branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
#require test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ testrepohgenv
$ import_checker="$TESTDIR"/../contrib/import-checker.py
Run the doctests from the import checker, and make sure
it's working correctly.
$ TERM=dumb
$ export TERM
$ "$PYTHON" -m doctest $import_checker
Run additional tests for the import checker
$ mkdir testpackage
$ touch testpackage/__init__.py
$ cat > testpackage/multiple.py << EOF
> import os, sys
> EOF
$ cat > testpackage/unsorted.py << EOF
> import sys
> import os
> EOF
$ cat > testpackage/stdafterlocal.py << EOF
> from . import unsorted
> import os
> EOF
$ cat > testpackage/requirerelative.py << EOF
> import testpackage.unsorted
> EOF
$ cat > testpackage/importalias.py << EOF
> import ui
> EOF
$ cat > testpackage/relativestdlib.py << EOF
> from .. import os
> EOF
$ cat > testpackage/stdlibfrom.py << EOF
> from collections import abc
> EOF
$ cat > testpackage/symbolimport.py << EOF
> from .unsorted import foo
> EOF
$ cat > testpackage/latesymbolimport.py << EOF
> from . import unsorted
> from mercurial.node import hex
> EOF
$ cat > testpackage/multiplegroups.py << EOF
> from . import unsorted
> from . import more
> EOF
$ mkdir testpackage/subpackage
$ cat > testpackage/subpackage/levelpriority.py << EOF
> from . import foo
> from .. import parent
> EOF
$ touch testpackage/subpackage/foo.py
$ cat > testpackage/subpackage/__init__.py << EOF
> from . import levelpriority # should not cause cycle
> EOF
$ cat > testpackage/subpackage/localimport.py << EOF
> from . import foo
> def bar():
> # should not cause "higher-level import should come first"
> from .. import unsorted
> # but other errors should be detected
> from .. import more
> import testpackage.subpackage.levelpriority
> EOF
$ cat > testpackage/importmodulefromsub.py << EOF
> from .subpackage import foo # not a "direct symbol import"
> EOF
$ cat > testpackage/importsymbolfromsub.py << EOF
> from .subpackage import foo, nonmodule
> EOF
$ cat > testpackage/sortedentries.py << EOF
> from . import (
> foo,
> bar,
> )
> EOF
$ cat > testpackage/importfromalias.py << EOF
> from . import ui
> EOF
$ cat > testpackage/importfromrelative.py << EOF
> from testpackage.unsorted import foo
> EOF
$ mkdir testpackage2
$ touch testpackage2/__init__.py
$ cat > testpackage2/latesymbolimport.py << EOF
> from testpackage import unsorted
> from mercurial.node import hex
> EOF
# Shadowing a stdlib module to test "relative import of stdlib module" is
# allowed if the module is also being checked
$ mkdir email
$ touch email/__init__.py
$ touch email/errors.py
$ cat > email/utils.py << EOF
> from . import errors
> EOF
$ "$PYTHON" "$import_checker" testpackage*/*.py testpackage/subpackage/*.py \
> email/*.py
testpackage/importalias.py:1: ui module must be "as" aliased to uimod
testpackage/importfromalias.py:1: ui from testpackage must be "as" aliased to uimod
testpackage/importfromrelative.py:1: import should be relative: testpackage.unsorted
testpackage/importfromrelative.py:1: direct symbol import foo from testpackage.unsorted
testpackage/importsymbolfromsub.py:1: direct symbol import nonmodule from testpackage.subpackage
testpackage/latesymbolimport.py:2: symbol import follows non-symbol import: mercurial.node
testpackage/multiple.py:1: multiple imported names: os, sys
testpackage/multiplegroups.py:2: multiple "from . import" statements
testpackage/relativestdlib.py:1: relative import of stdlib module
testpackage/requirerelative.py:1: import should be relative: testpackage.unsorted
testpackage/sortedentries.py:1: imports from testpackage not lexically sorted: bar < foo
testpackage/stdafterlocal.py:2: stdlib import "os" follows local import: testpackage
testpackage/stdlibfrom.py:1: direct symbol import abc from collections
testpackage/subpackage/levelpriority.py:2: higher-level import should come first: testpackage
testpackage/subpackage/localimport.py:6: multiple "from .. import" statements
testpackage/subpackage/localimport.py:7: import should be relative: testpackage.subpackage.levelpriority
testpackage/symbolimport.py:1: direct symbol import foo from testpackage.unsorted
testpackage/unsorted.py:2: imports not lexically sorted: os < sys
testpackage2/latesymbolimport.py:2: symbol import follows non-symbol import: mercurial.node
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