TUN-9016: update go to 1.24

## Summary

Update several moving parts of cloudflared build system:

* use goboring 1.24.2 in cfsetup
* update linter and fix lint issues
* update packages namely **quic-go and net**
* install script for macos
* update docker files to use go 1.24.1
* remove usage of cloudflare-go
* pin golang linter

Closes TUN-9016

vendor/golang.org/x/tools/internal/modindex/directories.go

@@ -0,0 +1,135 @@
+// Copyright 2024 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 modindex
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"regexp"
+	"slices"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/mod/semver"
+	"golang.org/x/tools/internal/gopathwalk"
+)
+
+type directory struct {
+	path       Relpath
+	importPath string
+	version    string // semantic version
+	syms       []symbol
+}
+
+// filterDirs groups the directories by import path,
+// sorting the ones with the same import path by semantic version,
+// most recent first.
+func byImportPath(dirs []Relpath) (map[string][]*directory, error) {
+	ans := make(map[string][]*directory) // key is import path
+	for _, d := range dirs {
+		ip, sv, err := DirToImportPathVersion(d)
+		if err != nil {
+			return nil, err
+		}
+		ans[ip] = append(ans[ip], &directory{
+			path:       d,
+			importPath: ip,
+			version:    sv,
+		})
+	}
+	for k, v := range ans {
+		semanticSort(v)
+		ans[k] = v
+	}
+	return ans, nil
+}
+
+// sort the directories by semantic version, latest first
+func semanticSort(v []*directory) {
+	slices.SortFunc(v, func(l, r *directory) int {
+		if n := semver.Compare(l.version, r.version); n != 0 {
+			return -n // latest first
+		}
+		return strings.Compare(string(l.path), string(r.path))
+	})
+}
+
+// modCacheRegexp splits a relpathpath into module, module version, and package.
+var modCacheRegexp = regexp.MustCompile(`(.*)@([^/\\]*)(.*)`)
+
+// DirToImportPathVersion computes import path and semantic version
+func DirToImportPathVersion(dir Relpath) (string, string, error) {
+	m := modCacheRegexp.FindStringSubmatch(string(dir))
+	// m[1] is the module path
+	// m[2] is the version major.minor.patch(-<pre release identifier)
+	// m[3] is the rest of the package path
+	if len(m) != 4 {
+		return "", "", fmt.Errorf("bad dir %s", dir)
+	}
+	if !semver.IsValid(m[2]) {
+		return "", "", fmt.Errorf("bad semantic version %s", m[2])
+	}
+	// ToSlash is required for Windows.
+	return filepath.ToSlash(m[1] + m[3]), m[2], nil
+}
+
+// a region controls what directories to look at, for
+// updating the index incrementally, and for testing that.
+// (for testing one builds an index as of A, incrementally
+// updates it to B, and compares the result to an index build
+// as of B.)
+type region struct {
+	onlyAfter, onlyBefore time.Time
+	sync.Mutex
+	ans []Relpath
+}
+
+func findDirs(root string, onlyAfter, onlyBefore time.Time) []Relpath {
+	roots := []gopathwalk.Root{{Path: root, Type: gopathwalk.RootModuleCache}}
+	// TODO(PJW): adjust concurrency
+	opts := gopathwalk.Options{ModulesEnabled: true, Concurrency: 1 /* ,Logf: log.Printf*/}
+	betw := &region{
+		onlyAfter:  onlyAfter,
+		onlyBefore: onlyBefore,
+	}
+	gopathwalk.WalkSkip(roots, betw.addDir, betw.skipDir, opts)
+	return betw.ans
+}
+
+func (r *region) addDir(rt gopathwalk.Root, dir string) {
+	// do we need to check times?
+	r.Lock()
+	defer r.Unlock()
+	x := filepath.ToSlash(string(toRelpath(Abspath(rt.Path), dir)))
+	r.ans = append(r.ans, toRelpath(Abspath(rt.Path), x))
+}
+
+func (r *region) skipDir(_ gopathwalk.Root, dir string) bool {
+	// The cache directory is already ignored in gopathwalk\
+	if filepath.Base(dir) == "internal" {
+		return true
+	}
+	if strings.Contains(dir, "toolchain@") {
+		return true
+	}
+	// don't look inside @ directories that are too old
+	if strings.Contains(filepath.Base(dir), "@") {
+		st, err := os.Stat(dir)
+		if err != nil {
+			log.Printf("can't stat dir %s %v", dir, err)
+			return true
+		}
+		if st.ModTime().Before(r.onlyAfter) {
+			return true
+		}
+		if st.ModTime().After(r.onlyBefore) {
+			return true
+		}
+	}
+	return false
+}

