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// Copyright 2020 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 cache
import (
"context"
"fmt"
"go/ast"
"go/token"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"golang.org/x/mod/modfile"
"golang.org/x/tools/gopls/internal/lsp/command"
"golang.org/x/tools/gopls/internal/lsp/protocol"
"golang.org/x/tools/gopls/internal/lsp/source"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/event/tag"
"golang.org/x/tools/internal/gocommand"
"golang.org/x/tools/internal/memoize"
"golang.org/x/tools/internal/span"
)
// ModTidy returns the go.mod file that would be obtained by running
// "go mod tidy". Concurrent requests are combined into a single command.
func (s *snapshot) ModTidy(ctx context.Context, pm *source.ParsedModule) (*source.TidiedModule, error) {
uri := pm.URI
if pm.File == nil {
return nil, fmt.Errorf("cannot tidy unparseable go.mod file: %v", uri)
}
s.mu.Lock()
entry, hit := s.modTidyHandles.Get(uri)
s.mu.Unlock()
type modTidyResult struct {
tidied *source.TidiedModule
err error
}
// Cache miss?
if !hit {
// If the file handle is an overlay, it may not be written to disk.
// The go.mod file has to be on disk for `go mod tidy` to work.
// TODO(rfindley): is this still true with Go 1.16 overlay support?
fh, err := s.GetFile(ctx, pm.URI)
if err != nil {
return nil, err
}
if _, ok := fh.(*overlay); ok {
if info, _ := os.Stat(uri.Filename()); info == nil {
return nil, source.ErrNoModOnDisk
}
}
if criticalErr := s.GetCriticalError(ctx); criticalErr != nil {
return &source.TidiedModule{
Diagnostics: criticalErr.Diagnostics,
}, nil
}
if err := s.awaitLoaded(ctx); err != nil {
return nil, err
}
handle := memoize.NewPromise("modTidy", func(ctx context.Context, arg interface{}) interface{} {
tidied, err := modTidyImpl(ctx, arg.(*snapshot), uri.Filename(), pm)
return modTidyResult{tidied, err}
})
entry = handle
s.mu.Lock()
s.modTidyHandles.Set(uri, entry, nil)
s.mu.Unlock()
}
// Await result.
v, err := s.awaitPromise(ctx, entry.(*memoize.Promise))
if err != nil {
return nil, err
}
res := v.(modTidyResult)
return res.tidied, res.err
}
// modTidyImpl runs "go mod tidy" on a go.mod file.
func modTidyImpl(ctx context.Context, snapshot *snapshot, filename string, pm *source.ParsedModule) (*source.TidiedModule, error) {
ctx, done := event.Start(ctx, "cache.ModTidy", tag.URI.Of(filename))
defer done()
inv := &gocommand.Invocation{
Verb: "mod",
Args: []string{"tidy"},
WorkingDir: filepath.Dir(filename),
}
// TODO(adonovan): ensure that unsaved overlays are passed through to 'go'.
tmpURI, inv, cleanup, err := snapshot.goCommandInvocation(ctx, source.WriteTemporaryModFile, inv)
if err != nil {
return nil, err
}
// Keep the temporary go.mod file around long enough to parse it.
defer cleanup()
if _, err := snapshot.view.session.gocmdRunner.Run(ctx, *inv); err != nil {
return nil, err
}
// Go directly to disk to get the temporary mod file,
// since it is always on disk.
tempContents, err := ioutil.ReadFile(tmpURI.Filename())
if err != nil {
return nil, err
}
ideal, err := modfile.Parse(tmpURI.Filename(), tempContents, nil)
if err != nil {
// We do not need to worry about the temporary file's parse errors
// since it has been "tidied".
return nil, err
}
// Compare the original and tidied go.mod files to compute errors and
// suggested fixes.
diagnostics, err := modTidyDiagnostics(ctx, snapshot, pm, ideal)
if err != nil {
return nil, err
}
return &source.TidiedModule{
Diagnostics: diagnostics,
TidiedContent: tempContents,
}, nil
}
// modTidyDiagnostics computes the differences between the original and tidied
// go.mod files to produce diagnostic and suggested fixes. Some diagnostics
// may appear on the Go files that import packages from missing modules.
