--- a/mercurial/cext/parsers.c	Tue Oct 19 10:52:13 2021 +0100
+++ b/mercurial/cext/parsers.c	Fri Oct 15 16:12:00 2021 +0200
@@ -139,18 +139,16 @@
 
 static inline bool dirstate_item_c_any_tracked(dirstateItemObject *self)
 {
-	const unsigned char mask = dirstate_flag_wc_tracked |
-	                           dirstate_flag_p1_tracked |
-	                           dirstate_flag_p2_info;
+	const int mask = dirstate_flag_wc_tracked | dirstate_flag_p1_tracked |
+	                 dirstate_flag_p2_info;
 	return (self->flags & mask);
 }
 
 static inline bool dirstate_item_c_added(dirstateItemObject *self)
 {
-	const unsigned char mask =
-	    (dirstate_flag_wc_tracked | dirstate_flag_p1_tracked |
-	     dirstate_flag_p2_info);
-	const unsigned char target = dirstate_flag_wc_tracked;
+	const int mask = (dirstate_flag_wc_tracked | dirstate_flag_p1_tracked |
+	                  dirstate_flag_p2_info);
+	const int target = dirstate_flag_wc_tracked;
 	return (self->flags & mask) == target;
 }
 
@@ -237,7 +235,7 @@
 
 static PyObject *dirstate_item_v2_data(dirstateItemObject *self)
 {
-	unsigned char flags = self->flags;
+	int flags = self->flags;
 	int mode = dirstate_item_c_v1_mode(self);
 	if ((mode & S_IXUSR) != 0) {
 		flags |= dirstate_flag_mode_exec_perm;
@@ -249,7 +247,7 @@
 	} else {
 		flags &= ~dirstate_flag_mode_is_symlink;
 	}
-	return Py_BuildValue("Bii", flags, self->size, self->mtime);
+	return Py_BuildValue("iii", flags, self->size, self->mtime);
 };
 
 static PyObject *dirstate_item_v1_state(dirstateItemObject *self)
@@ -372,9 +370,14 @@
 	if (!t) {
 		return NULL;
 	}
-	if (!PyArg_ParseTuple(args, "bii", &t->flags, &t->size, &t->mtime)) {
+	if (!PyArg_ParseTuple(args, "iii", &t->flags, &t->size, &t->mtime)) {
 		return NULL;
 	}
+	if (t->flags & dirstate_flag_expected_state_is_modified) {
+		t->flags &= ~(dirstate_flag_expected_state_is_modified |
+		              dirstate_flag_has_meaningful_data |
+		              dirstate_flag_has_file_mtime);
+	}
 	t->mode = 0;
 	if (t->flags & dirstate_flag_has_meaningful_data) {
 		if (t->flags & dirstate_flag_mode_exec_perm) {

--- a/mercurial/cext/util.h	Tue Oct 19 10:52:13 2021 +0100
+++ b/mercurial/cext/util.h	Fri Oct 15 16:12:00 2021 +0200
@@ -24,21 +24,22 @@
 /* clang-format off */
 typedef struct {
 	PyObject_HEAD
-	unsigned char flags;
+	int flags;
 	int mode;
 	int size;
 	int mtime;
 } dirstateItemObject;
 /* clang-format on */
 
-static const unsigned char dirstate_flag_wc_tracked = 1;
-static const unsigned char dirstate_flag_p1_tracked = 1 << 1;
-static const unsigned char dirstate_flag_p2_info = 1 << 2;
-static const unsigned char dirstate_flag_has_meaningful_data = 1 << 3;
-static const unsigned char dirstate_flag_has_file_mtime = 1 << 4;
-static const unsigned char dirstate_flag_has_directory_mtime = 1 << 5;
-static const unsigned char dirstate_flag_mode_exec_perm = 1 << 6;
-static const unsigned char dirstate_flag_mode_is_symlink = 1 << 7;
+static const int dirstate_flag_wc_tracked = 1;
+static const int dirstate_flag_p1_tracked = 1 << 1;
+static const int dirstate_flag_p2_info = 1 << 2;
+static const int dirstate_flag_has_meaningful_data = 1 << 3;
+static const int dirstate_flag_has_file_mtime = 1 << 4;
+static const int dirstate_flag_has_directory_mtime = 1 << 5;
+static const int dirstate_flag_mode_exec_perm = 1 << 6;
+static const int dirstate_flag_mode_is_symlink = 1 << 7;
+static const int dirstate_flag_expected_state_is_modified = 1 << 8;
 
 extern PyTypeObject dirstateItemType;
 #define dirstate_tuple_check(op) (Py_TYPE(op) == &dirstateItemType)