vendor/golang.org/x/tools/internal/modindex/index.go

@@ -0,0 +1,266 @@
+// Copyright 2024 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 modindex
+
+import (
+	"bufio"
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"hash/crc64"
+	"io"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+)
+
+/*
+The on-disk index is a text file.
+The first 3 lines are header information containing CurrentVersion,
+the value of GOMODCACHE, and the validity date of the index.
+(This is when the code started building the index.)
+Following the header are sections of lines, one section for each
+import path. These sections are sorted by package name.
+The first line of each section, marked by a leading :, contains
+the package name, the import path, the name of the directory relative
+to GOMODCACHE, and its semantic version.
+The rest of each section consists of one line per exported symbol.
+The lines are sorted by the symbol's name and contain the name,
+an indication of its lexical type (C, T, V, F), and if it is the
+name of a function, information about the signature.
+
+The fields in the section header lines are separated by commas, and
+in the unlikely event this would be confusing, the csv package is used
+to write (and read) them.
+
+In the lines containing exported names, C=const, V=var, T=type, F=func.
+If it is a func, the next field is the number of returned values,
+followed by pairs consisting of formal parameter names and types.
+All these fields are separated by spaces. Any spaces in a type
+(e.g., chan struct{}) are replaced by $s on the disk. The $s are
+turned back into spaces when read.
+
+Here is an index header (the comments are not part of the index):
+0                                      // version (of the index format)
+/usr/local/google/home/pjw/go/pkg/mod  // GOMODCACHE
+2024-09-11 18:55:09                    // validity date of the index
+
+Here is an index section:
+:yaml,gopkg.in/yaml.v1,gopkg.in/yaml.v1@v1.0.0-20140924161607-9f9df34309c0,v1.0.0-20140924161607-9f9df34309c0
+Getter T
+Marshal F 2 in interface{}
+Setter T
+Unmarshal F 1 in []byte out interface{}
+
+The package name is yaml, the import path is gopkg.in/yaml.v1.
+Getter and Setter are types, and Marshal and Unmarshal are functions.
+The latter returns one value and has two arguments, 'in' and 'out'
+whose types are []byte and interface{}.
+*/
+
+// CurrentVersion tells readers about the format of the index.
+const CurrentVersion int = 0
+
+// Index is returned by ReadIndex().
+type Index struct {
+	Version  int
+	Cachedir Abspath   // The directory containing the module cache
+	Changed  time.Time // The index is up to date as of Changed
+	Entries  []Entry
+}
+
+// An Entry contains information for an import path.
+type Entry struct {
+	Dir        Relpath // directory in modcache
+	ImportPath string
+	PkgName    string
+	Version    string
+	//ModTime    STime    // is this useful?
+	Names []string // exported names and information
+}
+
+// IndexDir is where the module index is stored.
+var IndexDir string
+
+// Set IndexDir
+func init() {
+	var dir string
+	var err error
+	if testing.Testing() {
+		dir = os.TempDir()
+	} else {
+		dir, err = os.UserCacheDir()
+		// shouldn't happen, but TempDir is better than
+		// creating ./go/imports
+		if err != nil {
+			dir = os.TempDir()
+		}
+	}
+	dir = filepath.Join(dir, "go", "imports")
+	os.MkdirAll(dir, 0777)
+	IndexDir = dir
+}
+
+// ReadIndex reads the latest version of the on-disk index
+// for the cache directory cd.
+// It returns (nil, nil) if there is no index, but returns
+// a non-nil error if the index exists but could not be read.
+func ReadIndex(cachedir string) (*Index, error) {
+	cachedir, err := filepath.Abs(cachedir)
+	if err != nil {
+		return nil, err
+	}
+	cd := Abspath(cachedir)
+	dir := IndexDir
+	base := indexNameBase(cd)
+	iname := filepath.Join(dir, base)
