fast-export: Add a --tag-of-filtered-object option for newly dangling tags

diff --git a/builtin-fast-export.c b/builtin-fast-export.c
index 9b8bd3729039ebce318c74eb7d873d8e4ff6c178..dc2c6ab173972f408641f4376e0817c29b3321ef 100644 (file)
--- a/builtin-fast-export.c
+++ b/builtin-fast-export.c
@@ -23,7 +23,8 @@ static const char *fast_export_usage[] = {
 };
 
 static int progress;
-static enum { VERBATIM, WARN, STRIP, ABORT } signed_tag_mode = ABORT;
+static enum { ABORT, VERBATIM, WARN, STRIP } signed_tag_mode = ABORT;
+static enum { ERROR, DROP, REWRITE } tag_of_filtered_mode = ABORT;
 static int fake_missing_tagger;
 
 static int parse_opt_signed_tag_mode(const struct option *opt,
@@ -42,6 +43,20 @@ static int parse_opt_signed_tag_mode(const struct option *opt,
        return 0;
 }
 
+static int parse_opt_tag_of_filtered_mode(const struct option *opt,
+                                         const char *arg, int unset)
+{
+       if (unset || !strcmp(arg, "abort"))
+               tag_of_filtered_mode = ABORT;
+       else if (!strcmp(arg, "drop"))
+               tag_of_filtered_mode = DROP;
+       else if (!strcmp(arg, "rewrite"))
+               tag_of_filtered_mode = REWRITE;
+       else
+               return error("Unknown tag-of-filtered mode: %s", arg);
+       return 0;
+}
+
 static struct decoration idnums;
 static uint32_t last_idnum;
 
@@ -290,6 +305,8 @@ static void handle_tag(const char *name, struct tag *tag)
        const char *tagger, *tagger_end, *message;
        size_t message_size = 0;
        struct object *tagged;
+       int tagged_mark;
+       struct commit *p;
 
        /* Trees have no identifer in fast-export output, thus we have no way
         * to output tags of trees, tags of tags of trees, etc.  Simply omit
@@ -348,10 +365,45 @@ static void handle_tag(const char *name, struct tag *tag)
                        }
        }
 
+       /* handle tag->tagged having been filtered out due to paths specified */
+       tagged = tag->tagged;
+       tagged_mark = get_object_mark(tagged);
+       if (!tagged_mark) {
+               switch(tag_of_filtered_mode) {
+               case ABORT:
+                       die ("Tag %s tags unexported object; use "
+                            "--tag-of-filtered-object=<mode> to handle it.",
+                            sha1_to_hex(tag->object.sha1));
+               case DROP:
+                       /* Ignore this tag altogether */
+                       return;
+               case REWRITE:
+                       if (tagged->type != OBJ_COMMIT) {
+                               die ("Tag %s tags unexported %s!",
+                                    sha1_to_hex(tag->object.sha1),
+                                    typename(tagged->type));
+                       }
+                       p = (struct commit *)tagged;
+                       for (;;) {
+                               if (p->parents && p->parents->next)
+                                       break;
+                               if (p->object.flags & UNINTERESTING)
+                                       break;
+                               if (!(p->object.flags & TREESAME))
+                                       break;
+                               if (!p->parents)
+                                       die ("Can't find replacement commit for tag %s\n",
+                                            sha1_to_hex(tag->object.sha1));
+                               p = p->parents->item;
+                       }
+                       tagged_mark = get_object_mark(&p->object);
+               }
+       }
+
        if (!prefixcmp(name, "refs/tags/"))
                name += 10;
        printf("tag %s\nfrom :%d\n%.*s%sdata %d\n%.*s\n",
-              name, get_object_mark(tag->tagged),
+              name, tagged_mark,
               (int)(tagger_end - tagger), tagger,
               tagger == tagger_end ? "" : "\n",
               (int)message_size, (int)message_size, message ? message : "");
@@ -513,6 +565,9 @@ int cmd_fast_export(int argc, const char **argv, const char *prefix)
                OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, "mode",
                             "select handling of signed tags",
                             parse_opt_signed_tag_mode),
+               OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, "mode",
+                            "select handling of tags that tag filtered objects",
+                            parse_opt_tag_of_filtered_mode),
                OPT_STRING(0, "export-marks", &export_filename, "FILE",
                             "Dump marks to this file"),
                OPT_STRING(0, "import-marks", &import_filename, "FILE",