simark added inline comments.
================ Comment at: clangd/ClangdLSPServer.cpp:302 +// FIXME: This function needs to be properly tested. +void ClangdLSPServer::onChangeConfiguration( ---------------- ilya-biryukov wrote: > simark wrote: > > simark wrote: > > > ilya-biryukov wrote: > > > > simark wrote: > > > > > ilya-biryukov wrote: > > > > > > simark wrote: > > > > > > > ilya-biryukov wrote: > > > > > > > > Are you planning to to address this FIXME before checking the > > > > > > > > code in? > > > > > > > Following what you said here: > > > > > > > > > > > > > > https://reviews.llvm.org/D39571?id=124024#inline-359345 > > > > > > > > > > > > > > I have not really looked into what was wrong with the test, and > > > > > > > what is missing in the infrastructure to make it work. But I > > > > > > > assumed that the situation did not change since then. Can you > > > > > > > enlighten me on what the problem was, and what is missing? > > > > > > We usually write unittests for that kind of thing, since they allow > > > > > > to plug an in-memory filesystem, but we only test `ClangdServer` > > > > > > (examples are in `unittests/clangd/ClangdTests.cpp`). > > > > > > `ClangdLSPServer` does not allow to plug in a virtual filesystem > > > > > > (vfs). Even if we add vfs, it's still hard to unit-test because > > > > > > we'll have to match the json input/output directly. > > > > > > > > > > > > This leaves us with an option of a lit test that runs `clangd` > > > > > > directly, similar to tests in `test/clangd`. > > > > > > The lit test would need to create a temporary directory, create > > > > > > proper `compile_commands.json` there, then send the LSP commands > > > > > > with the path to the test to clangd. > > > > > > One major complication is that in LSP we have to specify the size > > > > > > of each message, but in our case the size would change depending on > > > > > > created temp path. It means we'll have to patch the test input to > > > > > > setup proper paths and message sizes. > > > > > > If we choose to go down this path, > > > > > > `clang-tools-extra/test/clang-tidy/vfsoverlay.cpp` does a similar > > > > > > setup (create temp-dir, patch up some configuration files to point > > > > > > into the temp directory, etc) and could be used as a starting point. > > > > > > > > > > > > It's not impossible to write that test, it's just a bit involved. > > > > > > Having a test would be nice, though, to ensure we don't break this > > > > > > method while doing other things. Especially given that this > > > > > > functionality is not used anywhere in clangd. > > > > > > We usually write unittests for that kind of thing, since they allow > > > > > > to plug an in-memory filesystem, but we only test ClangdServer > > > > > > (examples are in unittests/clangd/ClangdTests.cpp). ClangdLSPServer > > > > > > does not allow to plug in a virtual filesystem (vfs). Even if we > > > > > > add vfs, it's still hard to unit-test because we'll have to match > > > > > > the json input/output directly. > > > > > > > > > > What do you mean by "we'll have to match the json input/output > > > > > directly"? That we'll have to match the complete JSON output > > > > > textually? Couldn't the test parse the JSON into some data > > > > > structures, then we could assert specific things, like that this > > > > > particular field is present and contains a certain substring, for > > > > > example? > > > > > > > > > > > This leaves us with an option of a lit test that runs clangd > > > > > > directly, similar to tests in test/clangd. > > > > > > The lit test would need to create a temporary directory, create > > > > > > proper compile_commands.json there, then send the LSP commands with > > > > > > the path to the test to clangd. > > > > > > One major complication is that in LSP we have to specify the size > > > > > > of each message, but in our case the size would change depending on > > > > > > created temp path. It means we'll have to patch the test input to > > > > > > setup proper paths and message sizes. > > > > > > If we choose to go down this path, > > > > > > clang-tools-extra/test/clang-tidy/vfsoverlay.cpp does a similar > > > > > > setup (create temp-dir, patch up some configuration files to point > > > > > > into the temp directory, etc) and could be used as a starting point. > > > > > > > > > > Ok, I see the complication with the Content-Length. I am not > > > > > familiar with lit yet, so I don't know what it is capable of. But > > > > > being able to craft and send arbitrary LSP messages would certainly > > > > > be helpful in the future for all kinds of black box test, so having a > > > > > framework that allows to do this would be helpful, I think. I'm not > > > > > familiar enough with the ecosystem to do this right now, but I'll > > > > > keep it in mind. > > > > > > > > > > One question about this particular test. Would there be some race > > > > > condition here? If we do: > > > > > > > > > > 1. Start clangd with compile_commands.json #1 > > > > > 2. Ask for the definition of a function, expecting a result > > > > > 3. Change the configuration to compile_commands.json #2 > > > > > 4. Ask for the definition of the same function, expecting a different > > > > > result > > > > > > > > > > Since clangd is multi-threaded and does work in the background, are > > > > > we sure that we'll get the result we want in #4? > > > > > > > > > > > It's not impossible to write that test, it's just a bit involved. > > > > > > Having a test would be nice, though, to ensure we don't break this > > > > > > method while doing other things. Especially given that this > > > > > > functionality is not used anywhere in clangd. > > > > > > > > > > I agree. For the time being, is it fine to leave the FIXME there? > > > > > We can work on improving the test frameworks to get rid of it. > > > > > What do you mean by "we'll have to match the json input/output > > > > > directly"? That we'll have to match the complete JSON output > > > > > textually? Couldn't the test parse the JSON into some data > > > > > structures, then we could assert specific things, like that this > > > > > particular field is present and contains a certain substring, for > > > > > example? > > > > > > > > The interface to interact with `ClangdLSPServer` is `JSONOutput`, which > > > > only allows you to pass the output of requests to the stream at the > > > > moment. That means not only parsing json, but also finding the > > > > individual responses in the combined output. > > > > > > > > > One question about this particular test. Would there be some race > > > > > condition here? If we do: > > > > Technically clangd can do everything in parallel, but we have a flag > > > > `-run-synchronously` that will make it do all the work on the main > > > > thread and we use that in the tests. > > > > > > > > LLVM has lots of tests that do substring matches, there's a special > > > > tool, called FileCheck, to make writing them simpler. See the test from > > > > my previous message (specifically the `# CHECK: ` lines), they should > > > > be enough to get started. > > > > Lit itself is a set of python scripts that allow, among other things, > > > > to specify directly in the test file which commands the test needs to > > > > run. Again, see the example tests (specifically, `# RUN: clangd ....` > > > > lines). > > > > > > > > > I agree. For the time being, is it fine to leave the FIXME there? We > > > > > can work on improving the test frameworks to get rid of it. > > > > FIXME looks fine for now, but make sure to test this code does really > > > > work for your use-case. > > > > FIXME looks fine for now, but make sure to test this code does really > > > > work for your use-case. > > > > > > So far I have just tested with some small hello-world projects, but I'll > > > take the time to test with some bigger project (gdb). > > > FIXME looks fine for now, but make sure to test this code does really > > > work for your use-case. > > > > I've tested many scenarios with a project of good size. It works as > > expected, but I've hit the assert in `ClangdServer::forceReparse` maybe > > twice. I don't know how to reproduce it. I think we can go ahead with the > > patch and maybe the problem will become clearer with time. At least even > > if this feature is not completely stable, it won't affect you if you don't > > use it. > What was the assertion? "forceReparse called for non-added document"? > What was the assertion? "forceReparse called for non-added document"? Exactly. Repository: rCTE Clang Tools Extra https://reviews.llvm.org/D39571 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