+	buf, err := os.ReadFile(iname)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("cannot read %s: %w", iname, err)
+	}
+	fname := filepath.Join(dir, string(buf))
+	fd, err := os.Open(fname)
+	if err != nil {
+		return nil, err
+	}
+	defer fd.Close()
+	r := bufio.NewReader(fd)
+	ix, err := readIndexFrom(cd, r)
+	if err != nil {
+		return nil, err
+	}
+	return ix, nil
+}
+
+func readIndexFrom(cd Abspath, bx io.Reader) (*Index, error) {
+	b := bufio.NewScanner(bx)
+	var ans Index
+	// header
+	ok := b.Scan()
+	if !ok {
+		return nil, fmt.Errorf("unexpected scan error")
+	}
+	l := b.Text()
+	var err error
+	ans.Version, err = strconv.Atoi(l)
+	if err != nil {
+		return nil, err
+	}
+	if ans.Version != CurrentVersion {
+		return nil, fmt.Errorf("got version %d, expected %d", ans.Version, CurrentVersion)
+	}
+	if ok := b.Scan(); !ok {
+		return nil, fmt.Errorf("scanner error reading cachedir")
+	}
+	ans.Cachedir = Abspath(b.Text())
+	if ok := b.Scan(); !ok {
+		return nil, fmt.Errorf("scanner error reading index creation time")
+	}
+	// TODO(pjw): need to check that this is the expected cachedir
+	// so the tag should be passed in to this function
+	ans.Changed, err = time.ParseInLocation(time.DateTime, b.Text(), time.Local)
+	if err != nil {
+		return nil, err
+	}
+	var curEntry *Entry
+	for b.Scan() {
+		v := b.Text()
+		if v[0] == ':' {
+			if curEntry != nil {
+				ans.Entries = append(ans.Entries, *curEntry)
+			}
+			// as directories may contain commas and quotes, they need to be read as csv.
+			rdr := strings.NewReader(v[1:])
+			cs := csv.NewReader(rdr)
+			flds, err := cs.Read()
+			if err != nil {
+				return nil, err
+			}
+			if len(flds) != 4 {
+				return nil, fmt.Errorf("header contains %d fields, not 4: %q", len(v), v)
+			}
+			curEntry = &Entry{PkgName: flds[0], ImportPath: flds[1], Dir: toRelpath(cd, flds[2]), Version: flds[3]}
+			continue
+		}
+		curEntry.Names = append(curEntry.Names, v)
+	}
+	if curEntry != nil {
+		ans.Entries = append(ans.Entries, *curEntry)
+	}
+	if err := b.Err(); err != nil {
+		return nil, fmt.Errorf("scanner failed %v", err)
+	}
+	return &ans, nil
+}
+
+// write the index as a text file
+func writeIndex(cachedir Abspath, ix *Index) error {
+	ipat := fmt.Sprintf("index-%d-*", CurrentVersion)
+	fd, err := os.CreateTemp(IndexDir, ipat)
+	if err != nil {
+		return err // can this happen?
+	}
+	defer fd.Close()
+	if err := writeIndexToFile(ix, fd); err != nil {
+		return err
+	}
+	content := fd.Name()
+	content = filepath.Base(content)
+	base := indexNameBase(cachedir)
+	nm := filepath.Join(IndexDir, base)
+	err = os.WriteFile(nm, []byte(content), 0666)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func writeIndexToFile(x *Index, fd *os.File) error {
+	cnt := 0
+	w := bufio.NewWriter(fd)
+	fmt.Fprintf(w, "%d\n", x.Version)
+	fmt.Fprintf(w, "%s\n", x.Cachedir)
+	// round the time down
+	tm := x.Changed.Add(-time.Second / 2)
+	fmt.Fprintf(w, "%s\n", tm.Format(time.DateTime))
+	for _, e := range x.Entries {
+		if e.ImportPath == "" {
+			continue // shouldn't happen
+		}
+		// PJW: maybe always write these headers as csv?
+		if strings.ContainsAny(string(e.Dir), ",\"") {
+			log.Printf("DIR: %s", e.Dir)
+			cw := csv.NewWriter(w)
+			cw.Write([]string{":" + e.PkgName, e.ImportPath, string(e.Dir), e.Version})
+			cw.Flush()
+		} else {
+			fmt.Fprintf(w, ":%s,%s,%s,%s\n", e.PkgName, e.ImportPath, e.Dir, e.Version)
+		}
+		for _, x := range e.Names {
+			fmt.Fprintf(w, "%s\n", x)
+			cnt++
+		}
+	}
+	if err := w.Flush(); err != nil {
+		return err
+	}
+	return nil
+}
+
+// return the base name of the file containing the name of the current index
+func indexNameBase(cachedir Abspath) string {
+	// crc64 is a way to convert path names into 16 hex digits.
+	h := crc64.Checksum([]byte(cachedir), crc64.MakeTable(crc64.ECMA))
+	fname := fmt.Sprintf("index-name-%d-%016x", CurrentVersion, h)
+	return fname
+}

