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// 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 cache
// This file defines routines to convert diagnostics from go list, go
// get, go/packages, parsing, type checking, and analysis into
// source.Diagnostic form, and suggesting quick fixes.
import (
"context"
"fmt"
"go/parser"
"go/scanner"
"go/token"
"go/types"
"log"
"regexp"
"strconv"
"strings"
"golang.org/x/tools/go/packages"
"golang.org/x/tools/gopls/internal/lsp/command"
"golang.org/x/tools/gopls/internal/lsp/protocol"
"golang.org/x/tools/gopls/internal/lsp/safetoken"
"golang.org/x/tools/gopls/internal/lsp/source"
"golang.org/x/tools/gopls/internal/span"
"golang.org/x/tools/internal/analysisinternal"
"golang.org/x/tools/internal/bug"
"golang.org/x/tools/internal/typesinternal"
)
// goPackagesErrorDiagnostics translates the given go/packages Error into a
// diagnostic, using the provided metadata and filesource.
//
// The slice of diagnostics may be empty.
func goPackagesErrorDiagnostics(ctx context.Context, e packages.Error, m *source.Metadata, fs source.FileSource) ([]*source.Diagnostic, error) {
if diag, err := parseGoListImportCycleError(ctx, e, m, fs); err != nil {
return nil, err
} else if diag != nil {
return []*source.Diagnostic{diag}, nil
}
var spn span.Span
if e.Pos == "" {
spn = parseGoListError(e.Msg, m.LoadDir)
// We may not have been able to parse a valid span. Apply the errors to all files.
if _, err := spanToRange(ctx, fs, spn); err != nil {
var diags []*source.Diagnostic
for _, uri := range m.CompiledGoFiles {
diags = append(diags, &source.Diagnostic{
URI: uri,
Severity: protocol.SeverityError,
Source: source.ListError,
Message: e.Msg,
})
}
return diags, nil
}
} else {
spn = span.ParseInDir(e.Pos, m.LoadDir)
}
// TODO(rfindley): in some cases the go command outputs invalid spans, for
// example (from TestGoListErrors):
//
// package a
// import
//
// In this case, the go command will complain about a.go:2:8, which is after
// the trailing newline but still considered to be on the second line, most
// likely because *token.File lacks information about newline termination.
//
// We could do better here by handling that case.
rng, err := spanToRange(ctx, fs, spn)
if err != nil {
return nil, err
}
return []*source.Diagnostic{{
URI: spn.URI(),
Range: rng,
Severity: protocol.SeverityError,
Source: source.ListError,
Message: e.Msg,
}}, nil
}
func parseErrorDiagnostics(pkg *syntaxPackage, errList scanner.ErrorList) ([]*source.Diagnostic, error) {
// The first parser error is likely the root cause of the problem.
if errList.Len() <= 0 {
return nil, fmt.Errorf("no errors in %v", errList)
}
e := errList[0]
pgf, err := pkg.File(span.URIFromPath(e.Pos.Filename))
if err != nil {
return nil, err
}
rng, err := pgf.Mapper.OffsetRange(e.Pos.Offset, e.Pos.Offset)
if err != nil {
return nil, err
}
return []*source.Diagnostic{{
URI: pgf.URI,
Range: rng,
Severity: protocol.SeverityError,
Source: source.ParseError,
Message: e.Msg,
}}, nil
}
var importErrorRe = regexp.MustCompile(`could not import ([^\s]+)`)
var unsupportedFeatureRe = regexp.MustCompile(`.*require.* go(\d+\.\d+) or later`)
func typeErrorDiagnostics(moduleMode bool, linkTarget string, pkg *syntaxPackage, e extendedError) ([]*source.Diagnostic, error) {
code, loc, err := typeErrorData(pkg, e.primary)
if err != nil {
return nil, err
}
diag := &source.Diagnostic{
URI: loc.URI.SpanURI(),
Range: loc.Range,
Severity: protocol.SeverityError,
Source: source.TypeError,
Message: e.primary.Msg,
}
if code != 0 {
diag.Code = code.String()
diag.CodeHref = typesCodeHref(linkTarget, code)
}
switch code {
case typesinternal.UnusedVar, typesinternal.UnusedImport:
diag.Tags = append(diag.Tags, protocol.Unnecessary)
}
for _, secondary := range e.secondaries {
_, secondaryLoc, err := typeErrorData(pkg, secondary)
if err != nil {
// We may not be able to compute type error data in scenarios where the
// secondary position is outside of the current package. In this case, we
// don't want to ignore the diagnostic entirely.
