D4041: revisions: allow "x123" to refer to nodeid prefix "123"

[martinvonz (Martin von Zweigbergk)]

martinvonz created this revision.
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REVISION SUMMARY
  When resolving "123" to a revision, we try to interpret it as revnum
  before we try to interpret it as a nodeid hex prefix. This can lead to
  the shortest valid prefix being longer than necessary. This patch lets
  us write such nodeids in a shorter form by prefixing them with "x"
  instead of adding more hex digits until they're longer than the
  longest decimal revnum.
  
  On my hg repo with almost 69k revisions, turning this feature on saves
  on average 0.4% on the average nodeid length. That clearly doesn't
  justify this patch. However, it becomes more usefule when combined
  with the earlier patches in this series that let you disambiguate
  nodeid prefixes within a configured revset.
  
  Note that we attempt to resolve symbols as nodeid prefixes after we've
  exhausted all other posibilities, so this is a backwards compatible
  change (only queries that would previously fail may now succeed).
  
  I've still hidden this feature behind an experiemntal config option so
  we can roll it back if needed.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D4041

AFFECTED FILES
  mercurial/configitems.py
  mercurial/scmutil.py
  tests/test-revset.t

CHANGE DETAILS

diff --git a/tests/test-revset.t b/tests/test-revset.t
--- a/tests/test-revset.t
+++ b/tests/test-revset.t
@@ -1773,6 +1773,16 @@
 
 Test hexadecimal revision
   $ log 'id(2)'
+  $ log 'id(5)'
+  2
+  $ hg --config experimental.revisions.prefixhexnode=yes log --template '{rev}\n' -r 'id(x5)'
+  2
+  $ hg --config experimental.revisions.prefixhexnode=yes log --template '{rev}\n' -r 'x5'
+  2
+  $ hg --config experimental.revisions.prefixhexnode=yes log --template '{rev}\n' -r 'id(x)'
+  $ hg --config experimental.revisions.prefixhexnode=yes log --template '{rev}\n' -r 'x'
+  abort: 00changelog.i@: ambiguous identifier!
+  [255]
   $ log 'id(23268)'
   4
   $ log 'id(2785f51eece)'
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -437,6 +437,9 @@
     return '%d:%s' % (rev, hexfunc(node))
 
 def resolvehexnodeidprefix(repo, prefix):
+    if (prefix.startswith('x') and
+        repo.ui.configbool('experimental', 'revisions.prefixhexnode')):
+        prefix = prefix[1:]
     try:
         # Uses unfiltered repo because it's faster when prefix is ambiguous/
         # This matches the shortesthexnodeidprefix() function below.
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -584,6 +584,9 @@
 coreconfigitem('experimental', 'removeemptydirs',
     default=True,
 )
+coreconfigitem('experimental', 'revisions.prefixhexnode',
+    default=False,
+)
 coreconfigitem('experimental', 'revlogv2',
     default=None,
 )



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