vendor/golang.org/x/tools/internal/modindex/lookup.go

@@ -0,0 +1,178 @@
+// Copyright 2024 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 modindex
+
+import (
+	"slices"
+	"strconv"
+	"strings"
+)
+
+type Candidate struct {
+	PkgName    string
+	Name       string
+	Dir        string
+	ImportPath string
+	Type       LexType
+	Deprecated bool
+	// information for Funcs
+	Results int16   // how many results
+	Sig     []Field // arg names and types
+}
+
+type Field struct {
+	Arg, Type string
+}
+
+type LexType int8
+
+const (
+	Const LexType = iota
+	Var
+	Type
+	Func
+)
+
+// LookupAll only returns those Candidates whose import path
+// finds all the nms.
+func (ix *Index) LookupAll(pkg string, names ...string) map[string][]Candidate {
+	// this can be made faster when benchmarks show that it needs to be
+	names = uniquify(names)
+	byImpPath := make(map[string][]Candidate)
+	for _, nm := range names {
+		cands := ix.Lookup(pkg, nm, false)
+		for _, c := range cands {
+			byImpPath[c.ImportPath] = append(byImpPath[c.ImportPath], c)
+		}
+	}
+	for k, v := range byImpPath {
+		if len(v) != len(names) {
+			delete(byImpPath, k)
+		}
+	}
+	return byImpPath
+}
+
+// remove duplicates
+func uniquify(in []string) []string {
+	if len(in) == 0 {
+		return in
+	}
+	in = slices.Clone(in)
+	slices.Sort(in)
+	return slices.Compact(in)
+}
+
+// Lookup finds all the symbols in the index with the given PkgName and name.
+// If prefix is true, it finds all of these with name as a prefix.
+func (ix *Index) Lookup(pkg, name string, prefix bool) []Candidate {
+	loc, ok := slices.BinarySearchFunc(ix.Entries, pkg, func(e Entry, pkg string) int {
+		return strings.Compare(e.PkgName, pkg)
+	})
+	if !ok {
+		return nil // didn't find the package
+	}
+	var ans []Candidate
+	// loc is the first entry for this package name, but there may be severeal
+	for i := loc; i < len(ix.Entries); i++ {
+		e := ix.Entries[i]
+		if e.PkgName != pkg {
+			break // end of sorted package names
+		}
+		nloc, ok := slices.BinarySearchFunc(e.Names, name, func(s string, name string) int {
+			if strings.HasPrefix(s, name) {
+				return 0
+			}
+			if s < name {
+				return -1
+			}
+			return 1
+		})
+		if !ok {
+			continue // didn't find the name, nor any symbols with name as a prefix
+		}
+		for j := nloc; j < len(e.Names); j++ {
+			nstr := e.Names[j]
+			// benchmarks show this makes a difference when there are a lot of Possibilities
+			flds := fastSplit(nstr)
+			if !(flds[0] == name || prefix && strings.HasPrefix(flds[0], name)) {
+				// past range of matching Names
+				break
+			}
+			if len(flds) < 2 {
+				continue // should never happen
+			}
+			px := Candidate{
+				PkgName:    pkg,
+				Name:       flds[0],
+				Dir:        string(e.Dir),
+				ImportPath: e.ImportPath,
+				Type:       asLexType(flds[1][0]),
+				Deprecated: len(flds[1]) > 1 && flds[1][1] == 'D',
+			}
+			if px.Type == Func {
+				n, err := strconv.Atoi(flds[2])
+				if err != nil {
+					continue // should never happen
+				}
+				px.Results = int16(n)
+				if len(flds) >= 4 {
+					sig := strings.Split(flds[3], " ")
+					for i := range sig {
+						// $ cannot otherwise occur. removing the spaces
+						// almost works, but for chan struct{}, e.g.
+						sig[i] = strings.Replace(sig[i], "$", " ", -1)
+					}
+					px.Sig = toFields(sig)
+				}
+			}
+			ans = append(ans, px)
+		}
+	}
+	return ans
+}
+
+func toFields(sig []string) []Field {
+	ans := make([]Field, len(sig)/2)
+	for i := range ans {
+		ans[i] = Field{Arg: sig[2*i], Type: sig[2*i+1]}
+	}
+	return ans
+}
+
+// benchmarks show this is measurably better than strings.Split
+// split into first 4 fields separated by single space
+func fastSplit(x string) []string {
+	ans := make([]string, 0, 4)
+	nxt := 0
+	start := 0
+	for i := 0; i < len(x); i++ {
+		if x[i] != ' ' {
+			continue
+		}
+		ans = append(ans, x[start:i])
+		nxt++
+		start = i + 1
+		if nxt >= 3 {
+			break
+		}
+	}
+	ans = append(ans, x[start:])
+	return ans
+}
+
+func asLexType(c byte) LexType {
+	switch c {
+	case 'C':
+		return Const
+	case 'V':
+		return Var
+	case 'T':
+		return Type
+	case 'F':
+		return Func
+	}
+	return -1
+}

