The API digester tests were being run only for macOS, mainly
because they were not using %target-swift consistently. Lift
the unnecessary restriction so we run these tests more widely.
LLVM's lit implementation switched to use process pools in r299775.
This exposed some pickling problems in Swift's lit files. For a function
or class to be pickle-able, it has to be in the top-level of a real
Python module.
* The SwiftTest lit format class was embedded in the lit.cfg file, so
I moved it out to a separate Python file.
* The inferSwiftBinary function was being stashed in the
config.inferSwiftBinary field and later used to find tools for SourceKit
testing. I moved the config settings for those tools into the top-level
lit.cfg file. I expect this will cause warnings about them not existing
in some cases, but that should be fairly harmless. Maybe someone can
come up with a better solution later.
* The config.substitutions for SourceKit's lit.local.cfg was storing a
reference to an embedded sed_clean function, which just returned a
constant string. I changed the function to be a string, using Python's
raw string feature to avoid the problems that likely led to it being a
function in the first place. (Just guessing.)
[Tools] Add a tool to detect source-breaking API changes introduced from libraries.
swift-api-digester is a test utility to detect source-breaking API changes
during the evolution of a swift library. The tool works on two phases:
(1) dumping library contents as a json file, and (2) comparing two json
files textually to report interesting changes.
During phase (1), the api-digester looks up every declarations inside
a module and outputs a singly-rooted tree that encloses interesting
details of the API level.
During phase (2), api-digester applies structure-information comparision
algorithms on two given singly root trees, trying to figure out, as
precise as possible, the branches/leaves in the trees that differ from
each other. Further analysis decides whether the changed leaves/branches
can be reflected as source-breaking changes for API users. If they are,
the output of api-digester will include such changes.
Also, this commit includes a regression test that make sure API changes
from the Swift stdlib are expected.
