D8414: nodemap: add a new mode option, with an optional "warn" value

[marmoute (Pierre-Yves David)]

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

REVISION SUMMARY
  When "warn" is set, user will get notified when the slow code, used for
  compatibility is used. This can help people to detect situation were using that
  feature will give them a slowdown instead of a speedup.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D8414

AFFECTED FILES
  mercurial/configitems.py
  mercurial/localrepo.py
  mercurial/revlogutils/nodemap.py
  tests/test-persistent-nodemap.t

CHANGE DETAILS

diff --git a/tests/test-persistent-nodemap.t b/tests/test-persistent-nodemap.t
--- a/tests/test-persistent-nodemap.t
+++ b/tests/test-persistent-nodemap.t
@@ -10,7 +10,9 @@
   > [devel]
   > persistent-nodemap=yes
   > EOF
-  $ hg debugbuilddag .+5000 --new-file
+  $ hg debugbuilddag .+5000 --new-file --config "experimental.exp-persistent-nodemap.mode=warn"
+  persistent nodemap in strict mode without efficient method (no-rust no-pure !)
+  persistent nodemap in strict mode without efficient method (no-rust no-pure !)
   $ hg debugnodemap --metadata
   uid: ???????????????? (glob)
   tip-rev: 5000
diff --git a/mercurial/revlogutils/nodemap.py b/mercurial/revlogutils/nodemap.py
--- a/mercurial/revlogutils/nodemap.py
+++ b/mercurial/revlogutils/nodemap.py
@@ -13,6 +13,8 @@
 import re
 import struct
 
+from ..i18n import _
+
 from .. import (
     error,
     node as nodemod,
@@ -105,6 +107,9 @@
     def addabort(self, *args, **kwargs):
         pass
 
+    def _report(self, *args):
+        pass
+
 
 def update_persistent_nodemap(revlog):
     """update the persistent nodemap right now
@@ -138,6 +143,11 @@
     ondisk_docket = revlog._nodemap_docket
     feed_data = util.safehasattr(revlog.index, "update_nodemap_data")
     use_mmap = revlog.opener.options.get(b"exp-persistent-nodemap.mmap")
+    mode = revlog.opener.options.get(b"exp-persistent-nodemap.mode")
+    if not can_incremental:
+        msg = _("persistent nodemap in strict mode without efficient method")
+        if mode == b'warn':
+            tr._report(b"%s\n" % msg)
 
     data = None
     # first attemp an incremental update of the data
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -937,6 +937,8 @@
         options[b'exp-persistent-nodemap'] = True
     if ui.configbool(b'experimental', b'exp-persistent-nodemap.mmap'):
         options[b'exp-persistent-nodemap.mmap'] = True
+    epnm = ui.config(b'experimental', b'exp-persistent-nodemap.mode')
+    options[b'exp-persistent-nodemap.mode'] = epnm
     if ui.configbool(b'devel', b'persistent-nodemap'):
         options[b'devel-force-nodemap'] = True
 
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -681,6 +681,9 @@
     b'experimental', b'exp-persistent-nodemap.mmap', default=True,
 )
 coreconfigitem(
+    b'experimental', b'exp-persistent-nodemap.mode', default=b'compat',
+)
+coreconfigitem(
     b'experimental', b'server.filesdata.recommended-batch-size', default=50000,
 )
 coreconfigitem(



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