tags: support reading tags cache without populating
authorGregory Szorc <gregory.szorc@gmail.com>
Mon, 25 May 2015 16:24:23 -0700
changeset 25380 eaa456c5e699
parent 25379 894bcdbb9e7a
child 25381 47edeff19139
tags: support reading tags cache without populating An upcoming patch will teach the bundle2 protocol to transfer .hgtags fnodes to the client. We don't want this to incur any extra work at serve time. Create an optional cache query mode that doesn't populate the cache as a side-effect.
mercurial/tags.py
--- a/mercurial/tags.py	Sun May 31 17:41:35 2015 -0700
+++ b/mercurial/tags.py	Mon May 25 16:24:23 2015 -0700
@@ -442,11 +442,13 @@
                 self._raw.pop()
             self._dirtyoffset = len(self._raw)
 
-    def getfnode(self, node):
+    def getfnode(self, node, computemissing=True):
         """Obtain the filenode of the .hgtags file at a specified revision.
 
         If the value is in the cache, the entry will be validated and returned.
-        Otherwise, the filenode will be computed and returned.
+        Otherwise, the filenode will be computed and returned unless
+        "computemissing" is False, in which case None will be returned without
+        any potentially expensive computation being performed.
 
         If an .hgtags does not exist at the specified revision, nullid is
         returned.
@@ -470,7 +472,12 @@
 
             # Fall through.
 
-        # If we get here, the entry is either missing or invalid. Populate it.
+        # If we get here, the entry is either missing or invalid.
+
+        if not computemissing:
+            return None
+
+        # Populate missing entry.
         try:
             fnode = ctx.filenode('.hgtags')
         except error.LookupError: