blob: 663cf25b184569e149fe6985de1c7fb3b05476a0 [file] [log] [blame]
// 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
import (
"bytes"
"context"
"errors"
"fmt"
"go/ast"
"go/types"
"path/filepath"
"regexp"
"strings"
"sync"
"golang.org/x/mod/module"
"golang.org/x/sync/errgroup"
"golang.org/x/tools/go/ast/astutil"
"golang.org/x/tools/go/packages"
"golang.org/x/tools/gopls/internal/lsp/protocol"
"golang.org/x/tools/gopls/internal/lsp/source"
"golang.org/x/tools/gopls/internal/span"
"golang.org/x/tools/internal/bug"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/event/tag"
"golang.org/x/tools/internal/memoize"
"golang.org/x/tools/internal/packagesinternal"
"golang.org/x/tools/internal/typeparams"
"golang.org/x/tools/internal/typesinternal"
)
// A packageKey identifies a packageHandle in the snapshot.packages map.
type packageKey struct {
mode source.ParseMode
id PackageID
}
type packageHandleKey source.Hash
// A packageHandle is a handle to the future result of type-checking a package.
// The resulting package is obtained from the await() method.
type packageHandle struct {
promise *memoize.Promise // [typeCheckResult]
// m is the metadata associated with the package.
m *source.Metadata
// key is the hashed key for the package.
//
// It includes the all bits of the transitive closure of
// dependencies's sources. This is more than type checking
// really depends on: export data of direct deps should be
// enough. (The key for analysis actions could similarly
// hash only Facts of direct dependencies.)
key packageHandleKey
}
// typeCheckResult contains the result of a call to
// typeCheckImpl, which type-checks a package.
type typeCheckResult struct {
pkg *pkg
err error
}
// buildPackageHandle returns a handle for the future results of
// type-checking the package identified by id in the given mode.
// It assumes that the given ID already has metadata available, so it does not
// attempt to reload missing or invalid metadata. The caller must reload
// metadata if needed.
func (s *snapshot) buildPackageHandle(ctx context.Context, id PackageID, mode source.ParseMode) (*packageHandle, error) {
packageKey := packageKey{id: id, mode: mode}
s.mu.Lock()
entry, hit := s.packages.Get(packageKey)
m := s.meta.metadata[id]
s.mu.Unlock()
if m == nil {
return nil, fmt.Errorf("no metadata for %s", id)
}
if hit {
return entry.(*packageHandle), nil
}
// Begin computing the key by getting the depKeys for all dependencies.
// This requires reading the transitive closure of dependencies' source files.
//
// It is tempting to parallelize the recursion here, but
// without de-duplication of subtasks this would lead to an
// exponential amount of work, and computing the key is
// expensive as it reads all the source files transitively.
// Notably, we don't update the s.packages cache until the
// entire key has been computed.
// TODO(adonovan): use a promise cache to ensure that the key
// for each package is computed by at most one thread, then do
// the recursive key building of dependencies in parallel.
deps := make(map[PackageID]*packageHandle)
var depKey source.Hash // XOR of all unique deps
for _, depID := range m.DepsByPkgPath {
depHandle, err := s.buildPackageHandle(ctx, depID, s.workspaceParseMode(depID))
// Don't use invalid metadata for dependencies if the top-level
// metadata is valid. We only load top-level packages, so if the
// top-level is valid, all of its dependencies should be as well.
if err != nil {
event.Error(ctx, fmt.Sprintf("%s: no dep handle for %s", id, depID), err, source.SnapshotLabels(s)...)
// This check ensures we break out of the slow
// buildPackageHandle recursion quickly when
// context cancelation is detected within GetFile.
if ctx.Err() != nil {
return nil, ctx.Err() // cancelled
}
// One bad dependency should not prevent us from
// checking the entire package. Leave depKeys[i] unset.
continue
}
depKey.XORWith(source.Hash(depHandle.key))
deps[depID] = depHandle
}
// Read both lists of files of this package, in parallel.
//
// goFiles aren't presented to the type checker--nor
// are they included in the key, unsoundly--but their
// syntax trees are available from (*pkg).File(URI).
