parsers: simplify the code computing the phases We recently simplified the code computing the heads of a repo. This patch uses the same simplification for phase computation. We use index_get_parents instead of replicating its code.

parsers: move index_get_parents's declaration higher index_get_parents needs to be used in the phase computation code so we need to move its declaration higher to be able to call it. It cannot be moved any higher than that so we won't have any more patch doing the same thing.

record: add an operation arguments to customize recording ui This patch is part of a series of patches to change the recording ui to reflect the operation currently running (commit, shelve, revert ...). This patch adds a new argument to the recording function to reflect in the UI what operation we are running.

revset: reduce nesting of chained 'or' operations (issue4624) This reduces the stack depth of chained 'or' operations: - from O(n) to O(1) at the parsing, alias expansion and optimization phases - from O(n) to O(log(n)) at the evaluation phase simplifyinfixops() must be applied immediately after the parsing phase. Otherwise, alias expansion would crash by "maximum recursion depth exceeded" error. Test cases use 'x:y|y:z' instead of 'x|y' because I'm planning to optimize 'x|y' in a different way. Benchmarks: 0) 605b1d32c1c0 1) this patch revset #0: 0 + 1 + 2 + ... + 200 0) wall 0.026347 comb 0.030000 user 0.030000 sys 0.000000 (best of 101) 1) wall 0.023858 comb 0.030000 user 0.030000 sys 0.000000 (best of 112) revset #1: 0 + 1 + 2 + ... + 1000 0) maximum recursion depth exceeded 1) wall 0.483341 comb 0.480000 user 0.480000 sys 0.000000 (best of 20) revset #2: sort(0 + 1 + 2 + ... + 200) 0) wall 0.013404 comb 0.010000 user 0.010000 sys 0.000000 (best of 196) 1) wall 0.006814 comb 0.010000 user 0.010000 sys 0.000000 (best of 375) revset #3: sort(0 + 1 + 2 + ... + 1000) 0) maximum recursion depth exceeded 1) wall 0.035240 comb 0.040000 user 0.040000 sys 0.000000 (best of 100)

revset: add helper to build balanced addsets from chained 'or' operations This function will be used by revset.orset() and scmutil.revrange() to reduce the stack depth from O(n) to O(log(n)). We've bikeshed the interface of this function, but we couldn't come to an agreement. So we decided to attempt to make it move forward. marmoute: - new factory function isn't necessary for balanced addsets - addset.__init__ can just recurse, should handle "len(subsets) == 2+" yuja: - want to write all "len(subsets) == 0, 1, 2, 3+" cases in the same function - no recursion in __init__ for cosmetic reason: can't return, can't call __init__ directly I've changed it to a private function so that nobody would be tempted to utilize it.

revset: comment that we can't swap 'or' operands by weight Though the original code did nothing, it tried to optimize the calculation order by weight. But we can't simply swap 'ta' and 'tb' because it would change the order of revisions. For future reference, this patch keeps the modified version of the original code as comment.