repozo: a truncated .deltafs results in a corrupted Data.fs on recovery, instead of an error

[Marius Gedminas]

You can truncate a *.deltafs in the middle, and repozo -R doesn't notice
-- it goes on to produce a corrupt Data.fs.

AFAIU the *.dat file contains enough information to do basic sanity
checking for the sizes of the various *.deltafs files. It'd be nice if
repozo -R noticed and aborted with a loud complaint when one of the
files is truncated. Checksum checking would be even nicer, but,
perhaps, expensive, and so maybe ought to require an extra command line
option to enable.

To reproduce:

  git clone git://github.com/mgedmin/repozo-testcases.git
  cd repozo-testcases
  make test2

[Marius Gedminas (mgedmin)]

I'm implementing a `repozo --verify` option to check *.fs/*.deltafs integrity against the *.dat file.

[Marius Gedminas (mgedmin)]

The feature is now implemented: https://github.com/zopefoundation/ZODB/pull/14

[Marius Gedminas (mgedmin)]

I would prefer repozo -R to do the checksum verification during recovery (unless you ask for --quick recovery).

But then I looked at the code and it seemed simpler to implement a standalone --verify, at least as a first step.