// TODO(adonovan): consider parsing them on demand?
// The need should be rare.
goFiles, compiledGoFiles, err := readGoFiles(ctx, s, m)
if err != nil {
return nil, err
}
// All the file reading has now been done.
// Create a handle for the result of type checking.
experimentalKey := s.View().Options().ExperimentalPackageCacheKey
phKey := computePackageKey(m.ID, compiledGoFiles, m, depKey, mode, experimentalKey)
promise, release := s.store.Promise(phKey, func(ctx context.Context, arg interface{}) interface{} {
pkg, err := typeCheckImpl(ctx, arg.(*snapshot), goFiles, compiledGoFiles, m, mode, deps)
return typeCheckResult{pkg, err}
})
ph := &packageHandle{
promise: promise,
m: m,
key: phKey,
}
s.mu.Lock()
defer s.mu.Unlock()
// Check that the metadata has not changed
// (which should invalidate this handle).
//
// (In future, handles should form a graph with edges from a
// packageHandle to the handles for parsing its files and the
// handles for type-checking its immediate deps, at which
// point there will be no need to even access s.meta.)
if s.meta.metadata[ph.m.ID] != ph.m {
return nil, fmt.Errorf("stale metadata for %s", ph.m.ID)
}
// Check cache again in case another thread got there first.
if prev, ok := s.packages.Get(packageKey); ok {
prevPH := prev.(*packageHandle)
release()
if prevPH.m != ph.m {
return nil, bug.Errorf("existing package handle does not match for %s", ph.m.ID)
}
return prevPH, nil
}
// Update the map.
s.packages.Set(packageKey, ph, func(_, _ interface{}) { release() })
return ph, nil
}
// readGoFiles reads the content of Metadata.GoFiles and
// Metadata.CompiledGoFiles, in parallel.
func readGoFiles(ctx context.Context, s *snapshot, m *source.Metadata) (goFiles, compiledGoFiles []source.FileHandle, err error) {
var group errgroup.Group
getFileHandles := func(files []span.URI) []source.FileHandle {
fhs := make([]source.FileHandle, len(files))
for i, uri := range files {
i, uri := i, uri
group.Go(func() (err error) {
fhs[i], err = s.GetFile(ctx, uri) // ~25us
return
})
}
return fhs
}
return getFileHandles(m.GoFiles),
getFileHandles(m.CompiledGoFiles),
group.Wait()
}
func (s *snapshot) workspaceParseMode(id PackageID) source.ParseMode {
s.mu.Lock()
defer s.mu.Unlock()
_, ws := s.workspacePackages[id]
if !ws {
return source.ParseExported
}
if s.view.Options().MemoryMode == source.ModeNormal {
return source.ParseFull
}
if s.isActiveLocked(id) {
return source.ParseFull
}
return source.ParseExported
}
// computePackageKey returns a key representing the act of type checking
// a package named id containing the specified files, metadata, and
// combined dependency hash.
func computePackageKey(id PackageID, files []source.FileHandle, m *source.Metadata, depsKey source.Hash, mode source.ParseMode, experimentalKey bool) packageHandleKey {
// TODO(adonovan): opt: no need to materalize the bytes; hash them directly.
// Also, use field separators to avoid spurious collisions.
b := bytes.NewBuffer(nil)
b.WriteString(string(id))
if m.Module != nil {
b.WriteString(m.Module.GoVersion) // go version affects type check errors.
}
if !experimentalKey {
// cfg was used to produce the other hashed inputs (package ID, parsed Go
// files, and deps). It should not otherwise affect the inputs to the type
// checker, so this experiment omits it. This should increase cache hits on
// the daemon as cfg contains the environment and working directory.
hc := hashConfig(m.Config)
b.Write(hc[:])
}
b.WriteByte(byte(mode))
b.Write(depsKey[:])
for _, file := range files {
b.WriteString(file.FileIdentity().String())
}
// Metadata errors are interpreted and memoized on the computed package, so
// we must hash them into the key here.
