dirstate: change placeholder hash length to 20 bytes
authorDurham Goode <durham@fb.com>
Thu, 10 Nov 2016 02:17:22 -0800
changeset 30360 0298a07f64d9
parent 30359 673f0fdc1046
child 30361 1070df141718
dirstate: change placeholder hash length to 20 bytes Previously the new-node placeholder hash for manifests generated from the dirstate was a 21byte long string of "!" characters. Normal hashes are only 20 bytes long. This makes it complicated to implement more efficient manifest implementations which rely on the hashes being fixed length. Let's change this hash to just be 20 bytes long, and rely on the astronomical improbability of an actual hash being 20 "!" bytes in a row (just like we rely on no hash ever being the nullid). A future diff will do this for added and modified dirstate markers as well, so we're putting the new newnodeid in node.py so there's a common place for these placeholders.
mercurial/context.py
mercurial/copies.py
mercurial/node.py
--- a/mercurial/context.py	Mon Nov 07 18:57:54 2016 -0800
+++ b/mercurial/context.py	Thu Nov 10 02:17:22 2016 -0800
@@ -16,6 +16,7 @@
 from .node import (
     bin,
     hex,
+    newnodeid,
     nullid,
     nullrev,
     short,
@@ -39,11 +40,6 @@
 
 propertycache = util.propertycache
 
-# Phony node value to stand-in for new files in some uses of
-# manifests. Manifests support 21-byte hashes for nodes which are
-# dirty in the working copy.
-_newnode = '!' * 21
-
 nonascii = re.compile(r'[^\x21-\x7f]').search
 
 class basectx(object):
@@ -142,7 +138,7 @@
                 removed.append(fn)
             elif flag1 != flag2:
                 modified.append(fn)
-            elif node2 != _newnode:
+            elif node2 != newnodeid:
                 # When comparing files between two commits, we save time by
                 # not comparing the file contents when the nodeids differ.
                 # Note that this means we incorrectly report a reverted change
@@ -1587,7 +1583,7 @@
         """
         mf = self._repo['.']._manifestmatches(match, s)
         for f in s.modified + s.added:
-            mf[f] = _newnode
+            mf[f] = newnodeid
             mf.setflag(f, self.flags(f))
         for f in s.removed:
             if f in mf:
--- a/mercurial/copies.py	Mon Nov 07 18:57:54 2016 -0800
+++ b/mercurial/copies.py	Thu Nov 10 02:17:22 2016 -0800
@@ -278,7 +278,7 @@
         ac = repo.changelog.ancestors(revs, inclusive=True)
         ctx._ancestrycontext = ac
     def makectx(f, n):
-        if len(n) != 20:  # in a working context?
+        if len(n) != 20 or n in node.wdirnodes:  # in a working context?
             if ctx.rev() is None:
                 return ctx.filectx(f)
             return repo[None][f]
--- a/mercurial/node.py	Mon Nov 07 18:57:54 2016 -0800
+++ b/mercurial/node.py	Thu Nov 10 02:17:22 2016 -0800
@@ -17,6 +17,12 @@
 nullid = b"\0" * 20
 nullhex = hex(nullid)
 
+# Phony node value to stand-in for new files in some uses of
+# manifests.
+newnodeid = '!' * 20
+
+wdirnodes = set((newnodeid,))
+
 # pseudo identifiers for working directory
 # (they are experimental, so don't add too many dependencies on them)
 wdirrev = 0x7fffffff