merge: Use git_index__fill to populate the index
#3549
Conversation
Instead of calling `git_index_add` in a loop, use the new `git_index_fill` internal API to fill the index with the initial staged entries. The new `fill` helper assumes that all the entries will be unique and valid, so it can append them at the end of the entries vector and only sort it once at the end. It performs no validation checks. This prevents the quadratic behavior caused by having to sort the entries list once after every insertion.
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merge: Use `git_index__fill` to populate the index
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Damn, that was some quick code review hmmpf. |
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By hmmmpf I meant that I was not sure at all of the quality of this implementation (am I right on my assumptions about entries not colliding and being valid?). Guess it's time to blindly trust @ethomson again :D |
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This is in a new index, so we won't collide with any old entries. And the staged/successfully-merged entries would only have a single name, so I figured it was fine. |
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Ayup, I think I agree. I have however noticed that we're not adjusting the length mask on the flags of the index... It doesn't seem like the length mask is used anywhere, but we should probably adjust it nonetheless. And we should also perform filemode normalization, just in case the original filemode from the tree is not valid. |
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Nice catch. Seems like a classic "accidentally quadratic" case. If you were really worried about collisions, you should be able to do an |
See the commit message for details. This fixes a performance issue when merging truly large trees (roughly 1.5 million entries).
cc @carlosmn @ethomson (HAH how's that for a sabbatical)
cc @piki @simonsj