tests/test-propertycache.py

filemerge: add support for partial conflict resolution by external tool

A common class of merge conflicts is in imports/#includes/etc. It's
relatively easy to write a tool that can resolve these conflicts,
perhaps by naively just unioning the statements and leaving any
cleanup to other tools to do later [1]. Such specialized tools cannot
generally resolve all conflicts in a file, of course. Let's therefore
call them "partial merge tools". Note that the internal simplemerge
algorithm is such a partial merge tool - one that only resolves
trivial "conflicts" where one side is unchanged or both sides change
in the same way.

One can also imagine having smarter language-aware partial tools that
merge the AST. It may be useful for such tools to interactively let
the user resolve any conflicts it can't resolve itself. However,
having the option of implementing it as a partial merge tool means
that the developer doesn't *need* to create a UI for it. Instead, the
user can resolve any remaining conflicts with their regular merge tool
(e.g. `:merge3` or `meld).

We don't currently have a way to let the user define such partial
merge tools. That's what this patch addresses. It lets the user
configure partial merge tools to run. Each tool can be configured to
run only on files matching certain patterns (e.g. "*.py"). The tool
takes three inputs (local, base, other) and resolves conflicts by
updating these in place. For example, let's say the inputs are these:


base:
```
import sys

def main():
  print('Hello')
```

local:
```
import os
import sys

def main():
  print('Hi')
```

other:
```
import re
import sys

def main():
  print('Howdy')
```

A partial merge tool could now resolve the conflicting imports by
replacing the import statements in *all* files by the following
snippet, while leaving the remainder of the files unchanged.

```
import os
import re
import sys
```

As a result, simplemerge and any regular merge tool that runs after
the partial merge tool(s) will consider the imports to be
non-conflicting and will only present the conflict in `main()` to the
user.

Differential Revision: https://phab.mercurial-scm.org/D12356

"""test behavior of propertycache and unfiltered propertycache

The repoview overlay is quite complex. We test the behavior of
property cache of both localrepo and repoview to prevent
regression."""

import os
import subprocess

from mercurial import (
    hg,
    localrepo,
    pycompat,
    ui as uimod,
    util,
)

from mercurial.utils import procutil

# create some special property cache that trace they call

calllog = []


@util.propertycache
def testcachedfoobar(repo):
    name = repo.filtername
    if name is None:
        name = ''
    val = len(name)
    calllog.append(val)
    return val


unficalllog = []


@localrepo.unfilteredpropertycache
def testcachedunfifoobar(repo):
    name = repo.filtername
    if name is None:
        name = ''
    val = 100 + len(name)
    unficalllog.append(val)
    return val


# plug them on repo
localrepo.localrepository.testcachedfoobar = testcachedfoobar
localrepo.localrepository.testcachedunfifoobar = testcachedunfifoobar


# Create an empty repo and instantiate it. It is important to run
# these tests on the real object to detect regression.
repopath = pycompat.fsencode(os.path.join(os.environ['TESTTMP'], 'repo'))
assert (
    subprocess.call(
        pycompat.rapply(procutil.tonativestr, [b'hg', b'init', repopath])
    )
    == 0
)

ui = uimod.ui.load()
repo = hg.repository(ui, path=repopath).unfiltered()


print('')
print('=== property cache ===')
print('')
print('calllog:', calllog)
print(
    'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)

print('')
print('= first access on unfiltered, should do a call')
print('access:', repo.testcachedfoobar)
print('calllog:', calllog)
print(
    'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)

print('')
print('= second access on unfiltered, should not do call')
print('access', repo.testcachedfoobar)
print('calllog:', calllog)
print(
    'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)

print('')
print('= first access on "visible" view, should do a call')
visibleview = repo.filtered('visible')
print(
    'cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'),
)
print('access:', visibleview.testcachedfoobar)
print('calllog:', calllog)
print(
    'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print(
    'cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'),
)

print('')
print('= second access on "visible view", should not do call')
print('access:', visibleview.testcachedfoobar)
print('calllog:', calllog)
print(
    'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print(
    'cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'),
)

print('')
print('= no effect on other view')
immutableview = repo.filtered('immutable')
print(
    'cached value ("immutable" view):',
    vars(immutableview).get('testcachedfoobar', 'NOCACHE'),
)
print('access:', immutableview.testcachedfoobar)
print('calllog:', calllog)
print(
    'cached value (unfiltered):', vars(repo).get('testcachedfoobar', 'NOCACHE')
)
print(
    'cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'),
)
print(
    'cached value ("immutable" view):',
    vars(immutableview).get('testcachedfoobar', 'NOCACHE'),
)

# unfiltered property cache test
print('')
print('')
print('=== unfiltered property cache ===')
print('')
print('unficalllog:', unficalllog)
print(
    'cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)

print('')
print('= first access on unfiltered, should do a call')
print('access (unfiltered):', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
    'cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)

print('')
print('= second access on unfiltered, should not do call')
print('access (unfiltered):', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
    'cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)

print('')
print('= access on view should use the unfiltered cache')
print('access (unfiltered):      ', repo.testcachedunfifoobar)
print('access ("visible" view):  ', visibleview.testcachedunfifoobar)
print('access ("immutable" view):', immutableview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
    'cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)

print('')
print('= even if we clear the unfiltered cache')
del repo.__dict__['testcachedunfifoobar']
print(
    'cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)
print('unficalllog:', unficalllog)
print('access ("visible" view):  ', visibleview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
    'cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)
print('access ("immutable" view):', immutableview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
    'cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)
print('access (unfiltered):      ', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print(
    'cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'),
)
print(
    'cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'),
)