//
// TODO(rfindley): handle metadata diagnostics independently from
// type-checking diagnostics.
for _, err := range m.Errors {
b.WriteString(err.Msg)
b.WriteString(err.Pos)
b.WriteRune(rune(err.Kind))
}
return packageHandleKey(source.HashOf(b.Bytes()))
}
// hashConfig returns the hash for the *packages.Config.
func hashConfig(config *packages.Config) source.Hash {
// TODO(adonovan): opt: don't materialize the bytes; hash them directly.
// Also, use sound field separators to avoid collisions.
var b bytes.Buffer
// Dir, Mode, Env, BuildFlags are the parts of the config that can change.
b.WriteString(config.Dir)
b.WriteRune(rune(config.Mode))
for _, e := range config.Env {
b.WriteString(e)
}
for _, f := range config.BuildFlags {
b.WriteString(f)
}
return source.HashOf(b.Bytes())
}
// await waits for typeCheckImpl to complete and returns its result.
func (ph *packageHandle) await(ctx context.Context, s *snapshot) (*pkg, error) {
v, err := s.awaitPromise(ctx, ph.promise)
if err != nil {
return nil, err
}
data := v.(typeCheckResult)
return data.pkg, data.err
}
func (ph *packageHandle) CompiledGoFiles() []span.URI {
return ph.m.CompiledGoFiles
}
func (ph *packageHandle) ID() string {
return string(ph.m.ID)
}
func (ph *packageHandle) cached() (*pkg, error) {
v := ph.promise.Cached()
if v == nil {
return nil, fmt.Errorf("no cached type information for %s", ph.m.PkgPath)
}
data := v.(typeCheckResult)
return data.pkg, data.err
}
// typeCheckImpl type checks the parsed source files in compiledGoFiles.
// (The resulting pkg also holds the parsed but not type-checked goFiles.)
// deps holds the future results of type-checking the direct dependencies.
func typeCheckImpl(ctx context.Context, snapshot *snapshot, goFiles, compiledGoFiles []source.FileHandle, m *source.Metadata, mode source.ParseMode, deps map[PackageID]*packageHandle) (*pkg, error) {
// Start type checking of direct dependencies,
// in parallel and asynchronously.
// As the type checker imports each of these
// packages, it will wait for its completion.
var wg sync.WaitGroup
for _, dep := range deps {
wg.Add(1)
go func(dep *packageHandle) {
dep.await(ctx, snapshot) // ignore result
wg.Done()
}(dep)
}
// The 'defer' below is unusual but intentional:
// it is not necessary that each call to dep.check
// complete before type checking begins, as the type
// checker will wait for those it needs. But they do
// need to complete before this function returns and
// the snapshot is possibly destroyed.
defer wg.Wait()
var filter *unexportedFilter
if mode == source.ParseExported {
filter = &unexportedFilter{uses: map[string]bool{}}
}
pkg, err := doTypeCheck(ctx, snapshot, goFiles, compiledGoFiles, m, mode, deps, filter)
if err != nil {
return nil, err
}
if mode == source.ParseExported {
// The AST filtering is a little buggy and may remove things it
// shouldn't. If we only got undeclared name errors, try one more
// time keeping those names.
missing, unexpected := filter.ProcessErrors(pkg.typeErrors)
if len(unexpected) == 0 && len(missing) != 0 {
pkg, err = doTypeCheck(ctx, snapshot, goFiles, compiledGoFiles, m, mode, deps, filter)
if err != nil {
return nil, err
}
missing, unexpected = filter.ProcessErrors(pkg.typeErrors)
}
if len(unexpected) != 0 || len(missing) != 0 {
pkg, err = doTypeCheck(ctx, snapshot, goFiles, compiledGoFiles, m, mode, deps, nil)
if err != nil {
return nil, err
}
}
}
// If this is a replaced module in the workspace, the version is
// meaningless, and we don't want clients to access it.
if m.Module != nil {
version := m.Module.Version
if source.IsWorkspaceModuleVersion(version) {
version = ""
}
pkg.version = &module.Version{
Path: m.Module.Path,
Version: version,
}
}
// We don't care about a package's errors unless we have parsed it in full.
if mode != source.ParseFull {
return pkg, nil
}
for _, e := range m.Errors {
diags, err := goPackagesErrorDiagnostics(snapshot, pkg, e)
if err != nil {
event.Error(ctx, "unable to compute positions for list errors", err, tag.Package.Of(string(pkg.ID())))
continue
}
pkg.diagnostics = append(pkg.diagnostics, diags...)
