Differences From:

File src/checkin.c part of check-in [8d5ab7913e] - Do not print a warning about "a fork has occurred" when checking in to a leaf that is also the basis of a branch. by drh on 2009-01-21 03:12:14. [view]

To:

File src/checkin.c part of check-in [faf09dc7ae] - Define a "leaf" as a check-in with no children in the same branch. The is_a_leaf() function does some complicated SQL to figure this out. by drh on 2009-01-22 01:53:04. [view]

@@ -347,24 +347,43 @@
   }
 }
 
 /*
-** Return true if the check-in with RID=rid has no child
-** check-ins which are not tagged with "newbranch".  In other words,
-** return true if the check-in is a leaf.
+** Return true if the check-in with RID=rid is a leaf.
+**
+** A leaf has no children in the same branch.  For the purposes of
+** this definition, a two check-ins are in same branch they have the
+** same set of propagated symbolic tags.
 */
 int is_a_leaf(int rid){
-  return !db_exists(
-    "SELECT 1 FROM plink"
-    " WHERE pid=%d"
-      " AND NOT EXISTS("
-                     "SELECT 1 FROM tagxref"
-                     " WHERE tagxref.rid=plink.cid"
-                     "   AND tagxref.tagid=%d"
-                     "   AND tagxref.tagtype=1"
-               ")",
-    rid, TAG_NEWBRANCH
-  );
+
+  /* This query selects all children in the same branch as rid */
+  static const char zSql[] =
+    @ SELECT cid FROM plink
+    @  WHERE pid=:rid
+    @    AND (SELECT group_concat(x) FROM (
+    @           SELECT tag.tagid AS x FROM tagxref, tag
+    @            WHERE tagxref.rid=:rid AND tagxref.tagtype=2
+    @              AND tag.tagid=tagxref.tagid AND tagxref.srcid=0
+    @              AND tag.tagname GLOB 'sym-*'
+    @            ORDER BY 1)
+    @        ) ==
+    @        (SELECT group_concat(x) FROM (
+    @           SELECT tag.tagid AS x FROM tagxref, tag
+    @            WHERE tagxref.rid=plink.cid AND tagxref.tagtype=2
+    @              AND tag.tagid=tagxref.tagid
+    @              AND tag.tagname GLOB 'sym-*'
+    @            ORDER BY 1)
+    @        )
+  ;
+  Stmt q;    /* The prepared statement */
+  int rc;    /* Return code from stepping the prepared statement */
+
+  db_prepare(&q, zSql);
+  db_bind_int(&q, ":rid", rid);
+  rc = db_step(&q);
+  db_finalize(&q);
+  return rc==SQLITE_DONE;
 }
 
 /*
 ** COMMAND: ci