[PATCH 4 of 4] devel: also warn about transaction started without a lock

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at fb.com>
# Date 1426046625 25200
#      Tue Mar 10 21:03:45 2015 -0700
# Node ID 5cab671ca5e7346e25b7d1a98cd9bdb1f4f25894
# Parent  fb5fc276e7112b1d2b849d42d3502103e95a6d6a
devel: also warn about transaction started without a lock

Nobody should even start a transaction on an unlocked repository. If developer
warning are enabled this will be reported. This use the same config as the bad
locking order as this is closely related.

diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -896,10 +896,18 @@ class localrepository(object):
         if tr and tr.running():
             return tr
         return None
 
     def transaction(self, desc, report=None):
+        if self.ui.develflag('check-locks'):
+            l = self._lockref and self._lockref()
+            if l is None or not l.held:
+                msg = 'transaction with no lock\n'
+                if self.ui.tracebackflag:
+                    util.debugstacktrace(msg, 2)
+                else:
+                    self.ui.write_err(msg)
         tr = self.currenttransaction()
         if tr is not None:
             return tr.nest()
 
         # abort here if the journal already exists
diff --git a/tests/test-devel-warnings.t b/tests/test-devel-warnings.t
--- a/tests/test-devel-warnings.t
+++ b/tests/test-devel-warnings.t
@@ -8,10 +8,11 @@
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > 
   > @command('buggylocking', [], '')
   > def buggylocking(ui, repo):
+  >     tr = repo.transaction('buggy')
   >     lo = repo.lock()
   >     wl = repo.wlock()
   > EOF
 
   $ cat << EOF >> $HGRCPATH
@@ -22,14 +23,16 @@
   > EOF
 
   $ hg init lock-checker
   $ cd lock-checker
   $ hg buggylocking
+  transaction with no lock
   "lock" taken before "wlock"
   $ cat << EOF >> $HGRCPATH
   > [devel]
   > all=0
   > check-locks=1
   > EOF
   $ hg buggylocking
+  transaction with no lock
   "lock" taken before "wlock"
   $ cd ..