//
// See golang/go#59005 for an example where gopls was missing diagnostics
// due to returning an error here.
continue
}
diag.Related = append(diag.Related, protocol.DiagnosticRelatedInformation{
Location: secondaryLoc,
Message: secondary.Msg,
})
}
if match := importErrorRe.FindStringSubmatch(e.primary.Msg); match != nil {
diag.SuggestedFixes, err = goGetQuickFixes(moduleMode, loc.URI.SpanURI(), match[1])
if err != nil {
return nil, err
}
}
if match := unsupportedFeatureRe.FindStringSubmatch(e.primary.Msg); match != nil {
diag.SuggestedFixes, err = editGoDirectiveQuickFix(moduleMode, loc.URI.SpanURI(), match[1])
if err != nil {
return nil, err
}
}
return []*source.Diagnostic{diag}, nil
}
func goGetQuickFixes(moduleMode bool, uri span.URI, pkg string) ([]source.SuggestedFix, error) {
// Go get only supports module mode for now.
if !moduleMode {
return nil, nil
}
title := fmt.Sprintf("go get package %v", pkg)
cmd, err := command.NewGoGetPackageCommand(title, command.GoGetPackageArgs{
URI: protocol.URIFromSpanURI(uri),
AddRequire: true,
Pkg: pkg,
})
if err != nil {
return nil, err
}
return []source.SuggestedFix{source.SuggestedFixFromCommand(cmd, protocol.QuickFix)}, nil
}
func editGoDirectiveQuickFix(moduleMode bool, uri span.URI, version string) ([]source.SuggestedFix, error) {
// Go mod edit only supports module mode.
if !moduleMode {
return nil, nil
}
title := fmt.Sprintf("go mod edit -go=%s", version)
cmd, err := command.NewEditGoDirectiveCommand(title, command.EditGoDirectiveArgs{
URI: protocol.URIFromSpanURI(uri),
Version: version,
})
if err != nil {
return nil, err
}
return []source.SuggestedFix{source.SuggestedFixFromCommand(cmd, protocol.QuickFix)}, nil
}
// encodeDiagnostics gob-encodes the given diagnostics.
func encodeDiagnostics(srcDiags []*source.Diagnostic) []byte {
var gobDiags []gobDiagnostic
for _, srcDiag := range srcDiags {
var gobFixes []gobSuggestedFix
for _, srcFix := range srcDiag.SuggestedFixes {
gobFix := gobSuggestedFix{
Message: srcFix.Title,
ActionKind: srcFix.ActionKind,
}
for uri, srcEdits := range srcFix.Edits {
for _, srcEdit := range srcEdits {
gobFix.TextEdits = append(gobFix.TextEdits, gobTextEdit{
Location: protocol.Location{
URI: protocol.URIFromSpanURI(uri),
Range: srcEdit.Range,
},
NewText: []byte(srcEdit.NewText),
})
}
}
if srcCmd := srcFix.Command; srcCmd != nil {
gobFix.Command = &gobCommand{
Title: srcCmd.Title,
Command: srcCmd.Command,
Arguments: srcCmd.Arguments,
}
}
gobFixes = append(gobFixes, gobFix)
}
var gobRelated []gobRelatedInformation
for _, srcRel := range srcDiag.Related {
gobRel := gobRelatedInformation(srcRel)
gobRelated = append(gobRelated, gobRel)
}
gobDiag := gobDiagnostic{
Location: protocol.Location{
URI: protocol.URIFromSpanURI(srcDiag.URI),
Range: srcDiag.Range,
},
Severity: srcDiag.Severity,
Code: srcDiag.Code,
CodeHref: srcDiag.CodeHref,
Source: string(srcDiag.Source),
Message: srcDiag.Message,
SuggestedFixes: gobFixes,
Related: gobRelated,
Tags: srcDiag.Tags,
}
gobDiags = append(gobDiags, gobDiag)
}
return mustJSONEncode(gobDiags)
}
// decodeDiagnostics decodes the given gob-encoded diagnostics.
