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go / tools / 3e9483071c531291075b9d7ce66ff09218ed8d5a
commit3e9483071c531291075b9d7ce66ff09218ed8d5a[log] [tgz]
authorRob Findley <rfindley@google.com>Mon Jun 10 18:41:47 2024 +0000
committerRobert Findley <rfindley@google.com>Tue Jun 11 18:12:06 2024 +0000
tree5025d508496a7ed91f63f29b5ab6d69c4c947c99
parentdddd55df4919cb0fab2ab5c30445f358a39da8fb [diff]
internal/imports: optimize package path filtering

As reported in golang/go#67889, a short unresolved identifier can cause
goimports fixes to be quite slow, because the substring match heuristic
used to filter import paths matches a large fraction of the module
cache.

Fix this by improving the precision of the matching heuristic used to
filter potential packages. We now match only full segments of the import
path (ignoring '.' and '-'), or subsegments delimited by '.' and '-'.

Add a gopls benchmark that reproduces this initial slowness, along with
a command to force a scan of the module cache. On my (overpowered) linux
development machine, with a 5GB module cache, this change reduces the
benchmark time ~90%, from 2s to 200ms. With a smaller machine, slower
operating system, or larger module cache, I imagine the starting
point could be significantly more than 2s.

Fixes golang/go#67889

Change-Id: Id8f7ea20040b059b42366333adeb4add684dee61
Reviewed-on: https://go-review.googlesource.com/c/tools/+/591715
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
10 files changed
tree: 5025d508496a7ed91f63f29b5ab6d69c4c947c99
  1. benchmark/
  2. blog/
  3. cmd/
  4. container/
  5. copyright/
  6. cover/
  7. go/
  8. godoc/
  9. gopls/
  10. imports/
  11. internal/
  12. playground/
  13. present/
  14. refactor/
  15. txtar/
  16. .gitattributes
  17. .gitignore
  18. .prettierrc
  19. codereview.cfg
  20. CONTRIBUTING.md
  21. go.mod
  22. go.sum
  23. LICENSE
  24. PATENTS
  25. README.md
README.md

Go Tools

PkgGoDev

This repository provides the golang.org/x/tools module, comprising various tools and packages mostly for static analysis of Go programs, some of which are listed below. Use the “Go reference” link above for more information about any package.

It also contains the golang.org/x/tools/gopls module, whose root package is a language-server protocol (LSP) server for Go. An LSP server analyses the source code of a project and responds to requests from a wide range of editors such as VSCode and Vim, allowing them to support IDE-like functionality.

Selected commands:

  • cmd/goimports formats a Go program like go fmt and additionally inserts import statements for any packages required by the file after it is edited.
  • cmd/callgraph prints the call graph of a Go program.
  • cmd/digraph is a utility for manipulating directed graphs in textual notation.
  • cmd/stringer generates declarations (including a String method) for “enum” types.
  • cmd/toolstash is a utility to simplify working with multiple versions of the Go toolchain.

These commands may be fetched with a command such as

go install golang.org/x/tools/cmd/goimports@latest

Selected packages:

  • go/ssa provides a static single-assignment form (SSA) intermediate representation (IR) for Go programs, similar to a typical compiler, for use by analysis tools.

  • go/packages provides a simple interface for loading, parsing, and type checking a complete Go program from source code.

  • go/analysis provides a framework for modular static analysis of Go programs.

  • go/callgraph provides call graphs of Go programs using a variety of algorithms with different trade-offs.

  • go/ast/inspector provides an optimized means of traversing a Go parse tree for use in analysis tools.

  • go/cfg provides a simple control-flow graph (CFG) for a Go function.

  • go/expect reads Go source files used as test inputs and interprets special comments within them as queries or assertions for testing.

  • go/gcexportdata and go/gccgoexportdata read and write the binary files containing type information used by the standard and gccgo compilers.

  • go/types/objectpath provides a stable naming scheme for named entities (“objects”) in the go/types API.

Numerous other packages provide more esoteric functionality.

Contributing

This repository uses Gerrit for code changes. To learn how to submit changes, see https://golang.org/doc/contribute.html.

The main issue tracker for the tools repository is located at https://github.com/golang/go/issues. Prefix your issue with “x/tools/(your subdir):” in the subject line, so it is easy to find.

JavaScript and CSS Formatting

This repository uses prettier to format JS and CSS files.

The version of prettier used is 1.18.2.

It is encouraged that all JS and CSS code be run through this before submitting a change. However, it is not a strict requirement enforced by CI.