[dev.regabi] cmd/compile: remove fmt_test code; it has outlived its usefulness

With the recent compiler rewrites and cleanups to gc/fmt.go, the
"safety net" provided by fmt_test has become less important and
the test itself has become a burden (often breaks because of small
format changes elsewhere).

Eventually, the syntax and types2 packages will provide most error
and diagnostic compiler output at which point fmt.go can be further
simplified as well.

Change-Id: Ie93eefd3e1166f3548fed0199b732dbd6c81948a
Reviewed-on: https://go-review.googlesource.com/c/go/+/282560
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

src/cmd/compile/fmt_test.go

@@ -1,615 +0,0 @@
-// Copyright 2016 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.
-
-// This file implements TestFormats; a test that verifies
-// format strings in the compiler (this directory and all
-// subdirectories, recursively).
-//
-// TestFormats finds potential (Printf, etc.) format strings.
-// If they are used in a call, the format verbs are verified
-// based on the matching argument type against a precomputed
-// map of valid formats (knownFormats). This map can be used to
-// automatically rewrite format strings across all compiler
-// files with the -r flag.
-//
-// The format map needs to be updated whenever a new (type,
-// format) combination is found and the format verb is not
-// 'v' or 'T' (as in "%v" or "%T"). To update the map auto-
-// matically from the compiler source's use of format strings,
-// use the -u flag. (Whether formats are valid for the values
-// to be formatted must be verified manually, of course.)
-//
-// The -v flag prints out the names of all functions called
-// with a format string, the names of files that were not
-// processed, and any format rewrites made (with -r).
-//
-// Run as: go test -run Formats [-r][-u][-v]
-//
-// Known shortcomings:
-// - indexed format strings ("%[2]s", etc.) are not supported
-//   (the test will fail)
-// - format strings that are not simple string literals cannot
-//   be updated automatically
-//   (the test will fail with respective warnings)
-// - format strings in _test packages outside the current
-//   package are not processed
-//   (the test will report those files)
-//
-package main_test
-
-import (
-	"bytes"
-	"flag"
-	"fmt"
-	"go/ast"
-	"go/build"
-	"go/constant"
-	"go/format"
-	"go/importer"
-	"go/parser"
-	"go/token"
-	"go/types"
-	"internal/testenv"
-	"io"
-	"io/fs"
-	"io/ioutil"
-	"log"
-	"os"
-	"path/filepath"
-	"sort"
-	"strconv"
-	"strings"
-	"testing"
-	"unicode/utf8"
-)
-
-var (
-	rewrite = flag.Bool("r", false, "rewrite format strings")
-	update  = flag.Bool("u", false, "update known formats")
-)
-
-// The following variables collect information across all processed files.
-var (
-	fset          = token.NewFileSet()
-	formatStrings = make(map[*ast.BasicLit]bool)      // set of all potential format strings found
-	foundFormats  = make(map[string]bool)             // set of all formats found
-	callSites     = make(map[*ast.CallExpr]*callSite) // map of all calls
-)
-
-// A File is a corresponding (filename, ast) pair.
-type File struct {
-	name string
-	ast  *ast.File
-}
-
-func TestFormats(t *testing.T) {
-	if testing.Short() && testenv.Builder() == "" {
-		t.Skip("Skipping in short mode")
-	}
-	testenv.MustHaveGoBuild(t) // more restrictive than necessary, but that's ok
-
-	// process all directories
-	filepath.WalkDir(".", func(path string, info fs.DirEntry, err error) error {
-		if info.IsDir() {
-			if info.Name() == "testdata" {
-				return filepath.SkipDir
-			}
-
-			importPath := filepath.Join("cmd/compile", path)
-			if ignoredPackages[filepath.ToSlash(importPath)] {
-				return filepath.SkipDir
-			}
-
-			pkg, err := build.Import(importPath, path, 0)
-			if err != nil {
-				if _, ok := err.(*build.NoGoError); ok {
-					return nil // nothing to do here
-				}
-				t.Fatal(err)
-			}
-			collectPkgFormats(t, pkg)
-		}
-		return nil
-	})
-
-	// test and rewrite formats
-	updatedFiles := make(map[string]File) // files that were rewritten
-	for _, p := range callSites {
-		// test current format literal and determine updated one
-		out := formatReplace(p.str, func(index int, in string) string {
-			if in == "*" {
-				return in // cannot rewrite '*' (as in "%*d")
-			}
-			// in != '*'
-			typ := p.types[index]
-			format := typ + " " + in // e.g., "*Node %n"
-
-			// Do not bother reporting basic types, nor %v, %T, %p.