func modTidyDiagnostics(ctx context.Context, snapshot *snapshot, pm *source.ParsedModule, ideal *modfile.File) (diagnostics []*source.Diagnostic, err error) {
// First, determine which modules are unused and which are missing from the
// original go.mod file.
var (
unused = make(map[string]*modfile.Require, len(pm.File.Require))
missing = make(map[string]*modfile.Require, len(ideal.Require))
wrongDirectness = make(map[string]*modfile.Require, len(pm.File.Require))
)
for _, req := range pm.File.Require {
unused[req.Mod.Path] = req
}
for _, req := range ideal.Require {
origReq := unused[req.Mod.Path]
if origReq == nil {
missing[req.Mod.Path] = req
continue
} else if origReq.Indirect != req.Indirect {
wrongDirectness[req.Mod.Path] = origReq
}
delete(unused, req.Mod.Path)
}
for _, req := range wrongDirectness {
// Handle dependencies that are incorrectly labeled indirect and
// vice versa.
srcDiag, err := directnessDiagnostic(pm.Mapper, req, snapshot.View().Options().ComputeEdits)
if err != nil {
// We're probably in a bad state if we can't compute a
// directnessDiagnostic, but try to keep going so as to not suppress
// other, valid diagnostics.
event.Error(ctx, "computing directness diagnostic", err)
continue
}
diagnostics = append(diagnostics, srcDiag)
}
// Next, compute any diagnostics for modules that are missing from the
// go.mod file. The fixes will be for the go.mod file, but the
// diagnostics should also appear in both the go.mod file and the import
// statements in the Go files in which the dependencies are used.
missingModuleFixes := map[*modfile.Require][]source.SuggestedFix{}
for _, req := range missing {
srcDiag, err := missingModuleDiagnostic(pm, req)
if err != nil {
return nil, err
}
missingModuleFixes[req] = srcDiag.SuggestedFixes
diagnostics = append(diagnostics, srcDiag)
}
// Add diagnostics for missing modules anywhere they are imported in the
// workspace.
// TODO(adonovan): opt: opportunities for parallelism abound.
for _, id := range snapshot.workspacePackageIDs() {
m := snapshot.getMetadata(id)
if m == nil {
return nil, fmt.Errorf("no metadata for %s", id)
}
// Read both lists of files of this package, in parallel.
goFiles, compiledGoFiles, err := readGoFiles(ctx, snapshot, m.Metadata)
if err != nil {
return nil, err
}
missingImports := map[string]*modfile.Require{}
// If -mod=readonly is not set we may have successfully imported
// packages from missing modules. Otherwise they'll be in
// MissingDependencies. Combine both.
for imp := range parseImports(ctx, snapshot, goFiles) {
if req, ok := missing[imp]; ok {
missingImports[imp] = req
break
}
// If the import is a package of the dependency, then add the
// package to the map, this will eliminate the need to do this
// prefix package search on each import for each file.
// Example:
//
// import (
// "golang.org/x/tools/go/expect"
// "golang.org/x/tools/go/packages"
// )
// They both are related to the same module: "golang.org/x/tools".
var match string
for _, req := range ideal.Require {
if strings.HasPrefix(imp, req.Mod.Path) && len(req.Mod.Path) > len(match) {
match = req.Mod.Path
}
}
if req, ok := missing[match]; ok {
missingImports[imp] = req
}
}
// None of this package's imports are from missing modules.
if len(missingImports) == 0 {
continue
}
for _, goFile := range compiledGoFiles {
pgf, err := snapshot.ParseGo(ctx, goFile, source.ParseHeader)
if err != nil {
continue
}
file, m := pgf.File, pgf.Mapper
if file == nil || m == nil {
continue
}
imports := make(map[string]*ast.ImportSpec)
for _, imp := range file.Imports {
if imp.Path == nil {
continue
}
if target, err := strconv.Unquote(imp.Path.Value); err == nil {
imports[target] = imp
}
}
if len(imports) == 0 {
continue
}
for importPath, req := range missingImports {
imp, ok := imports[importPath]
if !ok {
continue
}
fixes, ok := missingModuleFixes[req]
if !ok {
return nil, fmt.Errorf("no missing module fix for %q (%q)", importPath, req.Mod.Path)
}
srcErr, err := missingModuleForImport(pgf.Tok, m, imp, req, fixes)
if err != nil {
return nil, err
}
diagnostics = append(diagnostics, srcErr)
}
}
}
// Finally, add errors for any unused dependencies.
