fast-import: prevent producing bad delta

diff --git a/sha1_file.c b/sha1_file.c
index 064a33040812ba8782bf602c693abf08613d6ec7..697f4a43c5ef0bdc220a15545d94bc31ad1f248e 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1205,20 +1205,29 @@ static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
        return map;
 }
 
-static int legacy_loose_object(unsigned char *map)
+/*
+ * There used to be a second loose object header format which
+ * was meant to mimic the in-pack format, allowing for direct
+ * copy of the object data.  This format turned up not to be
+ * really worth it and we no longer write loose objects in that
+ * format.
+ */
+static int experimental_loose_object(unsigned char *map)
 {
        unsigned int word;
 
        /*
         * Is it a zlib-compressed buffer? If so, the first byte
         * must be 0x78 (15-bit window size, deflated), and the
-        * first 16-bit word is evenly divisible by 31
+        * first 16-bit word is evenly divisible by 31. If so,
+        * we are looking at the official format, not the experimental
+        * one.
         */
        word = (map[0] << 8) + map[1];
        if (map[0] == 0x78 && !(word % 31))
-               return 1;
-       else
                return 0;
+       else
+               return 1;
 }
 
 unsigned long unpack_object_header_buffer(const unsigned char *buf,
@@ -1262,34 +1271,29 @@ static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned lon
        stream->next_out = buffer;
        stream->avail_out = bufsiz;
 
-       if (legacy_loose_object(map)) {
-               git_inflate_init(stream);
-               return git_inflate(stream, 0);
-       }
-
+       if (experimental_loose_object(map)) {
+               /*
+                * The old experimental format we no longer produce;
+                * we can still read it.
+                */
+               used = unpack_object_header_buffer(map, mapsize, &type, &size);
+               if (!used || !valid_loose_object_type[type])
+                       return -1;
+               map += used;
+               mapsize -= used;
 
-       /*
-        * There used to be a second loose object header format which
-        * was meant to mimic the in-pack format, allowing for direct
-        * copy of the object data.  This format turned up not to be
-        * really worth it and we don't write it any longer.  But we
-        * can still read it.
-        */
-       used = unpack_object_header_buffer(map, mapsize, &type, &size);
-       if (!used || !valid_loose_object_type[type])
-               return -1;
-       map += used;
-       mapsize -= used;
+               /* Set up the stream for the rest.. */
+               stream->next_in = map;
+               stream->avail_in = mapsize;
+               git_inflate_init(stream);
 
-       /* Set up the stream for the rest.. */
-       stream->next_in = map;
-       stream->avail_in = mapsize;
+               /* And generate the fake traditional header */
+               stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
+                                                typename(type), size);
+               return 0;
+       }
        git_inflate_init(stream);
-
-       /* And generate the fake traditional header */
-       stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
-                                        typename(type), size);
-       return 0;
+       return git_inflate(stream, 0);
 }
 
 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)