}
// Our heuristic for whether to show type checking errors is:
// + If any file was 'fixed', don't show type checking errors as we
// can't guarantee that they reference accurate locations in the source.
// + If there is a parse error _in the current file_, suppress type
// errors in that file.
// + Otherwise, show type errors even in the presence of parse errors in
// other package files. go/types attempts to suppress follow-on errors
// due to bad syntax, so on balance type checking errors still provide
// a decent signal/noise ratio as long as the file in question parses.
// Track URIs with parse errors so that we can suppress type errors for these
// files.
unparseable := map[span.URI]bool{}
for _, e := range pkg.parseErrors {
diags, err := parseErrorDiagnostics(snapshot, pkg, e)
if err != nil {
event.Error(ctx, "unable to compute positions for parse errors", err, tag.Package.Of(string(pkg.ID())))
continue
}
for _, diag := range diags {
unparseable[diag.URI] = true
pkg.diagnostics = append(pkg.diagnostics, diag)
}
}
if pkg.hasFixedFiles {
return pkg, nil
}
unexpanded := pkg.typeErrors
pkg.typeErrors = nil
for _, e := range expandErrors(unexpanded, snapshot.View().Options().RelatedInformationSupported) {
diags, err := typeErrorDiagnostics(snapshot, pkg, e)
if err != nil {
event.Error(ctx, "unable to compute positions for type errors", err, tag.Package.Of(string(pkg.ID())))
continue
}
pkg.typeErrors = append(pkg.typeErrors, e.primary)
for _, diag := range diags {
// If the file didn't parse cleanly, it is highly likely that type
// checking errors will be confusing or redundant. But otherwise, type
// checking usually provides a good enough signal to include.
if !unparseable[diag.URI] {
pkg.diagnostics = append(pkg.diagnostics, diag)
}
}
}
depsErrors, err := snapshot.depsErrors(ctx, pkg)
if err != nil {
return nil, err
}
pkg.diagnostics = append(pkg.diagnostics, depsErrors...)
return pkg, nil
}
var goVersionRx = regexp.MustCompile(`^go([1-9][0-9]*)\.(0|[1-9][0-9]*)$`)
func doTypeCheck(ctx context.Context, snapshot *snapshot, goFiles, compiledGoFiles []source.FileHandle, m *source.Metadata, mode source.ParseMode, deps map[PackageID]*packageHandle, astFilter *unexportedFilter) (*pkg, error) {
ctx, done := event.Start(ctx, "cache.typeCheck", tag.Package.Of(string(m.ID)))
defer done()
pkg := &pkg{
m: m,
mode: mode,
fset: snapshot.FileSet(), // must match parse call below (snapshot.ParseGo for now)
deps: make(map[PackageID]*pkg),
types: types.NewPackage(string(m.PkgPath), string(m.Name)),
typesInfo: &types.Info{
Types: make(map[ast.Expr]types.TypeAndValue),
Defs: make(map[*ast.Ident]types.Object),
Uses: make(map[*ast.Ident]types.Object),
Implicits: make(map[ast.Node]types.Object),
Selections: make(map[*ast.SelectorExpr]*types.Selection),
Scopes: make(map[ast.Node]*types.Scope),
},
}
typeparams.InitInstanceInfo(pkg.typesInfo)
// In the presence of line directives, we may need to report errors in
// non-compiled Go files, so we need to register them on the package.
// However, we only need to really parse them in ParseFull mode, when
// the user might actually be looking at the file.
goMode := source.ParseFull
if mode != source.ParseFull {
goMode = source.ParseHeader
}
// Parse the GoFiles. (These aren't presented to the type
// checker but are part of the returned pkg.)