vendor/golang.org/x/tools/internal/modindex/modindex.go

@@ -0,0 +1,164 @@
+// Copyright 2024 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 modindex contains code for building and searching an index to
+// the Go module cache. The directory containing the index, returned by
+// IndexDir(), contains a file index-name-<ver> that contains the name
+// of the current index. We believe writing that short file is atomic.
+// ReadIndex reads that file to get the file name of the index.
+// WriteIndex writes an index with a unique name and then
+// writes that name into a new version of index-name-<ver>.
+// (<ver> stands for the CurrentVersion of the index format.)
+package modindex
+
+import (
+	"path/filepath"
+	"slices"
+	"strings"
+	"time"
+
+	"golang.org/x/mod/semver"
+)
+
+// Create always creates a new index for the go module cache that is in cachedir.
+func Create(cachedir string) error {
+	_, err := indexModCache(cachedir, true)
+	return err
+}
+
+// Update the index for the go module cache that is in cachedir,
+// If there is no existing index it will build one.
+// If there are changed directories since the last index, it will
+// write a new one and return true. Otherwise it returns false.
+func Update(cachedir string) (bool, error) {
+	return indexModCache(cachedir, false)
+}
+
+// indexModCache writes an index current as of when it is called.
+// If clear is true the index is constructed from all of GOMODCACHE
+// otherwise the index is constructed from the last previous index
+// and the updates to the cache. It returns true if it wrote an index,
+// false otherwise.
+func indexModCache(cachedir string, clear bool) (bool, error) {
+	cachedir, err := filepath.Abs(cachedir)
+	if err != nil {
+		return false, err
+	}
+	cd := Abspath(cachedir)
+	future := time.Now().Add(24 * time.Hour) // safely in the future
+	ok, err := modindexTimed(future, cd, clear)
+	if err != nil {
+		return false, err
+	}
+	return ok, nil
+}
+
+// modindexTimed writes an index current as of onlyBefore.
+// If clear is true the index is constructed from all of GOMODCACHE
+// otherwise the index is constructed from the last previous index
+// and all the updates to the cache before onlyBefore.
+// It returns true if it wrote a new index, false if it wrote nothing.
+func modindexTimed(onlyBefore time.Time, cachedir Abspath, clear bool) (bool, error) {
+	var curIndex *Index
+	if !clear {
+		var err error
+		curIndex, err = ReadIndex(string(cachedir))
+		if clear && err != nil {
+			return false, err
+		}
+		// TODO(pjw): check that most of those directories still exist
+	}
