changeset 50026:3550e4a88ccd

dirstate: add a context for tracking files change

Let us start to use it. We will enforce it later.

--- a/mercurial/dirstate.py	Mon Feb 13 21:51:45 2023 +0100
+++ b/mercurial/dirstate.py	Thu Jan 26 17:44:27 2023 +0100
@@ -92,6 +92,7 @@
 
 
 CHANGE_TYPE_PARENTS = "parents"
+CHANGE_TYPE_FILES = "files"
 
 
 @interfaceutil.implementer(intdirstate.idirstate)
@@ -215,6 +216,11 @@
         with self._changing(repo, CHANGE_TYPE_PARENTS) as c:
             yield c
 
+    @contextlib.contextmanager
+    def changing_files(self, repo):
+        with self._changing(repo, CHANGE_TYPE_FILES) as c:
+            yield c
+
     # here to help migration to the new code
     def parentchange(self):
         msg = (
@@ -250,6 +256,15 @@
             return False
         return self._change_type == CHANGE_TYPE_PARENTS
 
+    @property
+    def is_changing_files(self):
+        """Returns true if the dirstate is in the middle of a set of changes
+        that modify the files tracked or their sources.
+        """
+        if self._changing_level <= 0:
+            return False
+        return self._change_type == CHANGE_TYPE_FILES
+
     @propertycache
     def _map(self):
         """Return the dirstate contents (see documentation for dirstatemap)."""

--- a/mercurial/interfaces/dirstate.py	Mon Feb 13 21:51:45 2023 +0100
+++ b/mercurial/interfaces/dirstate.py	Thu Jan 26 17:44:27 2023 +0100
@@ -30,6 +30,9 @@
     is_changing_parents = interfaceutil.Attribute(
         """True if parents changes in progress."""
     )
+    is_changing_files = interfaceutil.Attribute(
+        """True if file tracking changes in progress."""
+    )
 
     def _ignorefiles():
         """Return a list of files containing patterns to ignore."""
@@ -49,6 +52,15 @@
         released.
         """
 
+    @contextlib.contextmanager
+    def changing_files(repo):
+        """Context manager for handling dirstate files.
+
+        If an exception occurs in the scope of the context manager,
+        the incoherent dirstate won't be written when wlock is
+        released.
+        """
+
     def hasdir(d):
         pass