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go/internal/lsp/mod/diagnostics.go
Rohan Challa f270e23f6a internal/lsp: add warning diagnostics for unused dependencies in go.mod files
This is the first step to surfacing potential fixes and suggestions to a user's go.mod file. Specifically, it will show a warning if you have a dependency that is not used, or if a dependency is declared as indirect when it should be direct and vice versa.

This CL adds functionality for version of Go that are >= 1.14.

Updates golang/go#31999

Change-Id: Id60fa0ee201dcd843f62e2659dda8e795bd671db
Reviewed-on: https://go-review.googlesource.com/c/tools/+/211937
Run-TryBot: Rohan Challa <rohan@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
2020-01-09 20:05:13 +00:00

94 lines
3.1 KiB
Go

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package mod provides core features related to go.mod file
// handling for use by Go editors and tools.
package mod
import (
"context"
"fmt"
"golang.org/x/mod/modfile"
"golang.org/x/tools/internal/lsp/protocol"
"golang.org/x/tools/internal/lsp/source"
"golang.org/x/tools/internal/lsp/telemetry"
"golang.org/x/tools/internal/telemetry/trace"
)
func Diagnostics(ctx context.Context, snapshot source.Snapshot) (source.FileIdentity, []source.Diagnostic, error) {
// TODO: We will want to support diagnostics for go.mod files even when the -modfile flag is turned off.
realfh, tempfh, err := snapshot.ModFiles(ctx)
if err != nil {
return source.FileIdentity{}, nil, err
}
// Check the case when the tempModfile flag is turned off.
if realfh == nil || tempfh == nil {
return source.FileIdentity{}, nil, nil
}
ctx, done := trace.StartSpan(ctx, "modfiles.Diagnostics", telemetry.File.Of(realfh.Identity().URI))
defer done()
// If the view has a temporary go.mod file, we want to run "go mod tidy" to be able to
// diff between the real and the temp files.
cfg := snapshot.View().Config(ctx)
args := append([]string{"mod", "tidy"}, cfg.BuildFlags...)
if _, err := source.InvokeGo(ctx, snapshot.View().Folder().Filename(), cfg.Env, args...); err != nil {
return source.FileIdentity{}, nil, err
}
realMod, err := snapshot.View().Session().Cache().ParseModHandle(realfh).Parse(ctx)
if err != nil {
return source.FileIdentity{}, nil, err
}
tempMod, err := snapshot.View().Session().Cache().ParseModHandle(tempfh).Parse(ctx)
if err != nil {
return source.FileIdentity{}, nil, err
}
reports := []source.Diagnostic{}
// Check indirect vs direct, and removal of dependencies.
realReqs := make(map[string]*modfile.Require, len(realMod.Require))
tempReqs := make(map[string]*modfile.Require, len(tempMod.Require))
for _, req := range realMod.Require {
realReqs[req.Mod.Path] = req
}
for _, req := range tempMod.Require {
realReq := realReqs[req.Mod.Path]
if realReq != nil && realReq.Indirect == req.Indirect {
delete(realReqs, req.Mod.Path)
}
tempReqs[req.Mod.Path] = req
}
for _, req := range realReqs {
if req.Syntax == nil {
continue
}
dep := req.Mod.Path
diag := &source.Diagnostic{
Message: fmt.Sprintf("%s is not used in this module.", dep),
Source: "go mod tidy",
Range: protocol.Range{Start: getPos(req.Syntax.Start), End: getPos(req.Syntax.End)},
Severity: protocol.SeverityWarning,
}
if tempReqs[dep] != nil && req.Indirect != tempReqs[dep].Indirect {
diag.Message = fmt.Sprintf("%s should be an indirect dependency.", dep)
if req.Indirect {
diag.Message = fmt.Sprintf("%s should not be an indirect dependency.", dep)
}
}
reports = append(reports, *diag)
}
return realfh.Identity(), reports, nil
}
// TODO: Check to see if we need to go through internal/span.
func getPos(pos modfile.Position) protocol.Position {
return protocol.Position{
Line: float64(pos.Line - 1),
Character: float64(pos.LineRune - 1),
}
}