onlyDiagnostic := len(diagnostics) == 0 && len(unused) == 1
for _, req := range unused {
srcErr, err := unusedDiagnostic(pm.Mapper, req, onlyDiagnostic)
if err != nil {
return nil, err
}
diagnostics = append(diagnostics, srcErr)
}
return diagnostics, nil
}
// unusedDiagnostic returns a source.Diagnostic for an unused require.
func unusedDiagnostic(m *protocol.ColumnMapper, req *modfile.Require, onlyDiagnostic bool) (*source.Diagnostic, error) {
rng, err := rangeFromPositions(m, req.Syntax.Start, req.Syntax.End)
if err != nil {
return nil, err
}
title := fmt.Sprintf("Remove dependency: %s", req.Mod.Path)
cmd, err := command.NewRemoveDependencyCommand(title, command.RemoveDependencyArgs{
URI: protocol.URIFromSpanURI(m.URI),
OnlyDiagnostic: onlyDiagnostic,
ModulePath: req.Mod.Path,
})
if err != nil {
return nil, err
}
return &source.Diagnostic{
URI: m.URI,
Range: rng,
Severity: protocol.SeverityWarning,
Source: source.ModTidyError,
Message: fmt.Sprintf("%s is not used in this module", req.Mod.Path),
SuggestedFixes: []source.SuggestedFix{source.SuggestedFixFromCommand(cmd, protocol.QuickFix)},
}, nil
}
// directnessDiagnostic extracts errors when a dependency is labeled indirect when
// it should be direct and vice versa.
func directnessDiagnostic(m *protocol.ColumnMapper, req *modfile.Require, computeEdits source.DiffFunction) (*source.Diagnostic, error) {
rng, err := rangeFromPositions(m, req.Syntax.Start, req.Syntax.End)
if err != nil {
return nil, err
}
direction := "indirect"
if req.Indirect {
direction = "direct"
// If the dependency should be direct, just highlight the // indirect.
if comments := req.Syntax.Comment(); comments != nil && len(comments.Suffix) > 0 {
end := comments.Suffix[0].Start
end.LineRune += len(comments.Suffix[0].Token)
end.Byte += len([]byte(comments.Suffix[0].Token))
rng, err = rangeFromPositions(m, comments.Suffix[0].Start, end)
if err != nil {
return nil, err
}
}
}
// If the dependency should be indirect, add the // indirect.
edits, err := switchDirectness(req, m, computeEdits)
if err != nil {
return nil, err
}
return &source.Diagnostic{
URI: m.URI,
Range: rng,
Severity: protocol.SeverityWarning,
Source: source.ModTidyError,
Message: fmt.Sprintf("%s should be %s", req.Mod.Path, direction),
SuggestedFixes: []source.SuggestedFix{{
Title: fmt.Sprintf("Change %s to %s", req.Mod.Path, direction),
Edits: map[span.URI][]protocol.TextEdit{
m.URI: edits,
},
ActionKind: protocol.QuickFix,
}},
}, nil
}
func missingModuleDiagnostic(pm *source.ParsedModule, req *modfile.Require) (*source.Diagnostic, error) {
var rng protocol.Range
// Default to the start of the file if there is no module declaration.
if pm.File != nil && pm.File.Module != nil && pm.File.Module.Syntax != nil {
start, end := pm.File.Module.Syntax.Span()
var err error
rng, err = rangeFromPositions(pm.Mapper, start, end)
if err != nil {
return nil, err
}
}
title := fmt.Sprintf("Add %s to your go.mod file", req.Mod.Path)
cmd, err := command.NewAddDependencyCommand(title, command.DependencyArgs{
URI: protocol.URIFromSpanURI(pm.Mapper.URI),
AddRequire: !req.Indirect,
GoCmdArgs: []string{req.Mod.Path + "@" + req.Mod.Version},
})
if err != nil {
return nil, err
}
return &source.Diagnostic{
URI: pm.Mapper.URI,
Range: rng,
Severity: protocol.SeverityError,
Source: source.ModTidyError,
Message: fmt.Sprintf("%s is not in your go.mod file", req.Mod.Path),
SuggestedFixes: []source.SuggestedFix{source.SuggestedFixFromCommand(cmd, protocol.QuickFix)},
}, nil
}
// switchDirectness gets the edits needed to change an indirect dependency to
// direct and vice versa.
