gopls/internal/lsp/source/rename: use incremental algorithm

This change is a reimplementation of the renaming operation so
that it no longer mixes types.Objects from different packages.
The basic approach is as follows.

First, the referenced object is found and classified. If it is
nonexported (e.g. lowercase, or inherently local such as an
import or label, or within a function body), the operation is
local to that package and is carried out essentially as before.

However, if it is exported, then the scope of the global search
is deduced (direct for package-level var/func/const/type,
transitive for fields and methods). The object is converted to an
objectpath, and all the reverse dependencies are analyzed, using
the objectpath to identify the target in each package.

The renameObject function (the entry point for the fiddly renamer
algorithm) is now called once per package, and the results of all
calls are combined.

Because we process variants, duplicate edits are likely. We sort
and de-dup at the very end under the assumption that edits are
well behaved. The "seen edit" tracking in package renaming is no
longer needed.

Also:
- Package.importMap maps PackagePath to Package for all dependencies,
  so that we can resolve targets identified by (PackagePath,
  objectpath) to their objects in a different types.Importer "realm".
  It is materialized as a DAG of k/v pairs and exposed as
  Package.DependencyTypes.
- The rename_check algorithm (renamer) is now applied once to each
  package instead of once to all packages.
- The set of references to update is derived from types.Info, not the
  references operation.

Still to do in follow-ups:
- Method renaming needs to expand the set of renamed types (based on
  'satisfy') and recompute the dependencies of their declarations,
  until a fixed point is reached. (Not supporting this case is a
  functional regression since v0.11.0, but we plan to submit this
  change to unblock foundational progress and then fix it before the
  next release. See golang/go#58461)
- Lots of generics cases to consider (see golang/go#58462).
- Lots more tests required. For golang/go#57987.

Change-Id: I5fd8538ab35d61744d765d8bd101cd4efa41bd33
Reviewed-on: https://go-review.googlesource.com/c/tools/+/464902
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
11 files changed
tree: c87227fcaa55007ef000492c8bfa9f51acf1298b
  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.