view contrib/perf-utils/subsetmaker.py @ 49248:63fd0282ad40

node: stop converting binascii.Error to TypeError in bin()

Changeset f574cc00831a introduced the wrapper, to make bin() behave like on
Python 2, where it raised TypeError in many cases. Another previous approach,
changing callers to catch binascii.Error in addition to TypeError, was backed
out after negative review feedback [1].

However, I think it’s worth reconsidering the approach. Now that we’re on
Python 3 only, callers have to catch only binascii.Error instead of both.
Catching binascii.Error instead of TypeError has the advantage that it’s less
likely to cover a programming error (e.g. passing an int to bin() raises
TypeError). Also, raising TypeError never made sense semantically when bin()
got an argument of valid type.

As a side-effect, this fixed an exception in test-http-bad-server.t. The TODO
was outdated: it was not an uncaught ValueError in batch.results() but uncaught
TypeError from the now removed wrapper. Now that bin() raises binascii.Error
instead of TypeError, it gets converted to a proper error in
wirepeer.heads.<locals>.decode() that catches ValueError (superclass of
binascii.Error). This is a good example of why this changeset is a good idea.
Catching TypeError instead of ValueError there would not make much sense.

[1] https://phab.mercurial-scm.org/D2244

"""revset to select sample of repository

Hopefully this is useful to create interesting discovery cases.
"""

import collections
import random

from mercurial.i18n import _

from mercurial import (
    registrar,
    revset,
    revsetlang,
    smartset,
)

import sortedcontainers

SortedSet = sortedcontainers.SortedSet

revsetpredicate = registrar.revsetpredicate()


@revsetpredicate(b'subsetspec("<spec>")')
def subsetmarkerspec(repo, subset, x):
    """use a shorthand spec as used by search-discovery-case

    Supported format are:

    - "scratch-count-seed": not scratch(all(), count, "seed")
    - "randomantichain-seed": ::randomantichain(all(), "seed")
    - "rev-REV": "::REV"
    """
    args = revsetlang.getargs(
        x, 0, 1, _(b'subsetspec("spec") required an argument')
    )

    spec = revsetlang.getstring(args[0], _(b"spec should be a string"))
    case = spec.split(b'-')
    t = case[0]
    if t == b'scratch':
        spec_revset = b'not scratch(all(), %s, "%s")' % (case[1], case[2])
    elif t == b'randomantichain':
        spec_revset = b'::randomantichain(all(), "%s")' % case[1]
    elif t == b'rev':
        spec_revset = b'::%d' % case[1]
    else:
        assert False, spec

    selected = repo.revs(spec_revset)

    return selected & subset


@revsetpredicate(b'scratch(REVS, <count>, [seed])')
def scratch(repo, subset, x):
    """randomly remove <count> revision from the repository top

    This subset is created by recursively picking changeset starting from the
    heads. It can be summarized using the following algorithm::

        selected = set()
        for i in range(<count>):
            unselected = repo.revs("not <selected>")
            candidates = repo.revs("heads(<unselected>)")
            pick = random.choice(candidates)
            selected.add(pick)
    """
    m = _(b"scratch expects revisions, count argument and an optional seed")
    args = revsetlang.getargs(x, 2, 3, m)
    if len(args) == 2:
        x, n = args
        rand = random
    elif len(args) == 3:
        x, n, seed = args
        seed = revsetlang.getinteger(seed, _(b"seed should be a number"))
        rand = random.Random(seed)
    else:
        assert False

    n = revsetlang.getinteger(n, _(b"scratch expects a number"))

    selected = set()
    heads = SortedSet()
    children_count = collections.defaultdict(lambda: 0)
    parents = repo.changelog._uncheckedparentrevs

    baseset = revset.getset(repo, smartset.fullreposet(repo), x)
    baseset.sort()
    for r in baseset:
        heads.add(r)

        p1, p2 = parents(r)
        if p1 >= 0:
            heads.discard(p1)
            children_count[p1] += 1
        if p2 >= 0:
            heads.discard(p2)
            children_count[p2] += 1

    for h in heads:
        assert children_count[h] == 0

    selected = set()
    for x in range(n):
        if not heads:
            break
        pick = rand.choice(heads)
        heads.remove(pick)
        assert pick not in selected
        selected.add(pick)
        p1, p2 = parents(pick)
        if p1 in children_count:
            assert p1 in children_count
            children_count[p1] -= 1
            assert children_count[p1] >= 0
            if children_count[p1] == 0:
                assert p1 not in selected, (r, p1)
                heads.add(p1)
        if p2 in children_count:
            assert p2 in children_count
            children_count[p2] -= 1
            assert children_count[p2] >= 0
            if children_count[p2] == 0:
                assert p2 not in selected, (r, p2)
                heads.add(p2)

    return smartset.baseset(selected) & subset


@revsetpredicate(b'randomantichain(REVS, [seed])')
def antichain(repo, subset, x):
    """Pick a random anti-chain in the repository

    A antichain is a set of changeset where there isn't any element that is
    either a descendant or ancestors of any other element in the set. In other
    word, all the elements are independant. It can be summarized with the
    following algorithm::

    selected = set()
    unselected = repo.revs('all()')
    while unselected:
        pick = random.choice(unselected)
        selected.add(pick)
        unselected -= repo.revs('::<pick> + <pick>::')
    """

    args = revsetlang.getargs(
        x, 1, 2, _(b"randomantichain expects revisions and an optional seed")
    )
    if len(args) == 1:
        (x,) = args
        rand = random
    elif len(args) == 2:
        x, seed = args
        seed = revsetlang.getinteger(seed, _(b"seed should be a number"))
        rand = random.Random(seed)
    else:
        assert False

    cl = repo.changelog

    # We already have cheap access to the parent mapping.
    # However, we need to build a mapping of the children mapping
    parents = repo.changelog._uncheckedparentrevs
    children_map = collections.defaultdict(list)
    for r in cl:
        p1, p2 = parents(r)
        if p1 >= 0:
            children_map[p1].append(r)
        if p2 >= 0:
            children_map[p2].append(r)
    children = children_map.__getitem__

    selected = set()
    undecided = SortedSet(cl)

    while undecided:
        # while there is "undecided content", we pick a random changeset X
        # and we remove anything in `::X + X::` from undecided content
        pick = rand.choice(undecided)
        selected.add(pick)
        undecided.remove(pick)

        ancestors = set(p for p in parents(pick) if p in undecided)
        descendants = set(c for c in children(pick) if c in undecided)

        while ancestors:
            current = ancestors.pop()
            undecided.remove(current)
            for p in parents(current):
                if p in undecided:
                    ancestors.add(p)
        while descendants:
            current = descendants.pop()
            undecided.remove(current)
            for p in children(current):
                if p in undecided:
                    ancestors.add(p)

    return smartset.baseset(selected) & subset