# HG changeset patch
# User Kyle Lippincott <spectral@google.com>
# Date 2019-11-20 02:38:17
# Node ID 888bd39ed555884ef9ac5de6b9b7c3bc1a0ca29e
# Parent  c8e9a3636abe5bfbbfe1a0af2116f5f4c72550b0

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

diff --git a/hgext/remotefilelog/__init__.py b/hgext/remotefilelog/__init__.py
--- a/hgext/remotefilelog/__init__.py
+++ b/hgext/remotefilelog/__init__.py
@@ -1063,7 +1063,7 @@ def wcpprefetch(ui, repo, **kwargs):
     # update a revset with a date limit
     bgprefetchrevs = revdatelimit(ui, bgprefetchrevs)
 
-    def anon():
+    def anon(unused_success):
         if util.safehasattr(repo, b'ranprefetch') and repo.ranprefetch:
             return
         repo.ranprefetch = True
diff --git a/mercurial/bundle2.py b/mercurial/bundle2.py
--- a/mercurial/bundle2.py
+++ b/mercurial/bundle2.py
@@ -2372,7 +2372,7 @@ def handlebookmark(op, inpart):
 
         if pushkeycompat:
 
-            def runhook():
+            def runhook(unused_success):
                 for hookargs in allhooks:
                     op.repo.hook(b'pushkey', **pycompat.strkwargs(hookargs))
 
diff --git a/mercurial/changegroup.py b/mercurial/changegroup.py
--- a/mercurial/changegroup.py
+++ b/mercurial/changegroup.py
@@ -436,7 +436,7 @@ class cg1unpacker(object):
 
             if changesets > 0:
 
-                def runhooks():
+                def runhooks(unused_success):
                     # These hooks run when the lock releases, not when the
                     # transaction closes. So it's possible for the changelog
                     # to have changed since we last saw it.
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -2203,7 +2203,7 @@ class localrepository(object):
             # fixes the function accumulation.
             hookargs = tr2.hookargs
 
-            def hookfunc():
+            def hookfunc(unused_success):
                 repo = reporef()
                 if hook.hashook(repo.ui, b'txnclose-bookmark'):
                     bmchanges = sorted(tr.changes[b'bookmarks'].items())
@@ -2615,7 +2615,7 @@ class localrepository(object):
                 l.postrelease.append(callback)
                 break
         else:  # no lock have been found.
-            callback()
+            callback(True)
 
     def lock(self, wait=True):
         '''Lock the repository store (.hg/store) and return a weak reference
@@ -2953,7 +2953,7 @@ class localrepository(object):
                     )
                 raise
 
-        def commithook():
+        def commithook(unused_success):
             # hack for command that use a temporary commit (eg: histedit)
             # temporary commit got stripped before hook release
             if self.changelog.hasnode(ret):
@@ -3399,7 +3399,7 @@ class localrepository(object):
         self.ui.debug(b'pushing key for "%s:%s"\n' % (namespace, key))
         ret = pushkey.push(self, namespace, key, old, new)
 
-        def runhook():
+        def runhook(unused_success):
             self.hook(
                 b'pushkey',
                 namespace=namespace,
diff --git a/mercurial/lock.py b/mercurial/lock.py
--- a/mercurial/lock.py
+++ b/mercurial/lock.py
@@ -233,7 +233,8 @@ class lock(object):
         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 @@ class lock(object):
                 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 @@ class lock(object):
             # at all.
             if not self._parentheld:
                 for callback in self.postrelease:
-                    callback()
+                    callback(success)
                 # Prevent double usage and help clear cycles.
                 self.postrelease = None
 
diff --git a/mercurial/manifest.py b/mercurial/manifest.py
--- a/mercurial/manifest.py
+++ b/mercurial/manifest.py
@@ -1572,7 +1572,11 @@ class manifestrevlog(object):
         reporef = weakref.ref(repo)
         manifestrevlogref = weakref.ref(self)
 
-        def persistmanifestcache():
+        def persistmanifestcache(success):
+            # Repo is in an unknown state, do not persist.
+            if not success:
+                return
+
             repo = reporef()
             self = manifestrevlogref()
             if repo is None or self is None:
diff --git a/tests/test-lock.py b/tests/test-lock.py
--- a/tests/test-lock.py
+++ b/tests/test-lock.py
@@ -65,7 +65,7 @@ class teststate(object):
     def releasefn(self):
         self._releasecalled = True
 
-    def postreleasefn(self):
+    def postreleasefn(self, success):
         self._postreleasecalled = True
 
     def assertacquirecalled(self, called):