[PATCH] wireproto: allow unbundle with hashed heads parameter (issue2126)

[Shuhei Takahashi]

# HG changeset patch
# User nya
# Date 1302882677 -32400
# Branch nya
# Node ID 8bd94325c6a8ce894a767d247f02d40a543d0977
# Parent  3d83c7d70a98a1fd4ff1ad4f840c8ce82100bfdb
wireproto: allow unbundle with hashed heads parameter (issue2126)

Current wire protocol of unbundle sends the list of all heads in the remote
repository to avoid race condition.  This causes "URL too long" error on HTTP
server when the repository has many heads.

This change allows clients to send SHA1 hash of heads parameter instead.
Also, this introduces "unbundlehash" capability to inform them that the server
accepts hashed heads parameter.

diff -r 3d83c7d70a98 -r 8bd94325c6a8 mercurial/wireproto.py
--- a/mercurial/wireproto.py	Wed Apr 13 13:06:35 2011 -0500
+++ b/mercurial/wireproto.py	Sat Apr 16 00:51:17 2011 +0900
@@ -139,7 +139,12 @@
         remote server as a bundle. Return an integer indicating the
         result of the push (see localrepository.addchangegroup()).'''
 
-        ret, output = self._callpush("unbundle", cg, heads=encodelist(heads))
+        if self.capable('unbundlehash'):
+            heads = encodelist(['hashed', util.sha1(''.join(heads)).digest()])
+        else:
+            heads = encodelist(heads)
+
+        ret, output = self._callpush("unbundle", cg, heads=heads)
         if ret == "":
             raise error.ResponseError(
                 _('push failed:'), output)
@@ -216,7 +221,8 @@
     return "".join(r)
 
 def capabilities(repo, proto):
-    caps = 'lookup changegroupsubset branchmap pushkey known getbundle'.split()
+    caps = ('lookup changegroupsubset branchmap pushkey known getbundle ' +
+            'unbundlehash').split()
     if _allowstream(repo.ui):
         requiredformats = repo.requirements & repo.supportedformats
         # if our local revlogs are just revlogv1, add 'stream' cap
@@ -353,7 +359,9 @@
 
     def check_heads():
         heads = repo.heads()
-        return their_heads == ['force'] or their_heads == heads
+        heads_hash = util.sha1(''.join(heads)).digest()
+        return (their_heads == ['force'] or their_heads == heads or
+                their_heads == ['hashed', heads_hash])
 
     proto.redirect()
 
diff -r 3d83c7d70a98 -r 8bd94325c6a8 tests/test-hgweb-commands.t
--- a/tests/test-hgweb-commands.t	Wed Apr 13 13:06:35 2011 -0500
+++ b/tests/test-hgweb-commands.t	Sat Apr 16 00:51:17 2011 +0900
@@ -943,7 +943,7 @@
   $ "$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT '?cmd=capabilities'; echo
   200 Script output follows
   
-  lookup changegroupsubset branchmap pushkey known getbundle unbundle=HG10GZ,HG10BZ,HG10UN
+  lookup changegroupsubset branchmap pushkey known getbundle unbundlehash unbundle=HG10GZ,HG10BZ,HG10UN
 
 heads
 
diff -r 3d83c7d70a98 -r 8bd94325c6a8 tests/test-unbundlehash.t
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-unbundlehash.t	Sat Apr 16 00:51:17 2011 +0900
@@ -0,0 +1,31 @@
+
+Test wire protocol unbundle with hashed heads (capability: unbundlehash)
+
+Create a remote repository.
+
+  $ hg init remote
+  $ hg serve -R remote --config web.push_ssl=False --config web.allow_push=* -p $HGPORT -d --pid-file=hg1.pid -E error.log -A access.log
+  $ cat hg1.pid >> $DAEMON_PIDS
+
+Clone the repository and push a change.
+
+  $ hg clone http://localhost:$HGPORT/ local
+  no changes found
+  updating to branch default
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ touch local/README
+  $ hg ci -R local -A -m hoge
+  adding README
+  $ hg push -R local
+  pushing to http://localhost:$HGPORT/
+  searching for changes
+  remote: adding changesets
+  remote: adding manifests
+  remote: adding file changes
+  remote: added 1 changesets with 1 changes to 1 files
+
+Ensure hashed heads format is used.
+The hash here is always the same since the remote repository only has the null head.
+
+  $ cat access.log | grep unbundle
+  * - - [*] "POST /?cmd=unbundle&heads=686173686564+6768033e216468247bd031a0a2d9876d79818f8f HTTP/1.1" 200 - (glob)