-			// Vet handles basic types, and those three formats apply to all types.
-			if !strings.Contains(typ, ".") || (in == "%v" || in == "%T" || in == "%p") {
-				return in
-			}
-
-			// check if format is known
-			out, known := knownFormats[format]
-
-			// record format if not yet found
-			_, found := foundFormats[format]
-			if !found {
-				foundFormats[format] = true
-			}
-
-			// report an error if the format is unknown and this is the first
-			// time we see it; ignore "%v" and "%T" which are always valid
-			if !known && !found && in != "%v" && in != "%T" {
-				t.Errorf("%s: unknown format %q for %s argument", posString(p.arg), in, typ)
-			}
-
-			if out == "" {
-				out = in
-			}
-			return out
-		})
-
-		// replace existing format literal if it changed
-		if out != p.str {
-			// we cannot replace the argument if it's not a string literal for now
-			// (e.g., it may be "foo" + "bar")
-			lit, ok := p.arg.(*ast.BasicLit)
-			if !ok {
-				delete(callSites, p.call) // treat as if we hadn't found this site
-				continue
-			}
-
-			if testing.Verbose() {
-				fmt.Printf("%s:\n\t- %q\n\t+ %q\n", posString(p.arg), p.str, out)
-			}
-
-			// find argument index of format argument
-			index := -1
-			for i, arg := range p.call.Args {
-				if p.arg == arg {
-					index = i
-					break
-				}
-			}
-			if index < 0 {
-				// we may have processed the same call site twice,
-				// but that shouldn't happen
-				panic("internal error: matching argument not found")
-			}
-
-			// replace literal
-			new := *lit                    // make a copy
-			new.Value = strconv.Quote(out) // this may introduce "-quotes where there were `-quotes
-			p.call.Args[index] = &new
-			updatedFiles[p.file.name] = p.file
-		}
-	}
-
-	// write dirty files back
-	var filesUpdated bool
-	if len(updatedFiles) > 0 && *rewrite {
-		for _, file := range updatedFiles {
-			var buf bytes.Buffer
-			if err := format.Node(&buf, fset, file.ast); err != nil {
-				t.Errorf("WARNING: gofmt %s failed: %v", file.name, err)
-				continue
-			}
-			if err := ioutil.WriteFile(file.name, buf.Bytes(), 0x666); err != nil {
-				t.Errorf("WARNING: writing %s failed: %v", file.name, err)
-				continue
-			}
-			fmt.Printf("updated %s\n", file.name)
-			filesUpdated = true
-		}
-	}
-
-	// report the names of all functions called with a format string
-	if len(callSites) > 0 && testing.Verbose() {
-		set := make(map[string]bool)
-		for _, p := range callSites {
-			set[nodeString(p.call.Fun)] = true
-		}
-		var list []string
-		for s := range set {
-			list = append(list, s)
-		}
-		fmt.Println("\nFunctions called with a format string")
-		writeList(os.Stdout, list)
-	}
-
-	// update formats
-	if len(foundFormats) > 0 && *update {
-		var list []string
-		for s := range foundFormats {
-			list = append(list, fmt.Sprintf("%q: \"\",", s))
-		}
-		var buf bytes.Buffer
-		buf.WriteString(knownFormatsHeader)
-		writeList(&buf, list)
-		buf.WriteString("}\n")
-		out, err := format.Source(buf.Bytes())
-		const outfile = "fmtmap_test.go"
-		if err != nil {
-			t.Errorf("WARNING: gofmt %s failed: %v", outfile, err)
-			out = buf.Bytes() // continue with unformatted source
-		}
-		if err = ioutil.WriteFile(outfile, out, 0644); err != nil {
-			t.Errorf("WARNING: updating format map failed: %v", err)
-		}
-	}
-
-	// check that knownFormats is up to date
-	if !*rewrite && !*update {
-		var mismatch bool
-		for s := range foundFormats {
-			if _, ok := knownFormats[s]; !ok {
-				mismatch = true
-				break
-			}
-		}
-		if !mismatch {
-			for s := range knownFormats {
-				if _, ok := foundFormats[s]; !ok {
-					mismatch = true
-					break
-				}
-			}
-		}
-		if mismatch {
-			t.Errorf("format map is out of date; run 'go test -u' to update and manually verify correctness of change'")
-		}
-	}
-
-	// all format strings of calls must be in the formatStrings set (self-verification)
-	for _, p := range callSites {
-		if lit, ok := p.arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
-			if formatStrings[lit] {
-				// ok
-				delete(formatStrings, lit)
-			} else {
-				// this should never happen
-				panic(fmt.Sprintf("internal error: format string not found (%s)", posString(lit)))
-			}
-		}
-	}
-
-	// if we have any strings left, we may need to update them manually
-	if len(formatStrings) > 0 && filesUpdated {
-		var list []string
-		for lit := range formatStrings {
-			list = append(list, fmt.Sprintf("%s: %s", posString(lit), nodeString(lit)))
-		}
-		fmt.Println("\nWARNING: Potentially missed format strings")
-		writeList(os.Stdout, list)
-		t.Fail()
-	}
-
-	fmt.Println()
-}
-
-// A callSite describes a function call that appears to contain
-// a format string.