func decodeDiagnostics(data []byte) []*source.Diagnostic {
var gobDiags []gobDiagnostic
mustJSONDecode(data, &gobDiags)
var srcDiags []*source.Diagnostic
for _, gobDiag := range gobDiags {
var srcFixes []source.SuggestedFix
for _, gobFix := range gobDiag.SuggestedFixes {
srcFix := source.SuggestedFix{
Title: gobFix.Message,
ActionKind: gobFix.ActionKind,
}
for _, gobEdit := range gobFix.TextEdits {
if srcFix.Edits == nil {
srcFix.Edits = make(map[span.URI][]protocol.TextEdit)
}
srcEdit := protocol.TextEdit{
Range: gobEdit.Location.Range,
NewText: string(gobEdit.NewText),
}
uri := gobEdit.Location.URI.SpanURI()
srcFix.Edits[uri] = append(srcFix.Edits[uri], srcEdit)
}
if gobCmd := gobFix.Command; gobCmd != nil {
srcFix.Command = &protocol.Command{
Title: gobCmd.Title,
Command: gobCmd.Command,
Arguments: gobCmd.Arguments,
}
}
srcFixes = append(srcFixes, srcFix)
}
var srcRelated []protocol.DiagnosticRelatedInformation
for _, gobRel := range gobDiag.Related {
srcRel := protocol.DiagnosticRelatedInformation(gobRel)
srcRelated = append(srcRelated, srcRel)
}
srcDiag := &source.Diagnostic{
URI: gobDiag.Location.URI.SpanURI(),
Range: gobDiag.Location.Range,
Severity: gobDiag.Severity,
Code: gobDiag.Code,
CodeHref: gobDiag.CodeHref,
Source: source.AnalyzerErrorKind(gobDiag.Source),
Message: gobDiag.Message,
Tags: gobDiag.Tags,
Related: srcRelated,
SuggestedFixes: srcFixes,
}
srcDiags = append(srcDiags, srcDiag)
}
return srcDiags
}
// toSourceDiagnostic converts a gobDiagnostic to "source" form.
func toSourceDiagnostic(srcAnalyzer *source.Analyzer, gobDiag *gobDiagnostic) *source.Diagnostic {
var related []protocol.DiagnosticRelatedInformation
for _, gobRelated := range gobDiag.Related {
related = append(related, protocol.DiagnosticRelatedInformation(gobRelated))
}
kinds := srcAnalyzer.ActionKind
if len(srcAnalyzer.ActionKind) == 0 {
kinds = append(kinds, protocol.QuickFix)
}
fixes := suggestedAnalysisFixes(gobDiag, kinds)
if srcAnalyzer.Fix != "" {
cmd, err := command.NewApplyFixCommand(gobDiag.Message, command.ApplyFixArgs{
URI: gobDiag.Location.URI,
Range: gobDiag.Location.Range,
Fix: srcAnalyzer.Fix,
})
if err != nil {
// JSON marshalling of these argument values cannot fail.
log.Fatalf("internal error in NewApplyFixCommand: %v", err)
}
for _, kind := range kinds {
fixes = append(fixes, source.SuggestedFixFromCommand(cmd, kind))
}
}
severity := srcAnalyzer.Severity
if severity == 0 {
severity = protocol.SeverityWarning
}
diag := &source.Diagnostic{
URI: gobDiag.Location.URI.SpanURI(),
Range: gobDiag.Location.Range,
Severity: severity,
Source: source.AnalyzerErrorKind(gobDiag.Source),
Message: gobDiag.Message,
Related: related,
SuggestedFixes: fixes,
}
// If the fixes only delete code, assume that the diagnostic is reporting dead code.
if onlyDeletions(fixes) {
diag.Tags = []protocol.DiagnosticTag{protocol.Unnecessary}
}
return diag
}
// onlyDeletions returns true if all of the suggested fixes are deletions.
func onlyDeletions(fixes []source.SuggestedFix) bool {
for _, fix := range fixes {
if fix.Command != nil {
return false
}
for _, edits := range fix.Edits {
for _, edit := range edits {
if edit.NewText != "" {
return false
}
if protocol.ComparePosition(edit.Range.Start, edit.Range.End) == 0 {
return false
}
}
}
}
return len(fixes) > 0
}
func typesCodeHref(linkTarget string, code typesinternal.ErrorCode) string {
return source.BuildLink(linkTarget, "golang.org/x/tools/internal/typesinternal", code.String())
}
func suggestedAnalysisFixes(diag *gobDiagnostic, kinds []protocol.CodeActionKind) []source.SuggestedFix {
var fixes []source.SuggestedFix
for _, fix := range diag.SuggestedFixes {
edits := make(map[span.URI][]protocol.TextEdit)
for _, e := range fix.TextEdits {
uri := span.URI(e.Location.URI)
edits[uri] = append(edits[uri], protocol.TextEdit{
Range: e.Location.Range,
NewText: string(e.NewText),
})
}
for _, kind := range kinds {
fixes = append(fixes, source.SuggestedFix{
Title: fix.Message,
Edits: edits,
ActionKind: kind,
})
}
}
return fixes
}
func typeErrorData(pkg *syntaxPackage, terr types.Error) (typesinternal.ErrorCode, protocol.Location, error) {
ecode, start, end, ok := typesinternal.ReadGo116ErrorData(terr)
if !ok {
start, end = terr.Pos, terr.Pos
ecode = 0
}
// go/types may return invalid positions in some cases, such as
// in errors on tokens missing from the syntax tree.
if !start.IsValid() {
return 0, protocol.Location{}, fmt.Errorf("type error (%q, code %d, go116=%t) without position", terr.Msg, ecode, ok)
}
// go/types errors retain their FileSet.
