Rob Findley d463eb0e41 internal/lsp/cache: introduce a workspace abstraction ... When incorporating the gopls.mod file, the invalidation logic for workspace module information becomes quite complicated. For example: + if a modfile changes we should only invalidate if it is in the set of active modules + the set of active modules can be provided by either the filesystem or gopls.mod + if gopls.mod changes, we may gain or lose active modules in the workspace + if gopls.mod is *deleted*, we may need to walk the filesystem to actually find all active modules Doing this with only concrete changes to the snapshot proved prohibitively complex (at least for me), so a new workspace type is introduced to manage the module state. This new abstraction is responsible for tracking the set of active modules, the workspace modfile, and the set of workspace directories. Its invalidation logic is factored out of snapshot.clone, so that it can be tested and to alleviate some of the growing complexity of snapshot.clone. The workspace type is idempotent, allowing it to be shared across snapshots without needing to use the cache. There is little benefit to the cache in this case, since workspace module computation should be infrequent, and the type itself consumes little memory. This is made possible because the workspace type itself depends only on file state, and therefore may be invalidated independently of the snapshot. The new source.FileState interface is used in testing, and so that the workspace module may be computed based on both the session file state as well as the snapshot file state. As a result of this change, the following improvements in functionality are possible: + in the presence of a gopls.mod file, we avoid walking the filesystem to detect modules. This could be helpful for working in large monorepos or in GOPATH, when discovering all modules would be expensive. + The set of active modules should always be consistent with the gopls.mod file, likely fixing some bugs (for example, computing diagnostics for modfiles that shouldn't be loaded) For golang/go#41837 Change-Id: I2da888c097748b659ee892ca2d6b3fbe29c1942e Reviewed-on: https://go-review.googlesource.com/c/tools/+/261237 Run-TryBot: Robert Findley <rfindley@google.com> gopls-CI: kokoro <noreply+kokoro@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Heschi Kreinick <heschi@google.com> Trust: Robert Findley <rfindley@google.com>		2020-10-30 19:58:30 +00:00
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hooks	internal/lsp: pass options by reference instead of by value	2020-09-16 22:53:23 +00:00
regtest	internal/lsp/cache: introduce a workspace abstraction	2020-10-30 19:58:30 +00:00