D3370: scmutil: introduce shortesthexnodeidprefix()

[martinvonz (Martin von Zweigbergk)]

martinvonz created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  We have scmutil.resolvehexnodeidprefix() for resolving a prefix to a
  full nodeid, so it makes sense to have the inverse method next to
  it. For now it just delegates to changelog.shortest(), but it will
  soon also make sure it's called on the unfiltered repo, to match
  resolvehexnodeidprefix().
  
  Note that the change in show.py also makes it so the conversion from
  revnum to nodeid is done on the filtered repo, but that should be
  inconsequential since the revs are all from the filtered repo anyway.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3370

AFFECTED FILES
  hgext/show.py
  mercurial/scmutil.py
  mercurial/templatefuncs.py

CHANGE DETAILS

diff --git a/mercurial/templatefuncs.py b/mercurial/templatefuncs.py
--- a/mercurial/templatefuncs.py
+++ b/mercurial/templatefuncs.py
@@ -590,8 +590,8 @@
     # _partialmatch() of filtered changelog could take O(len(repo)) time,
     # which would be unacceptably slow. so we look for hash collision in
     # unfiltered space, which means some hashes may be slightly longer.
-    cl = context.resource(mapping, 'ctx')._repo.unfiltered().changelog
-    return cl.shortest(node, minlength)
+    repo = context.resource(mapping, 'ctx')._repo
+    return scmutil.shortesthexnodeidprefix(repo.unfiltered(), node, minlength)
 
 @templatefunc('strip(text[, chars])')
 def strip(context, mapping, args):
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -443,6 +443,10 @@
     repo.changelog.rev(node)  # make sure node isn't filtered
     return node
 
+def shortesthexnodeidprefix(repo, hexnode, minlength=1):
+    """Find the shortest unambiguous prefix that matches hexnode."""
+    return repo.changelog.shortest(hexnode)
+
 def isrevsymbol(repo, symbol):
     """Checks if a symbol exists in the repo.
 
diff --git a/hgext/show.py b/hgext/show.py
--- a/hgext/show.py
+++ b/hgext/show.py
@@ -45,6 +45,7 @@
     registrar,
     revset,
     revsetlang,
+    scmutil,
 )
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
@@ -447,8 +448,10 @@
     if not revs:
         return minlen
     # don't use filtered repo because it's slow. see templater.shortest().
-    cl = repo.unfiltered().changelog
-    return max(len(cl.shortest(hex(cl.node(r)), minlen)) for r in revs)
+    cl = repo.changelog
+    return max(len(scmutil.shortesthexnodeidprefix(repo.unfiltered(),
+                                                   hex(cl.node(r)),
+                                                   minlen)) for r in revs)
 
 # Adjust the docstring of the show command so it shows all registered views.
 # This is a bit hacky because it runs at the end of module load. When moved



To: martinvonz, #hg-reviewers
Cc: mercurial-devel