diff mercurial/pure/parsers.py @ 48250:1730b2fceaa1

dirstate-v2: adds a flag to mark a file as modified

Right now, a files with a file system state that requires a lookup (same size,
different mtime) will requires a lookup. If the result of that lookup is a
modified files, it will remains ambiguous, requiring a lookup on the next status
run too.

To fix this, we introduce a dedicated flag in the new format. Such flag will
allow to record such file as "known modified" avoiding an extra lookup later.

As None of the associate code currently exist in the status code, we do the
minimal implementation: if we read a dirstate entry with this flag set, we make
it as "ambiguous" so that the next status code has to look it up. The same as it
would have to without this flag existing anyway.

Differential Revision: https://phab.mercurial-scm.org/D11681

--- a/mercurial/pure/parsers.py	Tue Oct 19 10:52:13 2021 +0100
+++ b/mercurial/pure/parsers.py	Fri Oct 15 16:12:00 2021 +0200
@@ -53,6 +53,7 @@
 _DIRSTATE_V2_HAS_DIRCTORY_MTIME = 1 << 5  # Unused when Rust is not available
 DIRSTATE_V2_MODE_EXEC_PERM = 1 << 6
 DIRSTATE_V2_MODE_IS_SYMLINK = 1 << 7
+DIRSTATE_V2_EXPECTED_STATE_IS_MODIFIED = 1 << 8
 
 
 @attr.s(slots=True, init=False)
@@ -123,7 +124,15 @@
     def from_v2_data(cls, flags, size, mtime):
         """Build a new DirstateItem object from V2 data"""
         has_mode_size = bool(flags & DIRSTATE_V2_HAS_MODE_AND_SIZE)
+        has_meaningful_mtime = bool(flags & DIRSTATE_V2_HAS_FILE_MTIME)
         mode = None
+
+        if flags & +DIRSTATE_V2_EXPECTED_STATE_IS_MODIFIED:
+            # we do not have support for this flag in the code yet,
+            # force a lookup for this file.
+            has_mode_size = False
+            has_meaningful_mtime = False
+
         if has_mode_size:
             assert stat.S_IXUSR == 0o100
             if flags & DIRSTATE_V2_MODE_EXEC_PERM:
@@ -139,7 +148,7 @@
             p1_tracked=bool(flags & DIRSTATE_V2_P1_TRACKED),
             p2_info=bool(flags & DIRSTATE_V2_P2_INFO),
             has_meaningful_data=has_mode_size,
-            has_meaningful_mtime=bool(flags & DIRSTATE_V2_HAS_FILE_MTIME),
+            has_meaningful_mtime=has_meaningful_mtime,
             parentfiledata=(mode, size, mtime),
         )