Adapt to changes in Mercurial 4.6

Starting with Mercurial 4.6 repo.lookup() no longer accepts raw hashes
for lookups.

README.md

@@ -27,9 +27,9 @@ first time.
 System Requirements
 -------------------
 
-This project depends on Python 2.7 and the Python mercurial package.
-If Python is not installed, install it before proceeding.  The
-mercurial package can be installed with `pip install mercurial`.
+This project depends on Python 2.7 and the Mercurial 4.6 package. If
+Python is not installed, install it before proceeding. The Mercurial
+package can be installed with `pip install mercurial`.
 
 If you're on Windows, run the following commands in git bash (Git for
 Windows).

hg-fast-export.py

@@ -4,6 +4,7 @@
 # License: MIT <http://www.opensource.org/licenses/mit-license.php>
 
 from mercurial import node
+from mercurial.scmutil import revsymbol
 from hg2git import setup_repo,fixup_user,get_branch,get_changeset
 from hg2git import load_cache,save_cache,get_git_sha1,set_default_branch,set_origin_name
 from optparse import OptionParser
@@ -78,7 +79,7 @@ def get_filechanges(repo,revision,parents,mleft):
   l,c,r=[],[],[]
   for p in parents:
     if p<0: continue
-    mright=repo.changectx(p).manifest()
+    mright=revsymbol(repo,str(p)).manifest()
     l,c,r=split_dict(mleft,mright,l,c,r)
   l.sort()
   c.sort()
@@ -210,7 +211,7 @@ def get_branchname(name):
   wr(desc)
   wr()
 
-  ctx=repo.changectx(str(revision))
+  ctx=revsymbol(repo,str(revision))
   man=ctx.manifest()
   added,changed,removed,type=[],[],[],''
 
@@ -225,7 +226,7 @@ def get_branchname(name):
       # later non-merge revision: feed in changed manifest
       # if we have exactly one parent, just take the changes from the
       # manifest without expensively comparing checksums
-      f=repo.status(repo.lookup(parents[0]),revnode)[:3]
+      f=repo.status(parents[0],revnode)[:3]
       added,changed,removed=f[1],f[0],f[2]
       type='simple delta'
     else: # a merge with two parents
@@ -262,7 +263,7 @@ def export_note(ui,repo,revision,count,authors,encoding,is_first):
   if is_first:
     wr('from refs/notes/hg^0')
   wr('N inline :%d' % (revision+1))
-  hg_hash=repo.changectx(str(revision)).hex()
+  hg_hash=revsymbol(repo,str(revision)).hex()
   wr('data %d' % (len(hg_hash)))
   wr_no_nl(hg_hash)
   wr()

hg2git.py

@@ -4,6 +4,9 @@
 # License: MIT <http://www.opensource.org/licenses/mit-license.php>
 
 from mercurial import hg,util,ui,templatefilters
+from mercurial import error as hgerror
+from mercurial.scmutil import revsymbol,binnode
+
 import re
 import os
 import sys
@@ -69,7 +72,15 @@ def get_branch(name):
   return name
 
 def get_changeset(ui,repo,revision,authors={},encoding=''):
-  node=repo.lookup(revision)
+  # Starting with Mercurial 4.6 lookup no longer accepts raw hashes
+  # for lookups. Work around it by changing our behaviour depending on
+  # how it fails
+  try:
+    node=repo.lookup(revision)
+  except hgerror.ProgrammingError:
+    node=binnode(revsymbol(repo,str(revision))) # We were given a numeric rev
+  except hgerror.RepoLookupError:
+    node=revision # We got a raw hash
   (manifest,user,(time,timezone),files,desc,extra)=repo.changelog.read(node)
   if encoding:
     user=user.decode(encoding).encode('utf8')