-type callSite struct {
-	file  File
-	call  *ast.CallExpr // call containing the format string
-	arg   ast.Expr      // format argument (string literal or constant)
-	str   string        // unquoted format string
-	types []string      // argument types
-}
-
-func collectPkgFormats(t *testing.T, pkg *build.Package) {
-	// collect all files
-	var filenames []string
-	filenames = append(filenames, pkg.GoFiles...)
-	filenames = append(filenames, pkg.CgoFiles...)
-	filenames = append(filenames, pkg.TestGoFiles...)
-
-	// TODO(gri) verify _test files outside package
-	for _, name := range pkg.XTestGoFiles {
-		// don't process this test itself
-		if name != "fmt_test.go" && testing.Verbose() {
-			fmt.Printf("WARNING: %s not processed\n", filepath.Join(pkg.Dir, name))
-		}
-	}
-
-	// make filenames relative to .
-	for i, name := range filenames {
-		filenames[i] = filepath.Join(pkg.Dir, name)
-	}
-
-	// parse all files
-	files := make([]*ast.File, len(filenames))
-	for i, filename := range filenames {
-		f, err := parser.ParseFile(fset, filename, nil, parser.ParseComments)
-		if err != nil {
-			t.Fatal(err)
-		}
-		files[i] = f
-	}
-
-	// typecheck package
-	conf := types.Config{Importer: importer.Default()}
-	etypes := make(map[ast.Expr]types.TypeAndValue)
-	if _, err := conf.Check(pkg.ImportPath, fset, files, &types.Info{Types: etypes}); err != nil {
-		t.Fatal(err)
-	}
-
-	// collect all potential format strings (for extra verification later)
-	for _, file := range files {
-		ast.Inspect(file, func(n ast.Node) bool {
-			if s, ok := stringLit(n); ok && isFormat(s) {
-				formatStrings[n.(*ast.BasicLit)] = true
-			}
-			return true
-		})
-	}
-
-	// collect all formats/arguments of calls with format strings
-	for index, file := range files {
-		ast.Inspect(file, func(n ast.Node) bool {
-			if call, ok := n.(*ast.CallExpr); ok {
-				if ignoredFunctions[nodeString(call.Fun)] {
-					return true
-				}
-				// look for an arguments that might be a format string
-				for i, arg := range call.Args {
-					if s, ok := stringVal(etypes[arg]); ok && isFormat(s) {
-						// make sure we have enough arguments
-						n := numFormatArgs(s)
-						if i+1+n > len(call.Args) {
-							t.Errorf("%s: not enough format args (ignore %s?)", posString(call), nodeString(call.Fun))
-							break // ignore this call
-						}
-						// assume last n arguments are to be formatted;
-						// determine their types
-						argTypes := make([]string, n)
-						for i, arg := range call.Args[len(call.Args)-n:] {
-							if tv, ok := etypes[arg]; ok {
-								argTypes[i] = typeString(tv.Type)
-							}
-						}
-						// collect call site
-						if callSites[call] != nil {
-							panic("internal error: file processed twice?")
-						}
-						callSites[call] = &callSite{
-							file:  File{filenames[index], file},
-							call:  call,
-							arg:   arg,
-							str:   s,
-							types: argTypes,
-						}
-						break // at most one format per argument list
-					}
-				}
-			}
-			return true
-		})
-	}
-}
-
-// writeList writes list in sorted order to w.
