diff --git a/mercurial/filelog.py b/mercurial/filelog.py
--- a/mercurial/filelog.py
+++ b/mercurial/filelog.py
@@ -189,6 +189,9 @@
 
         return True
 
+    def verifyintegrity(self, state):
+        return self._revlog.verifyintegrity(state)
+
     # TODO these aren't part of the interface and aren't internal methods.
     # Callers should be fixed to not use them.
 
diff --git a/mercurial/repository.py b/mercurial/repository.py
--- a/mercurial/repository.py
+++ b/mercurial/repository.py
@@ -318,6 +318,20 @@
             _('cannot %s; remote repository does not support the %r '
               'capability') % (purpose, name))
 
+class iverifyproblem(interfaceutil.Interface):
+    """Represents a problem with the integrity of the repository.
+
+    Instances of this interface are emitted to describe an integrity issue
+    with a repository (e.g. corrupt storage, missing data, etc).
+
+    Instances are essentially messages associated with severity.
+    """
+    warning = interfaceutil.Attribute(
+        """Message indicating a non-fatal problem.""")
+
+    error = interfaceutil.Attribute(
+        """Message indicating a fatal problem.""")
+
 class irevisiondelta(interfaceutil.Interface):
     """Represents a delta between one revision and another.
 
@@ -749,6 +763,17 @@
         TODO this is used by verify and it should not be part of the interface.
         """
 
+    def verifyintegrity(state):
+        """Verifies the integrity of file storage.
+
+        ``state`` is a dict holding state of the verifier process. It can be
+        used to communicate data between invocations of multiple storage
+        primitives.
+
+        The method yields objects conforming to the ``iverifyproblem``
+        interface.
+        """
+
 class idirs(interfaceutil.Interface):
     """Interface representing a collection of directories from paths.
 
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -254,6 +254,12 @@
     revision = attr.ib()
     delta = attr.ib()
 
+@interfaceutil.implementer(repository.iverifyproblem)
+@attr.s(frozen=True)
+class revlogproblem(object):
+    warning = attr.ib(default=None)
+    error = attr.ib(default=None)
+
 # index v0:
 #  4 bytes: offset
 #  4 bytes: compressed length
@@ -2581,3 +2587,23 @@
         if dataread is not idxread:
             dataread.close()
             datawrite.close()
+
+    def verifyintegrity(self, state):
+        """Verifies the integrity of the revlog.
+
+        Yields ``revlogproblem`` instances describing problems that are
+        found.
+        """
+        dd, di = self.checksize()
+        if dd:
+            yield revlogproblem(error=_('data length off by %d bytes') % dd)
+        if di:
+            yield revlogproblem(error=_('index contains %d extra bytes') % di)
+
+        if self.version != REVLOGV0:
+            if not state['revlogv1']:
+                yield revlogproblem(warning=_("warning: `%s' uses revlog "
+                                             "format 1") % self.indexfile)
+        elif state['revlogv1']:
+            yield revlogproblem(warning=_("warning: `%s' uses revlog "
+                                          "format 0") % self.indexfile)
diff --git a/mercurial/verify.py b/mercurial/verify.py
--- a/mercurial/verify.py
+++ b/mercurial/verify.py
@@ -341,6 +341,10 @@
             elif (size > 0 or not revlogv1) and f.startswith('data/'):
                 storefiles.add(_normpath(f))
 
+        state = {
+            'revlogv1': self.revlogv1,
+        }
+
         files = sorted(set(filenodes) | set(filelinkrevs))
         revisions = 0
         progress = ui.makeprogress(_('checking'), unit=_('files'),
@@ -373,7 +377,19 @@
                                   ff)
                         self.fncachewarned = True
 
-            self.checklog(fl, f, lr)
+            if not len(fl) and (self.havecl or self.havemf):
+                self.err(lr, _("empty or missing %s") % f)
+            else:
+                for problem in fl.verifyintegrity(state):
+                    if problem.warning:
+                        self.warn(problem.warning)
+                    elif problem.error:
+                        self.err(lr, problem.error, f)
+                    else:
+                        raise error.ProgrammingError(
+                            'problem instance does not set warning or error '
+                            'attribute: %s' % problem.msg)
+
             seen = {}
             rp = None
             for i in fl:
diff --git a/tests/test-check-interfaces.py b/tests/test-check-interfaces.py
--- a/tests/test-check-interfaces.py
+++ b/tests/test-check-interfaces.py
@@ -229,4 +229,8 @@
         basenode=b'')
     checkzobject(rdr)
 
+    ziverify.verifyClass(repository.iverifyproblem,
+                         revlog.revlogproblem)
+    checkzobject(revlog.revlogproblem())
+
 main()