diff mercurial/lock.py @ 43778:888bd39ed555

lock: pass "success" boolean to _afterlock callbacks

This lets the callback decide if it should actually run or not. I suspect that
most callbacks (and hooks) *should not* run in this scenario, but I'm trying
to not break any existing behavior. `persistmanifestcache`, however, seems
actively dangerous to run: we just encountered an exception and the repo is in
an unknown state (hopefully a consistent one due to transactions, but this is
not 100% guaranteed), and the data we cache may be based on this unknown
state.

This was observed by our users since we wrap some of the functions that
persistmanifestcache calls and it expects that the repo object is in a certain
state that we'd set up earlier. If the user hits ctrl-c before we establish
that state, we end up crashing there. I'm going to  make that extension
resilient to this issue, but figured it might be a common issue and should be
handled here as well instead of just working around the issue.

Differential Revision: https://phab.mercurial-scm.org/D7459

--- a/mercurial/lock.py	Fri Nov 22 11:08:59 2019 -0800
+++ b/mercurial/lock.py	Tue Nov 19 18:38:17 2019 -0800
@@ -233,7 +233,8 @@
         return self
 
     def __exit__(self, exc_type, exc_value, exc_tb):
-        self.release()
+        success = all(a is None for a in (exc_type, exc_value, exc_tb))
+        self.release(success=success)
 
     def __del__(self):
         if self.held:
@@ -408,7 +409,7 @@
                 self.acquirefn()
             self._inherited = False
 
-    def release(self):
+    def release(self, success=True):
         """release the lock and execute callback function if any
 
         If the lock has been acquired multiple times, the actual release is
@@ -433,7 +434,7 @@
             # at all.
             if not self._parentheld:
                 for callback in self.postrelease:
-                    callback()
+                    callback(success)
                 # Prevent double usage and help clear cycles.
                 self.postrelease = None