merge: fix race that could cause wrong size in dirstate The problem is that hg merge/update/etc work the following way: 1. figure out what files to update 2. apply the update to disk 3. apply the update to in-memory dirstate 4. write dirstate where step3 looks at the filesystem and assumes it sees the result of step2. If a file is changed between step2 and step3, step3 will record incorrect information in the dirstate. I avoid this by passing the size step3 needs directly from step2, for the common path (not implemented for change/delete conflicts for instance). I didn't fix the same race for the exec bit for now, because it's less likely to be problematic and I had trouble due to the fact that the dirstate stores the permissions differently from the manifest (st_mode vs '' 'l' 'x'), in combination with tests that pretend that symlinks are not supported. However, I moved the lstat from step3 to step2, which should tighten the race window markedly, both for the exec bit and for the mtime. Differential Revision: https://phab.mercurial-scm.org/D6475

--- a/hgext/sparse.py	Wed Jun 12 13:10:52 2019 -0400
+++ b/hgext/sparse.py	Mon May 27 16:55:46 2019 -0400
@@ -228,7 +228,7 @@
     hint = _('include file with `hg debugsparse --include <pattern>` or use ' +
              '`hg add -s <file>` to include file directory while adding')
     for func in editfuncs:
-        def _wrapper(orig, self, *args):
+        def _wrapper(orig, self, *args, **kwargs):
             sparsematch = self._sparsematcher
             if not sparsematch.always():
                 for f in args:
@@ -237,7 +237,7 @@
                         raise error.Abort(_("cannot add '%s' - it is outside "
                                             "the sparse checkout") % f,
                                           hint=hint)
-            return orig(self, *args)
+            return orig(self, *args, **kwargs)
         extensions.wrapfunction(dirstate.dirstate, func, _wrapper)
 
 @command('debugsparse', [