diff mercurial/interfaces/dirstate.py @ 50026:3550e4a88ccd

dirstate: add a context for tracking files change

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

--- 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