// TODO(adonovan): opt: parallelize parsing.
for _, fh := range goFiles {
pgf, err := snapshot.ParseGo(ctx, fh, goMode)
if err != nil {
return nil, err
}
pkg.goFiles = append(pkg.goFiles, pgf)
}
// Parse the CompiledGoFiles: those seen by the compiler/typechecker.
if err := parseCompiledGoFiles(ctx, compiledGoFiles, snapshot, mode, pkg, astFilter); err != nil {
return nil, err
}
// Use the default type information for the unsafe package.
if m.PkgPath == "unsafe" {
// Don't type check Unsafe: it's unnecessary, and doing so exposes a data
// race to Unsafe.completed.
pkg.types = types.Unsafe
return pkg, nil
}
if len(m.CompiledGoFiles) == 0 {
// No files most likely means go/packages failed. Try to attach error
// messages to the file as much as possible.
var found bool
for _, e := range m.Errors {
srcDiags, err := goPackagesErrorDiagnostics(snapshot, pkg, e)
if err != nil {
continue
}
found = true
pkg.diagnostics = append(pkg.diagnostics, srcDiags...)
}
if found {
return pkg, nil
}
return nil, fmt.Errorf("no parsed files for package %s, expected: %v, errors: %v", pkg.m.PkgPath, pkg.compiledGoFiles, m.Errors)
}
cfg := &types.Config{
Error: func(e error) {
pkg.typeErrors = append(pkg.typeErrors, e.(types.Error))
},
Importer: importerFunc(func(path string) (*types.Package, error) {
// While all of the import errors could be reported
// based on the metadata before we start type checking,
// reporting them via types.Importer places the errors
// at the correct source location.
id, ok := pkg.m.DepsByImpPath[ImportPath(path)]
if !ok {
// If the import declaration is broken,
// go list may fail to report metadata about it.
// See TestFixImportDecl for an example.
return nil, fmt.Errorf("missing metadata for import of %q", path)
}
dep, ok := deps[id] // id may be ""
if !ok {
return nil, snapshot.missingPkgError(path)
}
if !source.IsValidImport(m.PkgPath, dep.m.PkgPath) {
return nil, fmt.Errorf("invalid use of internal package %s", path)
}
depPkg, err := dep.await(ctx, snapshot)
if err != nil {
return nil, err
}
pkg.deps[depPkg.m.ID] = depPkg
return depPkg.types, nil
}),
}
if pkg.m.Module != nil && pkg.m.Module.GoVersion != "" {
goVersion := "go" + pkg.m.Module.GoVersion
// types.NewChecker panics if GoVersion is invalid. An unparsable mod
// file should probably stop us before we get here, but double check
// just in case.
if goVersionRx.MatchString(goVersion) {
typesinternal.SetGoVersion(cfg, goVersion)
}
}
if mode != source.ParseFull {
cfg.DisableUnusedImportCheck = true
cfg.IgnoreFuncBodies = true
}
// We want to type check cgo code if go/types supports it.
// We passed typecheckCgo to go/packages when we Loaded.
typesinternal.SetUsesCgo(cfg)
check := types.NewChecker(cfg, pkg.fset, pkg.types, pkg.typesInfo)
var files []*ast.File
for _, cgf := range pkg.compiledGoFiles {
files = append(files, cgf.File)
}
// Type checking errors are handled via the config, so ignore them here.
_ = check.Files(files) // 50us-15ms, depending on size of package
// If the context was cancelled, we may have returned a ton of transient
// errors to the type checker. Swallow them.
if ctx.Err() != nil {
return nil, ctx.Err()
}
return pkg, nil
}
func parseCompiledGoFiles(ctx context.Context, compiledGoFiles []source.FileHandle, snapshot *snapshot, mode source.ParseMode, pkg *pkg, astFilter *unexportedFilter) error {
// TODO(adonovan): opt: parallelize this loop, which takes 1-25ms.
for _, fh := range compiledGoFiles {
var pgf *source.ParsedGoFile
var err error
// Only parse Full through the cache -- we need to own Exported ASTs
// to prune them.