+	cfg := &work{
+		onlyBefore: onlyBefore,
+		oldIndex:   curIndex,
+		cacheDir:   cachedir,
+	}
+	if curIndex != nil {
+		cfg.onlyAfter = curIndex.Changed
+	}
+	if err := cfg.buildIndex(); err != nil {
+		return false, err
+	}
+	if len(cfg.newIndex.Entries) == 0 && curIndex != nil {
+		// no changes from existing curIndex, don't write a new index
+		return false, nil
+	}
+	if err := cfg.writeIndex(); err != nil {
+		return false, err
+	}
+	return true, nil
+}
+
+type work struct {
+	onlyBefore time.Time // do not use directories later than this
+	onlyAfter  time.Time // only interested in directories after this
+	// directories from before onlyAfter come from oldIndex
+	oldIndex *Index
+	newIndex *Index
+	cacheDir Abspath
+}
+
+func (w *work) buildIndex() error {
+	// The effective date of the new index should be at least
+	// slightly earlier than when the directories are scanned
+	// so set it now.
+	w.newIndex = &Index{Changed: time.Now(), Cachedir: w.cacheDir}
+	dirs := findDirs(string(w.cacheDir), w.onlyAfter, w.onlyBefore)
+	if len(dirs) == 0 {
+		return nil
+	}
+	newdirs, err := byImportPath(dirs)
+	if err != nil {
+		return err
+	}
+	// for each import path it might occur only in newdirs,
+	// only in w.oldIndex, or in both.
+	// If it occurs in both, use the semantically later one
+	if w.oldIndex != nil {
+		for _, e := range w.oldIndex.Entries {
+			found, ok := newdirs[e.ImportPath]
+			if !ok {
+				w.newIndex.Entries = append(w.newIndex.Entries, e)
+				continue // use this one, there is no new one
+			}
+			if semver.Compare(found[0].version, e.Version) > 0 {
+				// use the new one
+			} else {
+				// use the old one, forget the new one
+				w.newIndex.Entries = append(w.newIndex.Entries, e)
+				delete(newdirs, e.ImportPath)
+			}
+		}
+	}
+	// get symbol information for all the new diredtories
+	getSymbols(w.cacheDir, newdirs)
+	// assemble the new index entries
+	for k, v := range newdirs {
+		d := v[0]
+		pkg, names := processSyms(d.syms)
+		if pkg == "" {
+			continue // PJW: does this ever happen?
+		}
+		entry := Entry{
+			PkgName:    pkg,
+			Dir:        d.path,
+			ImportPath: k,
+			Version:    d.version,
+			Names:      names,
+		}
+		w.newIndex.Entries = append(w.newIndex.Entries, entry)
+	}
+	// sort the entries in the new index
+	slices.SortFunc(w.newIndex.Entries, func(l, r Entry) int {
+		if n := strings.Compare(l.PkgName, r.PkgName); n != 0 {
+			return n
+		}
+		return strings.Compare(l.ImportPath, r.ImportPath)
+	})
+	return nil
+}
+
+func (w *work) writeIndex() error {
+	return writeIndex(w.cacheDir, w.newIndex)
+}