// Sanity-check that we're using the right one.
fset := pkg.fset
if fset != terr.Fset {
return 0, protocol.Location{}, bug.Errorf("wrong FileSet for type error")
}
posn := safetoken.StartPosition(fset, start)
if !posn.IsValid() {
return 0, protocol.Location{}, fmt.Errorf("position %d of type error %q (code %q) not found in FileSet", start, start, terr)
}
pgf, err := pkg.File(span.URIFromPath(posn.Filename))
if err != nil {
return 0, protocol.Location{}, err
}
if !end.IsValid() || end == start {
end = analysisinternal.TypeErrorEndPos(fset, pgf.Src, start)
}
loc, err := pgf.Mapper.PosLocation(pgf.Tok, start, end)
return ecode, loc, err
}
// spanToRange converts a span.Span to a protocol.Range, by mapping content
// contained in the provided FileSource.
func spanToRange(ctx context.Context, fs source.FileSource, spn span.Span) (protocol.Range, error) {
uri := spn.URI()
fh, err := fs.ReadFile(ctx, uri)
if err != nil {
return protocol.Range{}, err
}
content, err := fh.Content()
if err != nil {
return protocol.Range{}, err
}
mapper := protocol.NewMapper(uri, content)
return mapper.SpanRange(spn)
}
// parseGoListError attempts to parse a standard `go list` error message
// by stripping off the trailing error message.
//
// It works only on errors whose message is prefixed by colon,
// followed by a space (": "). For example:
//
// attributes.go:13:1: expected 'package', found 'type'
func parseGoListError(input, wd string) span.Span {
input = strings.TrimSpace(input)
msgIndex := strings.Index(input, ": ")
if msgIndex < 0 {
return span.Parse(input)
}
return span.ParseInDir(input[:msgIndex], wd)
}
// parseGoListImportCycleError attempts to parse the given go/packages error as
// an import cycle, returning a diagnostic if successful.
//
// If the error is not detected as an import cycle error, it returns nil, nil.
func parseGoListImportCycleError(ctx context.Context, e packages.Error, m *source.Metadata, fs source.FileSource) (*source.Diagnostic, error) {
re := regexp.MustCompile(`(.*): import stack: \[(.+)\]`)
matches := re.FindStringSubmatch(strings.TrimSpace(e.Msg))
if len(matches) < 3 {
return nil, nil
}
msg := matches[1]
importList := strings.Split(matches[2], " ")
// Since the error is relative to the current package. The import that is causing
// the import cycle error is the second one in the list.
if len(importList) < 2 {
return nil, nil
}
// Imports have quotation marks around them.
circImp := strconv.Quote(importList[1])
for _, uri := range m.CompiledGoFiles {
pgf, err := parseGoURI(ctx, fs, uri, source.ParseHeader)
if err != nil {
return nil, err
}
// Search file imports for the import that is causing the import cycle.
for _, imp := range pgf.File.Imports {
if imp.Path.Value == circImp {
rng, err := pgf.NodeMappedRange(imp)
if err != nil {
return nil, nil
}
return &source.Diagnostic{
URI: pgf.URI,
Range: rng.Range(),
Severity: protocol.SeverityError,
Source: source.ListError,
Message: msg,
}, nil
}
}
}
return nil, nil
}
// parseGoURI is a helper to parse the Go file at the given URI from the file
// source fs. The resulting syntax and token.File belong to an ephemeral,
// encapsulated FileSet, so this file stands only on its own: it's not suitable
// to use in a list of file of a package, for example.
//
// It returns an error if the file could not be read.
func parseGoURI(ctx context.Context, fs source.FileSource, uri span.URI, mode parser.Mode) (*source.ParsedGoFile, error) {
fh, err := fs.ReadFile(ctx, uri)
if err != nil {
return nil, err
}
return parseGoImpl(ctx, token.NewFileSet(), fh, mode)
}
// parseModURI is a helper to parse the Mod file at the given URI from the file
// source fs.
//
// It returns an error if the file could not be read.
func parseModURI(ctx context.Context, fs source.FileSource, uri span.URI) (*source.ParsedModule, error) {
fh, err := fs.ReadFile(ctx, uri)
if err != nil {
return nil, err
}
return parseModImpl(ctx, fh)
}