if mode == source.ParseFull {
pgf, err = snapshot.ParseGo(ctx, fh, mode)
} else {
pgf, err = parseGoImpl(ctx, pkg.fset, fh, mode) // ~20us/KB
}
if err != nil {
return err
}
pkg.compiledGoFiles = append(pkg.compiledGoFiles, pgf)
if pgf.ParseErr != nil {
pkg.parseErrors = append(pkg.parseErrors, pgf.ParseErr)
}
// If we have fixed parse errors in any of the files, we should hide type
// errors, as they may be completely nonsensical.
pkg.hasFixedFiles = pkg.hasFixedFiles || pgf.Fixed
}
// Optionally remove parts that don't affect the exported API.
if mode == source.ParseExported {
if astFilter != nil {
// aggressive pruning based on reachability
var files []*ast.File
for _, cgf := range pkg.compiledGoFiles {
files = append(files, cgf.File)
}
astFilter.Filter(files)
} else {
// simple trimming of function bodies
for _, cgf := range pkg.compiledGoFiles {
trimAST(cgf.File)
}
}
}
return nil
}
func (s *snapshot) depsErrors(ctx context.Context, pkg *pkg) ([]*source.Diagnostic, error) {
// Select packages that can't be found, and were imported in non-workspace packages.
// Workspace packages already show their own errors.
var relevantErrors []*packagesinternal.PackageError
for _, depsError := range pkg.m.DepsErrors {
// Up to Go 1.15, the missing package was included in the stack, which
// was presumably a bug. We want the next one up.
directImporterIdx := len(depsError.ImportStack) - 1
if s.view.goversion < 15 {
directImporterIdx = len(depsError.ImportStack) - 2
}
if directImporterIdx < 0 {
continue
}
directImporter := depsError.ImportStack[directImporterIdx]
if s.isWorkspacePackage(PackageID(directImporter)) {
continue
}
relevantErrors = append(relevantErrors, depsError)
}
// Don't build the import index for nothing.
if len(relevantErrors) == 0 {
return nil, nil
}
// Build an index of all imports in the package.
type fileImport struct {
cgf *source.ParsedGoFile
imp *ast.ImportSpec
}
allImports := map[string][]fileImport{}
for _, cgf := range pkg.compiledGoFiles {
// TODO(adonovan): modify Imports() to accept a single token.File (cgf.Tok).
for _, group := range astutil.Imports(s.FileSet(), cgf.File) {
for _, imp := range group {
if imp.Path == nil {
continue
}
path := strings.Trim(imp.Path.Value, `"`)
allImports[path] = append(allImports[path], fileImport{cgf, imp})
}
}
}
// Apply a diagnostic to any import involved in the error, stopping once
// we reach the workspace.
var errors []*source.Diagnostic
for _, depErr := range relevantErrors {
for i := len(depErr.ImportStack) - 1; i >= 0; i-- {
item := depErr.ImportStack[i]
if s.isWorkspacePackage(PackageID(item)) {
break
}
for _, imp := range allImports[item] {
rng, err := source.NewMappedRange(imp.cgf.Tok, imp.cgf.Mapper, imp.imp.Pos(), imp.imp.End()).Range()
if err != nil {
return nil, err
}
fixes, err := goGetQuickFixes(s, imp.cgf.URI, item)
if err != nil {
return nil, err
}
errors = append(errors, &source.Diagnostic{
URI: imp.cgf.URI,
Range: rng,
Severity: protocol.SeverityError,
Source: source.TypeError,
Message: fmt.Sprintf("error while importing %v: %v", item, depErr.Err),
SuggestedFixes: fixes,
})
}
}
}
if len(pkg.compiledGoFiles) == 0 {
return errors, nil
}
mod := s.GoModForFile(pkg.compiledGoFiles[0].URI)
if mod == "" {
return errors, nil
}
fh, err := s.GetFile(ctx, mod)
if err != nil {
return nil, err
}
pm, err := s.ParseMod(ctx, fh)
if err != nil {
return nil, err
}
// Add a diagnostic to the module that contained the lowest-level import of
// the missing package.
