diff mercurial/revlogutils/constants.py @ 40047:8e398628a3f2

repository: define and use revision flag constants

Revlogs have a per-revision 2 byte field holding integer flags that
define how revision data should be interpreted. For historical reasons,
these integer values are sent verbatim on the wire protocol as part of
changegroup data.

From a semantic standpoint, the flags that go out over the wire are
different from the flags stored internally by revlogs. Failure to
establish this semantic distinction creates unwanted strong coupling
between revlog's internals and the wire protocol.

This commit establishes new constants on the repository module that
define the revision flags used by the wire protocol (and by some
internal storage APIs, sadly). The changegroups internals documentation
has been updated to document them explicitly. Various references
throughout the repo now use the repository constants instead of the
revlog constants. This is done to make it clear that we're operating
on generic revision data and this isn't tied to revlogs.

Differential Revision: https://phab.mercurial-scm.org/D4860

--- a/mercurial/revlogutils/constants.py	Thu Oct 04 01:22:25 2018 +0200
+++ b/mercurial/revlogutils/constants.py	Wed Oct 03 12:57:01 2018 -0700
@@ -10,6 +10,7 @@
 from __future__ import absolute_import
 
 from .. import (
+    repository,
     util,
 )
 
@@ -28,9 +29,16 @@
 REVLOGV2_FLAGS = REVLOGV1_FLAGS
 
 # revlog index flags
-REVIDX_ISCENSORED = (1 << 15) # revision has censor metadata, must be verified
-REVIDX_ELLIPSIS = (1 << 14) # revision hash does not match data (narrowhg)
-REVIDX_EXTSTORED = (1 << 13) # revision data is stored externally
+
+# For historical reasons, revlog's internal flags were exposed via the
+# wire protocol and are even exposed in parts of the storage APIs.
+
+# revision has censor metadata, must be verified
+REVIDX_ISCENSORED = repository.REVISION_FLAG_CENSORED
+# revision hash does not match data (narrowhg)
+REVIDX_ELLIPSIS = repository.REVISION_FLAG_ELLIPSIS
+# revision data is stored externally
+REVIDX_EXTSTORED = repository.REVISION_FLAG_EXTSTORED
 REVIDX_DEFAULT_FLAGS = 0
 # stable order in which flags need to be processed and their processors applied
 REVIDX_FLAGS_ORDER = [