phases: rework the logic of _pushdiscoveryphase to bound complexity This rework the various graph traversal in _pushdiscoveryphase to keep the complexity in check. This is done though a couple of things: - first, limiting the space we have to explore, for example, if we are not in publishing push, we don't need to consider remote draft roots that are also draft locally, as there is nothing to be moved there. - avoid unbounded descendant computation, and use the faster "rev between" computation. This provide a massive boost to performance when exchanging with repository with a massive amount of draft, like mozilla-try: ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # benchmark.name = hg.command.push # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.explicit-rev = all-out-heads # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.reuse-external-delta-parent = default ## benchmark.variants.revs = any-1-extra-rev before: 20.346590 seconds after: 11.232059 seconds (-38.15%, -7.48 seconds) ## benchmark.variants.revs = any-100-extra-rev before: 24.752051 seconds after: 15.367412 seconds (-37.91%, -9.38 seconds) After this changes, the push operation is still quite too slow. Some of this can be attributed to general phases slowness (reading all the roots from disk for example) and other know slowness (not using persistent-nodemap, branchmap, tags, etc. We are also working on them, but with this series, phase discovery during push no longer showing up in profile and this is a pretty nice and bit low-hanging fruit out of the way. ### (same case as the above) # benchmark.variants.revs = any-1-extra-rev pre-%ln-change: 44.235070 this-changeset: 11.232059 seconds (-74.61%, -33.00 seconds) # benchmark.variants.revs = any-100-extra-rev pre-%ln-change: 49.234697 this-changeset: 15.367412 seconds (-68.79%, -33.87 seconds) Note that with this change, the `hg push` performance is now much closer to the `hg pull` performance, even it still lagging behind a bit. (and the overall performance are still too slow). ### data-env-vars.name = mozilla-try-2023-03-22-ds2-pnm # benchmark.variants.explicit-rev = all-out-heads # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.pulled-delta-reuse-policy = default # bin-env-vars.hg.flavor = rust ## benchmark.variants.revs = any-1-extra-rev hg.command.pull: 6.517450 hg.command.push: 11.219888 ## benchmark.variants.revs = any-100-extra-rev hg.command.pull: 10.160991 hg.command.push: 14.251107 ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # bin-env-vars.hg.py-re2-module = default # benchmark.variants.explicit-rev = all-out-heads # benchmark.variants.issue6528 = disabled # benchmark.variants.protocol = ssh # benchmark.variants.pulled-delta-reuse-policy = default ## bin-env-vars.hg.flavor = default ## benchmark.variants.revs = any-1-extra-rev hg.command.pull: 8.577772 hg.command.push: 11.232059 ## bin-env-vars.hg.flavor = default ## benchmark.variants.revs = any-100-extra-rev hg.command.pull: 13.152976 hg.command.push: 15.367412 ## bin-env-vars.hg.flavor = rust ## benchmark.variants.revs = any-1-extra-rev hg.command.pull: 8.731982 hg.command.push: 11.178751 ## bin-env-vars.hg.flavor = rust ## benchmark.variants.revs = any-100-extra-rev hg.command.pull: 13.184236 hg.command.push: 15.620843

     1

  $ cat >> $HGRCPATH << EOF

     2

  > [storage]

     3

  > dirstate-v2.slow-path=allow

     4

  > [format]

     5

  > use-dirstate-v2=no

     6

  > EOF

     7

     8

Set up a v1 repo

     9

    10

  $ hg init repo

    11

  $ cd repo

    12

  $ echo a > a

    13

  $ touch file-with-somewhat-long-name-to-make-dirstate-v1-bigger-than-v2

    14

  $ hg commit -Aqm a

    15

  $ hg debugrequires | grep dirstate

    16

  [1]

    17

  $ ls -1 .hg/dirstate*

    18

  .hg/dirstate

    19

    20

Copy v1 dirstate

    21

  $ cp .hg/dirstate $TESTTMP/dirstate-v1-backup

    22

    23

Upgrade it to v2

    24

    25

  $ hg debugupgraderepo -q --config format.use-dirstate-v2=1 --run | grep -E 'added:|removed:'

    26

     added: dirstate-v2

    27

  $ hg debugrequires | grep dirstate

    28

  dirstate-v2

    29

  $ ls -1 .hg/dirstate*

    30

  .hg/dirstate

    31

  .hg/dirstate.* (glob)

    32

    33

Manually reset to dirstate v1 to simulate an incomplete dirstate-v2 upgrade

    34

    35

  $ rm .hg/dirstate*

    36

  $ cp $TESTTMP/dirstate-v1-backup .hg/dirstate

    37

    38

There should be no errors, but a v2 dirstate should be written back to disk

    39

  $ hg st

    40

  $ ls -1 .hg/dirstate*

    41

  .hg/dirstate

    42

  .hg/dirstate.* (glob)

    43

    44

Corrupt the dirstate to see how the errors show up to the user

    45

  $ echo "I ate your data" > .hg/dirstate

    46

    47

  $ hg st

    48

  abort: working directory state appears damaged! (no-rhg !)

    49

  (falling back to dirstate-v1 from v2 also failed) (no-rhg !)

    50

  abort: Too little data for dirstate: 16 bytes. (rhg !)

    51

  [255]