[PATCH 4 of 4] verify: also check full manifest validity during verify runs
Pierre-Yves David
pierre-yves.david at ens-lyon.org
Wed Apr 17 09:47:09 EDT 2019
On 4/17/19 3:06 PM, Martin von Zweigbergk wrote:
>
>
> On Wed, Apr 17, 2019, 03:34 Pierre-Yves David
> <pierre-yves.david at ens-lyon.org <mailto:pierre-yves.david at ens-lyon.org>>
> wrote:
>
> On 4/17/19 4:59 AM, Martin von Zweigbergk wrote:
> >
> >
> > On Tue, Apr 16, 2019, 16:46 Pierre-Yves David
> > <pierre-yves.david at ens-lyon.org
> <mailto:pierre-yves.david at ens-lyon.org>
> <mailto:pierre-yves.david at ens-lyon.org
> <mailto:pierre-yves.david at ens-lyon.org>>>
> > wrote:
> >
> > # HG changeset patch
> > # User Pierre-Yves David <pierre-yves.david at octobus.net
> <mailto:pierre-yves.david at octobus.net>
> > <mailto:pierre-yves.david at octobus.net
> <mailto:pierre-yves.david at octobus.net>>>
> > # Date 1551881213 -3600
> > # Wed Mar 06 15:06:53 2019 +0100
> > # Node ID ed796867a06764cd78a57b2ed0249353f5809319
> > # Parent 9bec7491e9b4cabdfa4d264e5213b1f416ec2607
> > # EXP-Topic verify
> > # Available At https://bitbucket.org/octobus/mercurial-devel/
> > # hg pull
> > https://bitbucket.org/octobus/mercurial-devel/ -r ed796867a067
> > verify: also check full manifest validity during verify runs
> >
> > Before this changes, `hg verify` only checked if a manifest
> revision
> > existed and
> > referenced the proper files. However it never checked the
> manifest
> > revision
> > content itself.
> >
> > Mercurial is expecting manifest entries to be sorted and will
> crash
> > otherwise.
> > Since `hg verify` did not attempted a full restoration of
> manifest
> > entry, it
> > could ignore this kind of corruption.
> >
> > This new check significantly increases the cost of a `hg verify`
> > run. This
> > especially affects large repository not using
> `sparse-revlog`. For
> > now, this is
> > hidden behind the `--full` experimental flag.
> >
> > diff --git a/mercurial/verify.py b/mercurial/verify.py
> > --- a/mercurial/verify.py
> > +++ b/mercurial/verify.py
> > @@ -337,6 +337,16 @@ class verifier(object):
> > filenodes.setdefault(fullpath,
> > {}).setdefault(fn, lr)
> > except Exception as inst:
> > self._exc(lr, _("reading delta %s") % short(n),
> > inst, label)
> > + if not dir and self._level >= VERIFY_FULL:
> >
> >
> > What does the "not dir" mean? I guess it's to do this check only
> for the
> > root directory when using tree manifests. Should we do it for all
> > directories?
>
> That is used earlier in the same function to denote "the root
> manifest".
> I think check the root manifest will trigger checks of the sub manifest
> but I am not sure, I am not too familiar tree manifest.
>
>
> I'm pretty sure it's about tree manifests. I asked just to make sure
> since it surprised me that you used that as part of the condition here.
I know it is about tree manifest, I am reusing a pattern used by earlier
code.
> Can we double
> check/fix this as a follow up ?
>
>
> It should be easy to check (just add a print statement and run tests,
> for example), so I don't see much reason to fix such a simple thing in a
> follow-up.
The question here is "Does reading the top level manifest will validated
the content of the sub manifest too". I don't know how reliably to check
it in a reasonable amount of time. I am not exposed to any tree manifest
user myself.
> Btw, it would be nice to have tests too, but I understand that that's
> harder to do. Thoughts on how it could be done? Prepared bundle or some
> python code for writing out a bad manifest entry should work, I guess.
The corruption I encounter requires to write buggy manifest by hand. I
agree if would be nice to cover that in the test. However, that requires
significantly more time and exceed my initial "let's just share that
code upstream" intend.
Cheers,
--
Pierre-Yves David
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