exchange: ensure all outgoing subrepo references are present before pushing
authorMatt Harbison <matt_harbison@yahoo.com>
Thu, 12 Dec 2019 12:30:15 -0500
changeset 43913 4b7d5d10c45d
parent 43912 a89381e04c58
child 43914 69c4f3cf2cdf
exchange: ensure all outgoing subrepo references are present before pushing We've run into occasional problems with people committing a repo, and then amending or rebasing in the subrepo. That makes it so that the revision in the parent can't be checked out, and the problem gets propagated on push. Mercurial already tries to defend against this sort of dangling reference by pushing *all* subrepo revisions first. This reuses the checks that trigger warnings in `hg verify` to bail on the push unless using `--force`. I thought about putting this on the server side, but at that point, all of the data has been transferred, only to bail out. Additionally, SCM Manager hosts subrepos in a location that isn't nested in the parent, so normal subrepo code would complain that the subrepo is missing when run on the server. Because the push command pushes subrepos before calling this exchange code, a subrepo will be pushed before the parent is verified. Not great, but no dangling references are exchanged, so it solves the problem. This code isn't in the loop that pushes the subrepos because: 1) the list of outgoing revisions is needed to limit the scope of the check 2) the loop only accesses the current revision, and therefore can miss subrepos that were dropped in previous commits 3) this code is called when pushing a subrepo, so the protection is recursive I'm not sure if there's a cheap check for the list of files in the outgoing bundle. If there is, that would provide a fast path to bypass this check for people not using subrepos (or if no subrepo changes were made). There's probably also room for verifying other references like tags. But since that doesn't break checkouts, it's much less of a problem. Differential Revision: https://phab.mercurial-scm.org/D7616
mercurial/exchange.py
mercurial/subrepo.py
tests/test-amend-subrepo.t
--- a/mercurial/exchange.py	Thu Dec 05 16:19:16 2019 -0500
+++ b/mercurial/exchange.py	Thu Dec 12 12:30:15 2019 -0500
@@ -646,6 +646,8 @@
                 pushop.repo.checkpush(pushop)
                 _checkpublish(pushop)
                 _pushdiscovery(pushop)
+                if not pushop.force:
+                    _checksubrepostate(pushop)
                 if not _forcebundle1(pushop):
                     _pushbundle2(pushop)
                 _pushchangeset(pushop)
@@ -694,6 +696,17 @@
         step(pushop)
 
 
+def _checksubrepostate(pushop):
+    """Ensure all outgoing referenced subrepo revisions are present locally"""
+    for n in pushop.outgoing.missing:
+        ctx = pushop.repo[n]
+
+        if b'.hgsub' in ctx.manifest() and b'.hgsubstate' in ctx.files():
+            for subpath in sorted(ctx.substate):
+                sub = ctx.sub(subpath)
+                sub.verify(onpush=True)
+
+
 @pushdiscovery(b'changeset')
 def _pushdiscoverychangeset(pushop):
     """discover the changeset that need to be pushed"""
--- a/mercurial/subrepo.py	Thu Dec 05 16:19:16 2019 -0500
+++ b/mercurial/subrepo.py	Thu Dec 12 12:30:15 2019 -0500
@@ -429,10 +429,12 @@
         convert this repository from shared to normal storage.
         '''
 
-    def verify(self):
-        '''verify the integrity of the repository.  Return 0 on success or
-        warning, 1 on any error.
-        '''
+    def verify(self, onpush=False):
+        """verify the revision of this repository that is held in `_state` is
+        present and not hidden.  Return 0 on success or warning, 1 on any
+        error.  In the case of ``onpush``, warnings or errors will raise an
+        exception if the result of pushing would be a broken remote repository.
+        """
         return 0
 
     @propertycache
@@ -1013,26 +1015,35 @@
 
         hg.unshare(self.ui, self._repo)
 
-    def verify(self):
+    def verify(self, onpush=False):
         try:
             rev = self._state[1]
             ctx = self._repo.unfiltered()[rev]
             if ctx.hidden():
                 # Since hidden revisions aren't pushed/pulled, it seems worth an
                 # explicit warning.
-                ui = self._repo.ui
-                ui.warn(
-                    _(b"subrepo '%s' is hidden in revision %s\n")
-                    % (self._relpath, node.short(self._ctx.node()))
+                msg = _(b"subrepo '%s' is hidden in revision %s") % (
+                    self._relpath,
+                    node.short(self._ctx.node()),
                 )
+
+                if onpush:
+                    raise error.Abort(msg)
+                else:
+                    self._repo.ui.warn(b'%s\n' % msg)
             return 0
         except error.RepoLookupError:
             # A missing subrepo revision may be a case of needing to pull it, so
-            # don't treat this as an error.
-            self._repo.ui.warn(
-                _(b"subrepo '%s' not found in revision %s\n")
-                % (self._relpath, node.short(self._ctx.node()))
+            # don't treat this as an error for `hg verify`.
+            msg = _(b"subrepo '%s' not found in revision %s") % (
+                self._relpath,
+                node.short(self._ctx.node()),
             )
+
+            if onpush:
+                raise error.Abort(msg)
+            else:
+                self._repo.ui.warn(b'%s\n' % msg)
             return 0
 
     @propertycache
--- a/tests/test-amend-subrepo.t	Thu Dec 05 16:19:16 2019 -0500
+++ b/tests/test-amend-subrepo.t	Thu Dec 12 12:30:15 2019 -0500
@@ -164,4 +164,35 @@
   R .hgsub
   R .hgsubstate
 
+broken repositories will refuse to push
+
+#if obsstore-off
+  $ hg up -q -C 2
+#else
+  $ hg up -q -C 6
+#endif
+  $ echo c >> t/b
+  $ hg amend -q -R t
+
+  $ hg init ../dest
+  $ hg init ../dest/t
+  $ hg init ../dest/s
+  $ hg push -q ../dest
+  abort: subrepo 't' is hidden in revision 04aa62396ec6 (obsstore-on !)
+  abort: subrepo 't' not found in revision 04aa62396ec6 (obsstore-off !)
+  [255]
+
+... unless forced
+
+  $ hg push --force -q ../dest
+  $ hg verify -R ../dest
+  checking changesets
+  checking manifests
+  crosschecking files in changesets and manifests
+  checking files
+  checked 5 changesets with 12 changes to 4 files
+  checking subrepo links
+  subrepo 't' not found in revision 04aa62396ec6
+  subrepo 't' not found in revision 6bce99600681
+
   $ cd ..