view CONTRIBUTING @ 51352:7083b33a2699

delta-find: explicitly deal with usage of the cached revision

We can remove this from the general logic path and directly deal with this
corner case early.

This result in a small change in test-generaldelta.t as it turns out that:

- at commit time we (sometimes) precompute a delta against p1 and pass it as the
  cached delta.
- since cached delta where going through the same filtering as everything, we
  could "optimize" the base if it applied to an empty delta, resulting in not
  using the pre-computed delta.

The simpler logic fix the second item, making the cached delta base always actually
tested when requested.

Note that the computation of a fast delta against p1 only is questionable, but
looking into that is out of scope for this series.

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