hghave: allow adding customized features at runtime
Before this patch, there is no way to add customized features to
`hghave` without changing `hghave` and `hghave.py` themselves.
This decreases reusability of `run-tests.py` framework for third party
tools, because they may want to examine custom features at runtime
(e.g. existence of some external tools).
To allow adding customized features at runtime, this patch makes
`hghave` import `hghaveaddon` module, only when `hghaveaddon.py` file
can be found in directories below:
- `TESTDIR` for invocation via `run-tests.py`
- `.` for invocation via command line
The path to the directory where `hghaveaddon.py` should be placed is
added to `sys.path` only while importing `hghaveaddon`, because:
- `.` may not be added to `PYTHONPATH`
- adding additional path to `sys.path` may change behavior of
subsequent `import` for other features
`hghave` is terminated with exit code '2' at failure of `import
hghaveaddon`, because exit code '2' terminates `run-tests.py`
immediately.
This is a one of preparations for issue4677.
=== property cache ===
calllog: []
cached value (unfiltered): NOCACHE
= first access on unfiltered, should do a call
access: 0
calllog: [0]
cached value (unfiltered): 0
= second access on unfiltered, should not do call
access 0
calllog: [0]
cached value (unfiltered): 0
= first access on "visible" view, should do a call
cached value ("visible" view): NOCACHE
access: 7
calllog: [0, 7]
cached value (unfiltered): 0
cached value ("visible" view): 7
= second access on "visible view", should not do call
access: 7
calllog: [0, 7]
cached value (unfiltered): 0
cached value ("visible" view): 7
= no effect on other view
cached value ("immutable" view): NOCACHE
access: 9
calllog: [0, 7, 9]
cached value (unfiltered): 0
cached value ("visible" view): 7
cached value ("immutable" view): 9
=== unfiltered property cache ===
unficalllog: []
cached value (unfiltered): NOCACHE
cached value ("visible" view): NOCACHE
cached value ("immutable" view): NOCACHE
= first access on unfiltered, should do a call
access (unfiltered): 100
unficalllog: [100]
cached value (unfiltered): 100
= second access on unfiltered, should not do call
access (unfiltered): 100
unficalllog: [100]
cached value (unfiltered): 100
= access on view should use the unfiltered cache
access (unfiltered): 100
access ("visible" view): 100
access ("immutable" view): 100
unficalllog: [100]
cached value (unfiltered): 100
cached value ("visible" view): NOCACHE
cached value ("immutable" view): NOCACHE
= even if we clear the unfiltered cache
cached value (unfiltered): NOCACHE
cached value ("visible" view): NOCACHE
cached value ("immutable" view): NOCACHE
unficalllog: [100]
access ("visible" view): 100
unficalllog: [100, 100]
cached value (unfiltered): 100
cached value ("visible" view): NOCACHE
cached value ("immutable" view): NOCACHE
access ("immutable" view): 100
unficalllog: [100, 100]
cached value (unfiltered): 100
cached value ("visible" view): NOCACHE
cached value ("immutable" view): NOCACHE
access (unfiltered): 100
unficalllog: [100, 100]
cached value (unfiltered): 100
cached value ("visible" view): NOCACHE
cached value ("immutable" view): NOCACHE