deltas: skip if projected delta size does not match text size constraint Before computing any delta, we get a basic estimation of the delta size we can expect and the resulted compressed value. We then checks this projected size against the ½ⁿ size constraints. This allows to exclude potential base candidates before doing any expensive computation. This only apply to the intermediate-snapshot case since this constraint only apply to them. In practice we only perform this new checks for the manifestlog. Manifest log combine two property: it is likely to have delta chain issue and its diffing/compression is fairly predictable. The initial author of this changeset is Valentin Gatien-Baron providing the initial idea and initial testing, Pierre-Yves David later consolidated the code in the right location and run more extensive testing.

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Our full contribution guidelines are in our wiki, please see:

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https://www.mercurial-scm.org/wiki/ContributingChanges

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If you just want a checklist to follow, you can go straight to

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https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist

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