dirstate-item: make sure we load `mtime-second-ambiguous` from disk

Now that we support the associated logic, we can safely load it from it. It is
no longer necessary to ignore the stored mtime when the flag is encountered.

Differential Revision: https://phab.mercurial-scm.org/D11846

mercurial/cext/parsers.c

@@ -450,14 +450,6 b' static PyObject *dirstate_item_from_v2_m'
 		              dirstate_flag_has_meaningful_data |
 		              dirstate_flag_has_mtime);
 	}
-	if (t->flags & dirstate_flag_mtime_second_ambiguous) {
-		/* The current code is not able to do the more subtle comparison
-		 * that the MTIME_SECOND_AMBIGUOUS requires. So we ignore the
-		 * mtime */
-		t->flags &= ~(dirstate_flag_mtime_second_ambiguous |
-		              dirstate_flag_has_meaningful_data |
-		              dirstate_flag_has_mtime);
-	}
 	t->mode = 0;
 	if (t->flags & dirstate_flag_has_meaningful_data) {
 		if (t->flags & dirstate_flag_mode_exec_perm) {

mercurial/pure/parsers.py

@@ -149,10 +149,6 b' class DirstateItem(object):'
         """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_MTIME)
-        if flags & DIRSTATE_V2_MTIME_SECOND_AMBIGUOUS:
-            # The current code is not able to do the more subtle comparison that the
-            # MTIME_SECOND_AMBIGUOUS requires. So we ignore the mtime
-            has_meaningful_mtime = False
         mode = None
 
         if flags & +DIRSTATE_V2_EXPECTED_STATE_IS_MODIFIED:
@@ -179,13 +175,15 b' class DirstateItem(object):'
                 mode |= stat.S_IFLNK
             else:
                 mode |= stat.S_IFREG
+
+        second_ambiguous = flags & DIRSTATE_V2_MTIME_SECOND_AMBIGUOUS
         return cls(
             wc_tracked=bool(flags & DIRSTATE_V2_WDIR_TRACKED),
             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=has_meaningful_mtime,
-            parentfiledata=(mode, size, (mtime_s, mtime_ns, False)),
+            parentfiledata=(mode, size, (mtime_s, mtime_ns, second_ambiguous)),
             fallback_exec=fallback_exec,
             fallback_symlink=fallback_symlink,
         )

rust/hg-core/src/dirstate_tree/on_disk.rs

@@ -371,11 +371,12 b' impl Node {'
         let mtime = if self.flags().contains(Flags::HAS_MTIME)
             && !self.flags().contains(Flags::DIRECTORY)
             && !self.flags().contains(Flags::EXPECTED_STATE_IS_MODIFIED)
-            // The current code is not able to do the more subtle comparison that the
-            // MTIME_SECOND_AMBIGUOUS requires. So we ignore the mtime
-            && !self.flags().contains(Flags::MTIME_SECOND_AMBIGUOUS)
         {
-            Some(self.mtime.try_into()?)
+            let mut m: TruncatedTimestamp = self.mtime.try_into()?;
+            if self.flags().contains(Flags::MTIME_SECOND_AMBIGUOUS) {
+                m.second_ambiguous = true;
+            }
+            Some(m)
         } else {
             None
         };