for _, depErr := range relevantErrors {
for i := len(depErr.ImportStack) - 1; i >= 0; i-- {
item := depErr.ImportStack[i]
m := s.getMetadata(PackageID(item))
if m == nil || m.Module == nil {
continue
}
modVer := module.Version{Path: m.Module.Path, Version: m.Module.Version}
reference := findModuleReference(pm.File, modVer)
if reference == nil {
continue
}
rng, err := pm.Mapper.OffsetRange(reference.Start.Byte, reference.End.Byte)
if err != nil {
return nil, err
}
fixes, err := goGetQuickFixes(s, pm.URI, item)
if err != nil {
return nil, err
}
errors = append(errors, &source.Diagnostic{
URI: pm.URI,
Range: rng,
Severity: protocol.SeverityError,
Source: source.TypeError,
Message: fmt.Sprintf("error while importing %v: %v", item, depErr.Err),
SuggestedFixes: fixes,
})
break
}
}
return errors, nil
}
// missingPkgError returns an error message for a missing package that varies
// based on the user's workspace mode.
func (s *snapshot) missingPkgError(pkgPath string) error {
var b strings.Builder
if s.workspaceMode()&moduleMode == 0 {
gorootSrcPkg := filepath.FromSlash(filepath.Join(s.view.goroot, "src", pkgPath))
fmt.Fprintf(&b, "cannot find package %q in any of \n\t%s (from $GOROOT)", pkgPath, gorootSrcPkg)
for _, gopath := range filepath.SplitList(s.view.gopath) {
gopathSrcPkg := filepath.FromSlash(filepath.Join(gopath, "src", pkgPath))
fmt.Fprintf(&b, "\n\t%s (from $GOPATH)", gopathSrcPkg)
}
} else {
fmt.Fprintf(&b, "no required module provides package %q", pkgPath)
if err := s.getInitializationError(); err != nil {
fmt.Fprintf(&b, "\n(workspace configuration error: %s)", err.MainError)
}
}
return errors.New(b.String())
}
type extendedError struct {
primary types.Error
secondaries []types.Error
}
func (e extendedError) Error() string {
return e.primary.Error()
}
// expandErrors duplicates "secondary" errors by mapping them to their main
// error. Some errors returned by the type checker are followed by secondary
// errors which give more information about the error. These are errors in
// their own right, and they are marked by starting with \t. For instance, when
// there is a multiply-defined function, the secondary error points back to the
// definition first noticed.
//
// This function associates the secondary error with its primary error, which can
// then be used as RelatedInformation when the error becomes a diagnostic.
//
// If supportsRelatedInformation is false, the secondary is instead embedded as
// additional context in the primary error.
func expandErrors(errs []types.Error, supportsRelatedInformation bool) []extendedError {
var result []extendedError
for i := 0; i < len(errs); {
original := extendedError{
primary: errs[i],
}
for i++; i < len(errs); i++ {
spl := errs[i]
if len(spl.Msg) == 0 || spl.Msg[0] != '\t' {
break
}
spl.Msg = spl.Msg[1:]
original.secondaries = append(original.secondaries, spl)
}
// Clone the error to all its related locations -- VS Code, at least,
// doesn't do it for us.
result = append(result, original)
for i, mainSecondary := range original.secondaries {
// Create the new primary error, with a tweaked message, in the
// secondary's location. We need to start from the secondary to
// capture its unexported location fields.
relocatedSecondary := mainSecondary
if supportsRelatedInformation {
relocatedSecondary.Msg = fmt.Sprintf("%v (see details)", original.primary.Msg)
} else {
relocatedSecondary.Msg = fmt.Sprintf("%v (this error: %v)", original.primary.Msg, mainSecondary.Msg)
}
relocatedSecondary.Soft = original.primary.Soft
// Copy over the secondary errors, noting the location of the
// current error we're cloning.
clonedError := extendedError{primary: relocatedSecondary, secondaries: []types.Error{original.primary}}
for j, secondary := range original.secondaries {
if i == j {
secondary.Msg += " (this error)"
}
clonedError.secondaries = append(clonedError.secondaries, secondary)
}
result = append(result, clonedError)
}
}
return result
}
// An importFunc is an implementation of the single-method
// types.Importer interface based on a function value.
type importerFunc func(path string) (*types.Package, error)
func (f importerFunc) Import(path string) (*types.Package, error) { return f(path) }