Try to detect #207 as early as possible.

cinnabar/githg.py

@@ -31,6 +31,7 @@
 except ImportError:
     from urllib.parse import urlparse
 from .exceptions import (
+    Abort,
     AmbiguousGraftAbort,
     NothingToGraftException,
     OldUpgradeAbort,
@@ -1306,3 +1307,33 @@ def tagset_lines(tags):
                 interval_expired('fsck', 86400 * 7):
             logging.warn('Have you run `git cinnabar fsck` recently?')
         GitHgHelper.close(rollback=False)
+
+        # Try to detect issue #207 as early as possible.
+        GitHgHelper._helper = False
+        busted = False
+        from .hg.repo import getbundle_params, stored_files
+        for (node, (parent1, parent2)) in progress_iter(
+                "Checking {} imported file root and head revisions",
+                util.iteritems(stored_files)):
+            if not GitHgHelper.check_file(node, parent1, parent2):
+                busted = True
+                logging.error("Error in file %s" % node)
+        if busted:
+            import json
+            extra = ""
+            if getbundle_params:
+                extra = \
+                    "If it failed, please also copy/paste the following:\n"
+                extra += json.dumps(getbundle_params, sort_keys=True, indent=4)
+            raise Abort(
+                "It seems you have hit a known, rare, and difficult to "
+                "reproduce issue.\n"
+                "Your help would be appreciated.\n"
+                "Please try either `git cinnabar rollback` followed by the "
+                "same command that just\n"
+                "failed, or `git cinnabar reclone`.\n"
+                "Please open a new issue "
+                "(https://github.com/glandium/git-cinnabar/issues/new)\n"
+                "mentioning issue #207 and reporting whether the second "
+                "attempt succeeded.\n" + extra
+            )

cinnabar/hg/repo.py

@@ -63,6 +63,7 @@
 from collections import (
     defaultdict,
     deque,
+    OrderedDict,
 )
 from .bundle import (
     create_bundle,
@@ -425,6 +426,9 @@ def log_dag(tag):
     return [store.hg_changeset(h) for h in dag.heads('known')]
 
 
+getbundle_params = {}
+
+
 class HelperRepo(object):
     __slots__ = "_url", "_branchmap", "_heads", "_bookmarks", "_ui", "remote"
 
@@ -503,9 +507,13 @@ def known(self, nodes):
         return [b == b'1'[0] for b in result]
 
     def getbundle(self, name, heads, common, *args, **kwargs):
-        data = HgRepoHelper.getbundle((hexlify(h) for h in heads),
-                                      (hexlify(c) for c in common),
-                                      b','.join(kwargs.get('bundlecaps', ())))
+        heads = [hexlify(h) for h in heads]
+        common = [hexlify(c) for c in common]
+        bundlecaps = b','.join(kwargs.get('bundlecaps', ()))
+        getbundle_params["heads"] = heads
+        getbundle_params["common"] = common
+        getbundle_params["bundlecaps"] = bundlecaps
+        data = HgRepoHelper.getbundle(heads, common, bundlecaps)
         header = readexactly(data, 4)
         if header == b'HG20':
             return unbundle20(self.ui, data)
@@ -811,6 +819,9 @@ def iter_files(iter):
             assert False
 
 
+stored_files = OrderedDict()
+
+
 class BundleApplier(object):
     def __init__(self, bundle):
         self._bundle = store_changegroup(bundle)
@@ -824,13 +835,32 @@ def __call__(self, store):
                 next(self._bundle, None)):
             pass
 
-        def enumerate_files(iter):
+        def enumerate_files(iterator):
+            null_parents = (NULL_NODE_ID, NULL_NODE_ID)
             last_name = None
             count_names = 0
-            for count_chunks, (name, chunk) in enumerate(iter, start=1):
+            for count_chunks, (name, chunk) in enumerate(iterator, start=1):
                 if name != last_name:
                     count_names += 1
                 last_name = name
+                parents = (chunk.parent1, chunk.parent2)
+                # Try to detect issue #207 as early as possible.
+                # Keep track of file roots of files with metadata and at least
+                # one head that can be traced back to each of those roots.
+                # Or, in the case of updates, all heads.
+                if store._has_metadata or chunk.parent1 in stored_files or \
+                        chunk.parent2 in stored_files:
+                    stored_files[chunk.node] = parents
+                    for p in parents:
+                        if p == NULL_NODE_ID:
+                            continue
+                        if stored_files.get(p, null_parents) != null_parents:
+                            del stored_files[p]
+                elif parents == null_parents:
+                    diff = next(iter(chunk.patch), None)
+                    if diff and diff.start == 0 and \
+                            diff.text_data[:2] == b'\1\n':
+                        stored_files[chunk.node] = parents
                 yield (count_chunks, count_names), chunk
 
         for rev_chunk in progress_enum(