--- a/mercurial/helptext/internals/dirstate-v2.txt	Tue Oct 19 10:52:13 2021 +0100
+++ b/mercurial/helptext/internals/dirstate-v2.txt	Fri Oct 15 16:12:00 2021 +0200
@@ -383,6 +383,7 @@
     HAS_DIRECTORY_MTIME = 1 << 5
     MODE_EXEC_PERM = 1 << 6
     MODE_IS_SYMLINK = 1 << 7
+    EXPECTED_STATE_IS_MODIFIED = 1 << 8
 
   The meaning of each bit is described below.
 
@@ -461,8 +462,7 @@
     Must be unset for untracked nodes.
     For files tracked anywhere, if this is set:
     - The `size` field is the expected file size,
-      in bytes truncated its lower to 31 bits,
-      for the file to be clean.
+      in bytes truncated its lower to 31 bits.
     - The expected execute permission for the file’s owner
       is given by `MODE_EXEC_PERM`
     - The expected file type is given by `MODE_IS_SIMLINK`:
@@ -474,8 +474,7 @@
     Must be unset for untracked nodes.
     If this and `HAS_DIRECTORY_MTIME` are both unset,
     the `mtime` field is unused (set to zero).
-    If this is set, `mtime` is the modification time
-    expected for the file to be considered clean.
+    If this is set, `mtime` is the expected modification time.
 
 `HAS_DIRECTORY_MTIME`
     Must be unset for file tracked anywhere.
@@ -514,3 +513,20 @@
     If `HAS_MODE_AND_SIZE` is set,
     this indicates whether the file is expected to be a symlink
     as opposed to a normal file.
+
+`EXPECTED_STATE_IS_MODIFIED`
+    Must be unset for untracked nodes.
+    For:
+    - a file tracked anywhere
+    - that has expected metadata (`HAS_MODE_AND_SIZE` and `HAS_FILE_MTIME`)
+    - if that metadata matches
+      metadata found in the working directory with `stat`
+    This bit indicates the status of the file.
+    If set, the status is modified. If unset, it is clean.
+
+    In cases where `hg status` needs to read the contents of a file
+    because metadata is ambiguous, this bit lets it record the result
+    if the result is modified so that a future run of `hg status`
+    does not need to do the same again.
+    It is valid to never set this bit,
+    and consider expected metadata ambiguous if it is set.

--- 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),
         )
 

--- a/rust/hg-core/src/dirstate_tree/on_disk.rs	Tue Oct 19 10:52:13 2021 +0100
+++ b/rust/hg-core/src/dirstate_tree/on_disk.rs	Fri Oct 15 16:12:00 2021 +0200
@@ -110,6 +110,7 @@
         const HAS_DIRECTORY_MTIME = 1 << 5;
         const MODE_EXEC_PERM = 1 << 6;
         const MODE_IS_SYMLINK = 1 << 7;
+        const EXPECTED_STATE_IS_MODIFIED = 1 << 8;
     }
 }
 
@@ -351,12 +352,16 @@
         let wdir_tracked = self.flags().contains(Flags::WDIR_TRACKED);
         let p1_tracked = self.flags().contains(Flags::P1_TRACKED);
         let p2_info = self.flags().contains(Flags::P2_INFO);
-        let mode_size = if self.flags().contains(Flags::HAS_MODE_AND_SIZE) {
+        let mode_size = if self.flags().contains(Flags::HAS_MODE_AND_SIZE)
+            && !self.flags().contains(Flags::EXPECTED_STATE_IS_MODIFIED)
+        {
             Some((self.synthesize_unix_mode(), self.size.into()))
         } else {
             None
         };
-        let mtime = if self.flags().contains(Flags::HAS_FILE_MTIME) {
+        let mtime = if self.flags().contains(Flags::HAS_FILE_MTIME)
+            && !self.flags().contains(Flags::EXPECTED_STATE_IS_MODIFIED)
+        {
             Some(self.mtime.truncated_seconds.into())
         } else {
             None