[PATCH 4 of 4] verify: also check full manifest validity during verify runs

[Pierre-Yves David]

On 4/17/19 3:49 PM, Martin von Zweigbergk wrote:
> 
> 
> On Wed, Apr 17, 2019, 06:47 Pierre-Yves David 
> <pierre-yves.david at ens-lyon.org <mailto:pierre-yves.david at ens-lyon.org>> 
> wrote:
> 
> 
> 
>     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>
>     <mailto: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>>
>      >     <mailto: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>>
>      >      >     <mailto: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.
> 
> 
> Ah, no, it won't read sub manifests. You're simply skipping sub 
> manifests by including the "not dir" check.

so should we just drop the "not dir" ?

-- 
Pierre-Yves David