Adapt to changes in Mercurial 4.6

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

README.md

@@ -24,6 +24,16 @@ you want to report a security bug. That way the next person having the
 same problem can benefit from the time spent solving the problem the
 first time.
 
+System Requirements
+-------------------
+
+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).
+
 Usage
 -----
 
@@ -33,7 +43,8 @@ Using hg-fast-export is quite simple for a mercurial repository <repo>:
 mkdir repo-git # or whatever
 cd repo-git
 git init
-hg-fast-export.sh -r <repo>
+hg-fast-export.sh -r <local-repo>
+git checkout HEAD
 ```
 
 Please note that hg-fast-export does not automatically check out the

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()
@@ -153,9 +154,13 @@ def sanitize_name(name,what="branch", mapping={}):
   # modifying names which previously were not touched it will break
   # preexisting setups which are doing incremental imports.
   #
-  # Use the -B and -T options to mangle branch and tag names
-  # instead. If you have a source repository where this is too much
-  # work to do manually, write a tool that does it for you.
+  # Fast-export tries to not inflict arbitrary naming policy on the
+  # user, instead it aims to provide mechanisms allowing the user to
+  # apply their own policy. Therefore do not add a transform which can
+  # already be implemented with the -B and -T options to mangle branch
+  # and tag names. If you have a source repository where this is too
+  # much work to do manually, write a tool that does it for you.
+  #
 
   def dot(name):
     if not name: return name
@@ -206,7 +211,7 @@ def export_commit(ui,repo,revision,old_marks,max,count,authors,
   wr(desc)
   wr()
 
-  ctx=repo.changectx(str(revision))
+  ctx=revsymbol(repo,str(revision))
   man=ctx.manifest()
   added,changed,removed,type=[],[],[],''
 
@@ -221,7 +226,7 @@ def export_commit(ui,repo,revision,old_marks,max,count,authors,
       # 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
@@ -258,7 +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')