vendor/golang.org/x/tools/internal/modindex/symbols.go

@@ -0,0 +1,218 @@
+// Copyright 2024 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 modindex
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"os"
+	"path/filepath"
+	"runtime"
+	"slices"
+	"strings"
+
+	"golang.org/x/sync/errgroup"
+)
+
+// The name of a symbol contains information about the symbol:
+// <name> T for types, TD if the type is deprecated
+// <name> C for consts, CD if the const is deprecated
+// <name> V for vars, VD if the var is deprecated
+// and for funcs: <name> F <num of return values> (<arg-name> <arg-type>)*
+// any spaces in <arg-type> are replaced by $s so that the fields
+// of the name are space separated. F is replaced by FD if the func
+// is deprecated.
+type symbol struct {
+	pkg  string // name of the symbols's package
+	name string // declared name
+	kind string // T, C, V, or F, follwed by D if deprecated
+	sig  string // signature information, for F
+}
+
+// find the symbols for the best directories
+func getSymbols(cd Abspath, dirs map[string][]*directory) {
+	var g errgroup.Group
+	g.SetLimit(max(2, runtime.GOMAXPROCS(0)/2))
+	for _, vv := range dirs {
+		// throttling some day?
+		d := vv[0]
+		g.Go(func() error {
+			thedir := filepath.Join(string(cd), string(d.path))
+			mode := parser.SkipObjectResolution | parser.ParseComments
+
+			fi, err := os.ReadDir(thedir)
+			if err != nil {
+				return nil // log this someday?
+			}
+			for _, fx := range fi {
+				if !strings.HasSuffix(fx.Name(), ".go") || strings.HasSuffix(fx.Name(), "_test.go") {
+					continue
+				}
+				fname := filepath.Join(thedir, fx.Name())
+				tr, err := parser.ParseFile(token.NewFileSet(), fname, nil, mode)
+				if err != nil {
+					continue // ignore errors, someday log them?
+				}
+				d.syms = append(d.syms, getFileExports(tr)...)
+			}
+			return nil
+		})
+	}
+	g.Wait()
+}
+
+func getFileExports(f *ast.File) []symbol {
+	pkg := f.Name.Name
+	if pkg == "main" {
+		return nil
+	}
+	var ans []symbol
+	// should we look for //go:build ignore?
+	for _, decl := range f.Decls {
+		switch decl := decl.(type) {
+		case *ast.FuncDecl:
+			if decl.Recv != nil {
+				// ignore methods, as we are completing package selections
+				continue
+			}
+			name := decl.Name.Name
+			dtype := decl.Type
+			// not looking at dtype.TypeParams. That is, treating
+			// generic functions just like non-generic ones.
+			sig := dtype.Params
+			kind := "F"
+			if isDeprecated(decl.Doc) {
+				kind += "D"
+			}
+			result := []string{fmt.Sprintf("%d", dtype.Results.NumFields())}
+			for _, x := range sig.List {
+				// This code creates a string representing the type.
+				// TODO(pjw): it may be fragile:
+				// 1. x.Type could be nil, perhaps in ill-formed code
+				// 2. ExprString might someday change incompatibly to
+				//    include struct tags, which can be arbitrary strings
+				if x.Type == nil {
+					// Can this happen without a parse error? (Files with parse
+					// errors are ignored in getSymbols)
+					continue // maybe report this someday
+				}
+				tp := types.ExprString(x.Type)
+				if len(tp) == 0 {
+					// Can this happen?
+					continue // maybe report this someday
+				}
+				// This is only safe if ExprString never returns anything with a $
+				// The only place a $ can occur seems to be in a struct tag, which
+				// can be an arbitrary string literal, and ExprString does not presently
