perf: call _generatechangelog() instead of group() Now that we have a separate function for generating just the changelog bits, the perf command should call it so it gets more accurate behavior. This changes the results of this command on my hg repo significantly: ! wall 1.390502 comb 1.390000 user 1.370000 sys 0.020000 (best of 8) ! wall 1.768750 comb 1.760000 user 1.760000 sys 0.000000 (best of 6) Profiling seems to reveal that ~20% of execution time is spent in progress bar accounting and printing! If we run with progress.disable=true: ! wall 1.639134 comb 1.650000 user 1.630000 sys 0.020000 (best of 7) A nice speedup. But profiling still shows a good chunk of time being spent in progress bar accounting code. The reason is that the progress bar is conditionally enabled via an argument to cgpacker.group(). The previous code in perf.py calling into group() did not enable the progress bar but _generatechangelog() always does. I think it is important for the perf* commands to capture real-world use cases. And this code always runs with an active progress bar. So the regression is acceptable. That being said, terminal printing performance can vary substantially. I don't think perf* commands should test terminal printing unless explicitly desired. So I've disabled progress bar printing in this command. Differential Revision: https://phab.mercurial-scm.org/D4134

changegroup: factor changelog chunk generation into own function We have separate functions for generating manifests and filelogs. Let's split changelog into its own function so things are consistent. As part of this, we refactor the code slightly. Before, the changelog linknode callback was updating state on variables inherited via a closure. Since the closure is now separate from generate(), we need to a way pass state between generate() and _generatechangelog(). The return value of _generatechangelog() is a 2-tuple where the first item is a dict containing accumulated state. We then alias some of its members into the scope of generate() to reduce code churn. I will be converting other functions to a similar pattern in future commits. Differential Revision: https://phab.mercurial-scm.org/D4133

changegroup: pass function to resolve delta parents into constructor Previously, _deltaparent() encapsulated the logic for all 3 delta parent modes of operation. The choice of delta parent is static for the lifetime of the packer and can be passed into the packer as a callable. So do that. Differential Revision: https://phab.mercurial-scm.org/D4132

changegroup: restore original behavior of _nextclrevtolocalrev 0548f696795b accidentally changed the behavior of cgpacker._close(). The old behavior moved _nextclrevtolocalrev to _clrevtolocalrev only when _nextclrevtolocalrev was present and then removed _nextclrevtolocalrev. The bad behavior performed this move then cleared _clrevtolocalrev because it was the same object as _nextclrevtolocalrev. This commit restores the previous behavior. Surprisingly, no tests changed as a result of this bad logic. I'm not sure why. Differential Revision: https://phab.mercurial-scm.org/D4155

py3: whitelist another test caught by the ratchet Differential Revision: https://phab.mercurial-scm.org/D4173

debugcommands: force import of fileset in debugfileset It looks like Python 3's lazy importer is better than Python 2's for this command, and as a result we had no symbols in the filesetlang symbol table, which resulted in some really mysterious test-fileset.t failures around withstatus optimizations. Inserting this explicit import and forcing its evaluation fixes the test failure. Differential Revision: https://phab.mercurial-scm.org/D4172

linelog: optimize replacelines The optimization to avoid calling `annotate` inside `replacelines` is significant for practical use patterns. Before this patch: hg perflinelogedits ! wall 6.778478 comb 6.710000 user 6.700000 sys 0.010000 (best of 3) After this patch: hg perflinelogedits ! wall 0.136573 comb 0.140000 user 0.130000 sys 0.010000 (best of 63) Differential Revision: https://phab.mercurial-scm.org/D4150

linelog: extract `len(self._program)` to a local function This is a micro optimization prepared for following changes where `len(self._program)` is used in a loop. Differential Revision: https://phab.mercurial-scm.org/D4149

perf: add a command to benchmark linelog edits The use pattern of creating a linelog is usually by calling "replacelines" multiple times. Add a command to benchmark it. Differential Revision: https://phab.mercurial-scm.org/D4148

linelog: update internal help text This clarifies the details asked by @martinvonz on D3990. Differential Revision: https://phab.mercurial-scm.org/D4147