matchers: fix the bug in rust PatternMatcher that made it cut off early This brings the rust output in line with the Python output.

tests: add an end-to-end test to show a bug in `visit_children_set` Concretely, `rootfilesin` is completely broken with respect to `visit_children_set` optimization.

tests: add tests and document expectations from visit_children_set in rust The tests this patch are adding have the form of formal spec in invariants::visit_children_set::holds, and then a series of checks that all examples must satisfy this formal spec. I tried to make the spec consistent with how this function is used and how it was originally conceived. This is in conflict with how it's documented in Rust. Some of the implementations also fail to implement this spec, which leads to bugs, in particular when complicated patterns are used with `hg status`.

tests: add a test that demonstrates a bug in rhg status pattern handling The bug is in [visit_children_set], will be elaborated on in follow-up changes.

bundle-spec: properly parse boolean configuration as boolean Before this changesets "v2;revbranchcache=no" would actually request the addition for a revbranchcache part as the non-empty string `"0"` is `True`

bundle-spec: properly identify changegroup-less bundle It is possible to produce a bundle without changegroup. For example if we want to only send phases or obsolescence information. However that lead to crash for command that identifies bundle content. So we fix that. The test will come in the next changesets, when we fix another bug preventing to generate such bundle by hand.

perf: create the temporary target next to the source in stream-consume See inline comment for rational.

setup: display return code information about failed `hg` call This help to understand what is going wrong when things goes wrong.

bundlespec: rationalize the way we specify stream bundle version Instead of having weird dedicated option for each version (v2, v3, etc) we reuse the same "stream" parameters. This is consistent with the ability to request a stream clone using "none-v2;stream=v2". This changeset introduce no user visible change, this is pure internal cleaning.

bundle: do no check the changegroup version if no changegroup is included We don't need to check the compatibility of something we will not use. In practice this was getting in the was of `streamv2` bundles on a narrow repository as the 'cg.version=02' value was rejected by this checks.

perf-stream-consume: use the source repository config when applying This might contains critical configuration for the benchmark, like enabling of extensions like narrow.

unbundle: move most of the logic on cmdutil to help debug::unbundle reuse This make sure `hg debug::unbundle` focus on the core logic.

postincoming: move to cmdutil This looks like a good place for it to live.

postincoming: avoid computing branchhead if no report will be posted This otherwise defeat some of the branch v3 optimization.

streamclone: stop listing files for entries that have no volatile files This will save a lot of python related time. This significantly boost performance. The following number comes from a large private repository using perf::stream-locked-section: base-line: 35.04 seconds prev-change: 24.51 seconds (-30%) prev-change: 20.88 seconds (-40%) prev-change: 14.22 seconds (-60%) this-change: 11.58 seconds (-67% from baseline; -18% from prev)

stream-clone: disable gc for the initial section for the v3 format The number of small container created turn Python in a gc-frenzy that seriously impact performance. This significantly boost performance. The following number comes from a large private repository using perf::stream-locked-section: base-line: 35.04 seconds prev-change: 24.51 seconds (-30%) prev-change: 20.88 seconds (-40%) this-change: 14.22 seconds (-60% from baseline; -31% from prev)

stream-clone: disable gc for `_entries_walk` duration The number of small container created turn Python in a gc-frenzy that seriously impact performance. This significantly boost performance. The following number comes from a large private repository using perf::stream-locked-section: base-line: 35.04 seconds prev-change: 24.51 seconds (-30%) this-change: 20.88 seconds (-40% from baseline; -15% from previous changes)

nocg: make the utility work are both a decorator and context manager In some case, the context manager version will be simpler.

stream-clone: stop getting the file size of all file in v3 The point of v3 is to do less work in the locked section. It was currently not the case. This significantly boost performance. The following number comes from a large private repository using perf::stream-locked-section: base-line: 35.03 seconds this-change: 24.50 seconds (-30%)

stream: in v3, skip the "size" fast path if the entries as some unknown size We are about to prefetch size during the lock less in the v3 case. So we need to avoid trying to use that prefetched size when it is not available. See next changeset for the motivation.

perf-stream-locked-section: advertise the right version key in the help As the v3 format is still experimental, its key is "v3-exp". The help text was not pointing that out. (we also fix `perf::stream-generate` in the process)

perf-stream-locked-section: fix the call to the v3 generator That generator simply return chunks so we should not assign the return to a tuple.

perf-stream-locked-section: actually use v1 generation when requested We were fetching a v1 generator but actually using the v2 function…

branching: merge stable into default