_newline + "\n|||||||\n");
+	name = pch_name(NEW);
+	if (!name)
+	  name = "";
+	fprintf(fp, outstate->after_newline + "\n|||||||%*s\n",
+	        strlen(name) ? strlen(name) + 1 : 0, name);
 	if (ferror (fp))
 	  write_fatal ();
 	outstate->after_newline = true;
@@ -1442,7 +1451,13 @@ static bool merge_hunk (struct outstate 
 		    copy_till(outstate, merge_end);
     }
 
-    fprintf(fp, outstate->after_newline + "\n>>>>>>>\n");
+    /* If the merge result and the new file are the same, label the merge
+       result with the new file's name. */
+    name = fuzz ? NULL : pch_name(NEW);
+    if (!name)
+      name = "";
+    fprintf(fp, outstate->after_newline + "\n>>>>>>>%*s\n",
+	    strlen(name) ? strlen(name) + 1 : 0, name);
     if (ferror (fp))
       write_fatal ();
     outstate->after_newline = true;