-func writeList(w io.Writer, list []string) {
-	sort.Strings(list)
-	for _, s := range list {
-		fmt.Fprintln(w, "\t", s)
-	}
-}
-
-// posString returns a string representation of n's position
-// in the form filename:line:col: .
-func posString(n ast.Node) string {
-	if n == nil {
-		return ""
-	}
-	return fset.Position(n.Pos()).String()
-}
-
-// nodeString returns a string representation of n.
-func nodeString(n ast.Node) string {
-	var buf bytes.Buffer
-	if err := format.Node(&buf, fset, n); err != nil {
-		log.Fatal(err) // should always succeed
-	}
-	return buf.String()
-}
-
-// typeString returns a string representation of n.
-func typeString(typ types.Type) string {
-	s := filepath.ToSlash(typ.String())
-
-	// Report all the concrete IR types as Node, to shorten fmtmap.
-	const ir = "cmd/compile/internal/ir."
-	if s == "*"+ir+"Name" || s == "*"+ir+"Func" || s == "*"+ir+"Decl" ||
-		s == ir+"Ntype" || s == ir+"Expr" || s == ir+"Stmt" ||
-		strings.HasPrefix(s, "*"+ir) && (strings.HasSuffix(s, "Expr") || strings.HasSuffix(s, "Stmt")) {
-		return "cmd/compile/internal/ir.Node"
-	}
-
-	return s
-}
-
-// stringLit returns the unquoted string value and true if
-// n represents a string literal; otherwise it returns ""
-// and false.
-func stringLit(n ast.Node) (string, bool) {
-	if lit, ok := n.(*ast.BasicLit); ok && lit.Kind == token.STRING {
-		s, err := strconv.Unquote(lit.Value)
-		if err != nil {
-			log.Fatal(err) // should not happen with correct ASTs
-		}
-		return s, true
-	}
-	return "", false
-}
-
-// stringVal returns the (unquoted) string value and true if
-// tv is a string constant; otherwise it returns "" and false.
-func stringVal(tv types.TypeAndValue) (string, bool) {
-	if tv.IsValue() && tv.Value != nil && tv.Value.Kind() == constant.String {
-		return constant.StringVal(tv.Value), true
-	}
-	return "", false
-}
-
-// formatIter iterates through the string s in increasing
-// index order and calls f for each format specifier '%..v'.
-// The arguments for f describe the specifier's index range.
-// If a format specifier contains a "*", f is called with
-// the index range for "*" alone, before being called for
-// the entire specifier. The result of f is the index of
-// the rune at which iteration continues.
-func formatIter(s string, f func(i, j int) int) {
-	i := 0     // index after current rune
-	var r rune // current rune
-
-	next := func() {
-		r1, w := utf8.DecodeRuneInString(s[i:])
-		if w == 0 {
-			r1 = -1 // signal end-of-string
-		}
-		r = r1
-		i += w
-	}
-
-	flags := func() {
-		for r == ' ' || r == '#' || r == '+' || r == '-' || r == '0' {
-			next()
-		}
-	}
-
-	index := func() {
-		if r == '[' {
-			log.Fatalf("cannot handle indexed arguments: %s", s)
-		}
-	}
-
-	digits := func() {
-		index()
-		if r == '*' {
-			i = f(i-1, i)
-			next()
-			return
-		}
-		for '0' <= r && r <= '9' {
-			next()
-		}
-	}
-
-	for next(); r >= 0; next() {
-		if r == '%' {
-			i0 := i
-			next()
-			flags()
-			digits()
-			if r == '.' {
-				next()
-				digits()
-			}
-			index()
-			// accept any letter (a-z, A-Z) as format verb;
-			// ignore anything else
-			if 'a' <= r && r <= 'z' || 'A' <= r && r <= 'Z' {
-				i = f(i0-1, i)
-			}
-		}
-	}
-}
-
-// isFormat reports whether s contains format specifiers.
-func isFormat(s string) (yes bool) {
-	formatIter(s, func(i, j int) int {
-		yes = true
-		return len(s) // stop iteration
-	})
-	return
-}
-
-// oneFormat reports whether s is exactly one format specifier.
-func oneFormat(s string) (yes bool) {
-	formatIter(s, func(i, j int) int {
-		yes = i == 0 && j == len(s)
-		return j
-	})
-	return
-}
-
-// numFormatArgs returns the number of format specifiers in s.