func switchDirectness(req *modfile.Require, m *protocol.ColumnMapper, computeEdits source.DiffFunction) ([]protocol.TextEdit, error) {
// We need a private copy of the parsed go.mod file, since we're going to
// modify it.
copied, err := modfile.Parse("", m.Content, nil)
if err != nil {
return nil, err
}
// Change the directness in the matching require statement. To avoid
// reordering the require statements, rewrite all of them.
var requires []*modfile.Require
seenVersions := make(map[string]string)
for _, r := range copied.Require {
if seen := seenVersions[r.Mod.Path]; seen != "" && seen != r.Mod.Version {
// Avoid a panic in SetRequire below, which panics on conflicting
// versions.
return nil, fmt.Errorf("%q has conflicting versions: %q and %q", r.Mod.Path, seen, r.Mod.Version)
}
seenVersions[r.Mod.Path] = r.Mod.Version
if r.Mod.Path == req.Mod.Path {
requires = append(requires, &modfile.Require{
Mod: r.Mod,
Syntax: r.Syntax,
Indirect: !r.Indirect,
})
continue
}
requires = append(requires, r)
}
copied.SetRequire(requires)
newContent, err := copied.Format()
if err != nil {
return nil, err
}
// Calculate the edits to be made due to the change.
edits := computeEdits(string(m.Content), string(newContent))
return source.ToProtocolEdits(m, edits)
}
// missingModuleForImport creates an error for a given import path that comes
// from a missing module.
func missingModuleForImport(file *token.File, m *protocol.ColumnMapper, imp *ast.ImportSpec, req *modfile.Require, fixes []source.SuggestedFix) (*source.Diagnostic, error) {
if req.Syntax == nil {
return nil, fmt.Errorf("no syntax for %v", req)
}
spn, err := span.NewRange(file, imp.Path.Pos(), imp.Path.End()).Span()
if err != nil {
return nil, err
}
rng, err := m.Range(spn)
if err != nil {
return nil, err
}
return &source.Diagnostic{
URI: m.URI,
Range: rng,
Severity: protocol.SeverityError,
Source: source.ModTidyError,
Message: fmt.Sprintf("%s is not in your go.mod file", req.Mod.Path),
SuggestedFixes: fixes,
}, nil
}
func rangeFromPositions(m *protocol.ColumnMapper, s, e modfile.Position) (protocol.Range, error) {
spn, err := spanFromPositions(m, s, e)
if err != nil {
return protocol.Range{}, err
}
return m.Range(spn)
}
func spanFromPositions(m *protocol.ColumnMapper, s, e modfile.Position) (span.Span, error) {
toPoint := func(offset int) (span.Point, error) {
l, c, err := span.ToPosition(m.TokFile, offset)
if err != nil {
return span.Point{}, err
}
return span.NewPoint(l, c, offset), nil
}
start, err := toPoint(s.Byte)
if err != nil {
return span.Span{}, err
}
end, err := toPoint(e.Byte)
if err != nil {
return span.Span{}, err
}
return span.New(m.URI, start, end), nil
}
// parseImports parses the headers of the specified files and returns
// the set of strings that appear in import declarations within
// GoFiles. Errors are ignored.
//
// (We can't simply use ph.m.Metadata.Deps because it contains
// PackageIDs--not import paths--and is based on CompiledGoFiles,
// after cgo processing.)
func parseImports(ctx context.Context, s *snapshot, files []source.FileHandle) map[string]bool {
s.mu.Lock() // peekOrParse requires a locked snapshot (!)
defer s.mu.Unlock()
seen := make(map[string]bool)
for _, file := range files {
f, err := peekOrParse(ctx, s, file, source.ParseHeader)
if err != nil {
continue
}
for _, spec := range f.File.Imports {
path, _ := strconv.Unquote(spec.Path.Value)
seen[path] = true
}
}
return seen
}