+				// print struct tags. So for this to happen the type of a formal parameter
+				// has to be a explict struct, e.g. foo(x struct{a int "$"}) and ExprString
+				// would have to show the struct tag. Even testing for this case seems
+				// a waste of effort, but let's remember the possibility
+				if strings.Contains(tp, "$") {
+					continue
+				}
+				tp = strings.Replace(tp, " ", "$", -1)
+				if len(x.Names) == 0 {
+					result = append(result, "_")
+					result = append(result, tp)
+				} else {
+					for _, y := range x.Names {
+						result = append(result, y.Name)
+						result = append(result, tp)
+					}
+				}
+			}
+			sigs := strings.Join(result, " ")
+			if s := newsym(pkg, name, kind, sigs); s != nil {
+				ans = append(ans, *s)
+			}
+		case *ast.GenDecl:
+			depr := isDeprecated(decl.Doc)
+			switch decl.Tok {
+			case token.CONST, token.VAR:
+				tp := "V"
+				if decl.Tok == token.CONST {
+					tp = "C"
+				}
+				if depr {
+					tp += "D"
+				}
+				for _, sp := range decl.Specs {
+					for _, x := range sp.(*ast.ValueSpec).Names {
+						if s := newsym(pkg, x.Name, tp, ""); s != nil {
+							ans = append(ans, *s)
+						}
+					}
+				}
+			case token.TYPE:
+				tp := "T"
+				if depr {
+					tp += "D"
+				}
+				for _, sp := range decl.Specs {
+					if s := newsym(pkg, sp.(*ast.TypeSpec).Name.Name, tp, ""); s != nil {
+						ans = append(ans, *s)
+					}
+				}
+			}
+		}
+	}
+	return ans
+}
+
+func newsym(pkg, name, kind, sig string) *symbol {
+	if len(name) == 0 || !ast.IsExported(name) {
+		return nil
+	}
+	sym := symbol{pkg: pkg, name: name, kind: kind, sig: sig}
+	return &sym
+}
+
+func isDeprecated(doc *ast.CommentGroup) bool {
+	if doc == nil {
+		return false
+	}
+	// go.dev/wiki/Deprecated Paragraph starting 'Deprecated:'
+	// This code fails for /* Deprecated: */, but it's the code from
+	// gopls/internal/analysis/deprecated
+	lines := strings.Split(doc.Text(), "\n\n")
+	for _, line := range lines {
+		if strings.HasPrefix(line, "Deprecated:") {
+			return true
+		}
+	}
+	return false
+}
+
+// return the package name and the value for the symbols.
+// if there are multiple packages, choose one arbitrarily
+// the returned slice is sorted lexicographically
+func processSyms(syms []symbol) (string, []string) {
+	if len(syms) == 0 {
+		return "", nil
+	}
+	slices.SortFunc(syms, func(l, r symbol) int {
+		return strings.Compare(l.name, r.name)
+	})
+	pkg := syms[0].pkg
+	var names []string
+	for _, s := range syms {
+		var nx string
+		if s.pkg == pkg {
+			if s.sig != "" {
+				nx = fmt.Sprintf("%s %s %s", s.name, s.kind, s.sig)
+			} else {
+				nx = fmt.Sprintf("%s %s", s.name, s.kind)
+			}
+			names = append(names, nx)
+		} else {
+			continue // PJW: do we want to keep track of these?
+		}
+	}
+	return pkg, names
+}

vendor/golang.org/x/tools/internal/modindex/types.go

@@ -0,0 +1,25 @@
+// Copyright 2024 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 modindex
+
+import (
+	"strings"
+)
+
+// some special types to avoid confusions
+
+// distinguish various types of directory names. It's easy to get confused.
+type Abspath string // absolute paths
+type Relpath string // paths with GOMODCACHE prefix removed
+
+func toRelpath(cachedir Abspath, s string) Relpath {
+	if strings.HasPrefix(s, string(cachedir)) {
+		if s == string(cachedir) {
+			return Relpath("")
+		}
+		return Relpath(s[len(cachedir)+1:])
+	}
+	return Relpath(s)
+}