-func numFormatArgs(s string) int {
-	count := 0
-	formatIter(s, func(i, j int) int {
-		count++
-		return j
-	})
-	return count
-}
-
-// formatReplace replaces the i'th format specifier s in the incoming
-// string in with the result of f(i, s) and returns the new string.
-func formatReplace(in string, f func(i int, s string) string) string {
-	var buf []byte
-	i0 := 0
-	index := 0
-	formatIter(in, func(i, j int) int {
-		if sub := in[i:j]; sub != "*" { // ignore calls for "*" width/length specifiers
-			buf = append(buf, in[i0:i]...)
-			buf = append(buf, f(index, sub)...)
-			i0 = j
-		}
-		index++
-		return j
-	})
-	return string(append(buf, in[i0:]...))
-}
-
-// ignoredPackages is the set of packages which can
-// be ignored.
-var ignoredPackages = map[string]bool{}
-
-// ignoredFunctions is the set of functions which may have
-// format-like arguments but which don't do any formatting and
-// thus may be ignored.
-var ignoredFunctions = map[string]bool{}
-
-func init() {
-	// verify that knownFormats entries are correctly formatted
-	for key, val := range knownFormats {
-		// key must be "typename format", and format starts with a '%'
-		// (formats containing '*' alone are not collected in this map)
-		i := strings.Index(key, "%")
-		if i < 0 || !oneFormat(key[i:]) {
-			log.Fatalf("incorrect knownFormats key: %q", key)
-		}
-		// val must be "format" or ""
-		if val != "" && !oneFormat(val) {
-			log.Fatalf("incorrect knownFormats value: %q (key = %q)", val, key)
-		}
-	}
-}
-
-const knownFormatsHeader = `// Copyright 2018 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.
-
-// This file implements the knownFormats map which records the valid
-// formats for a given type. The valid formats must correspond to
-// supported compiler formats implemented in fmt.go, or whatever
-// other format verbs are implemented for the given type. The map may
-// also be used to change the use of a format verb across all compiler
-// sources automatically (for instance, if the implementation of fmt.go
-// changes), by using the -r option together with the new formats in the
-// map. To generate this file automatically from the existing source,
-// run: go test -run Formats -u.
-//
-// See the package comment in fmt_test.go for additional information.
-
-package main_test
-
-// knownFormats entries are of the form "typename format" -> "newformat".
-// An absent entry means that the format is not recognized as valid.
-// An empty new format means that the format should remain unchanged.
-var knownFormats = map[string]string{
-`

src/cmd/compile/fmtmap_test.go

@@ -1,75 +0,0 @@
-// Copyright 2018 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.
-
-// This file implements the knownFormats map which records the valid
-// formats for a given type. The valid formats must correspond to
-// supported compiler formats implemented in fmt.go, or whatever
-// other format verbs are implemented for the given type. The map may
-// also be used to change the use of a format verb across all compiler
-// sources automatically (for instance, if the implementation of fmt.go
-// changes), by using the -r option together with the new formats in the
-// map. To generate this file automatically from the existing source,
-// run: go test -run Formats -u.
-//
-// See the package comment in fmt_test.go for additional information.
-
-package main_test
-
-// knownFormats entries are of the form "typename format" -> "newformat".
-// An absent entry means that the format is not recognized as valid.
-// An empty new format means that the format should remain unchanged.
-var knownFormats = map[string]string{
-	"*bytes.Buffer %s":                             "",
-	"*cmd/compile/internal/ssa.Block %s":           "",
-	"*cmd/compile/internal/ssa.Func %s":            "",
-	"*cmd/compile/internal/ssa.Register %s":        "",
-	"*cmd/compile/internal/ssa.Value %s":           "",
-	"*cmd/compile/internal/types.Sym %+v":          "",
-	"*cmd/compile/internal/types.Sym %S":           "",
-	"*cmd/compile/internal/types.Type %+v":         "",
-	"*cmd/compile/internal/types.Type %-S":         "",
-	"*cmd/compile/internal/types.Type %L":          "",
-	"*cmd/compile/internal/types.Type %S":          "",
-	"*cmd/compile/internal/types.Type %s":          "",
-	"*math/big.Float %f":                           "",
-	"*math/big.Int %s":                             "",
-	"[]cmd/compile/internal/syntax.token %s":       "",
-	"cmd/compile/internal/arm.shift %d":            "",
-	"cmd/compile/internal/gc.RegIndex %d":          "",
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-}