cmd/go: allow full flag processing in go vet

This allows the go tool to run "go vet" with both the build flags
that make sense, such as -x and -tags, and vet with all its flags.

To do this, create a new package cmd/go/internal/cmdflag to
hold functionality common to flag handling for test and vet.

Fixes #19350

RELNOTES=yes

Change-Id: Ia1ae213bd3f6cab1c5e492501c8d43ce61a7ee89
Reviewed-on: https://go-review.googlesource.com/40112
Reviewed-by: Russ Cox <[email protected]>

Author: robpike

src/cmd/dist/deps.go

@@ -21,10 +21,11 @@ var builddeps = map[string][]string{
 	"cmd/go/internal/load":              {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/buildid", "cmd/go/internal/cfg", "cmd/go/internal/str", "compress/flate", "compress/zlib", "context", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding/binary", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "hash/adler32", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "math/bits", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
 	"cmd/go/internal/run":               {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/buildid", "cmd/go/internal/cfg", "cmd/go/internal/load", "cmd/go/internal/str", "cmd/go/internal/work", "compress/flate", "compress/zlib", "container/heap", "context", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding/binary", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "hash/adler32", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "math/bits", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
 	"cmd/go/internal/str":               {"bytes", "errors", "fmt", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "math", "os", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "strconv", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},
-	"cmd/go/internal/test":              {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/buildid", "cmd/go/internal/cfg", "cmd/go/internal/load", "cmd/go/internal/str", "cmd/go/internal/work", "compress/flate", "compress/zlib", "container/heap", "context", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding/binary", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "hash/adler32", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "math/bits", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
+	"cmd/go/internal/test":              {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/buildid", "cmd/go/internal/cfg", "cmd/go/internal/cmdflag", "cmd/go/internal/load", "cmd/go/internal/str", "cmd/go/internal/work", "compress/flate", "compress/zlib", "container/heap", "context", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding/binary", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "hash/adler32", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "math/bits", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
 	"cmd/go/internal/tool":              {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/cfg", "cmd/go/internal/str", "context", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
 	"cmd/go/internal/version":           {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/cfg", "cmd/go/internal/str", "context", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
-	"cmd/go/internal/vet":               {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/buildid", "cmd/go/internal/cfg", "cmd/go/internal/load", "cmd/go/internal/str", "cmd/go/internal/work", "compress/flate", "compress/zlib", "container/heap", "context", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding/binary", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "hash/adler32", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "math/bits", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
+	"cmd/go/internal/cmdflag":           {"cmd/go/internal/base", "flag", "fmt", "os", "strconv", "strings"},
+	"cmd/go/internal/vet":               {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/buildid", "cmd/go/internal/cfg", "cmd/go/internal/cmdflag", "cmd/go/internal/load", "cmd/go/internal/str", "cmd/go/internal/work", "compress/flate", "compress/zlib", "container/heap", "context", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding/binary", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "hash/adler32", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "math/bits", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
 	"cmd/go/internal/web":               {"errors", "internal/race", "io", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sync", "sync/atomic"},
 	"cmd/go/internal/work":              {"bufio", "bytes", "cmd/go/internal/base", "cmd/go/internal/buildid", "cmd/go/internal/cfg", "cmd/go/internal/load", "cmd/go/internal/str", "compress/flate", "compress/zlib", "container/heap", "context", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding/binary", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "hash/adler32", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "io/ioutil", "log", "math", "math/bits", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
 	"compress/flate":                    {"bufio", "bytes", "errors", "fmt", "internal/poll", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "internal/syscall/windows/sysdll", "io", "math", "math/bits", "os", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},

src/cmd/go/alldocs.go

@@ -798,15 +798,13 @@
 //
 // Usage:
 //
-// 	go vet [-n] [-x] [build flags] [packages]
+// 	go vet [-n] [-x] [build flags] [vet flags] [packages]
 //
 // Vet runs the Go vet command on the packages named by the import paths.
 //
-// For more about vet, see 'go doc cmd/vet'.
+// For more about vet and its flags, see 'go doc cmd/vet'.
 // For more about specifying packages, see 'go help packages'.
 //
-// To run the vet tool with specific options, run 'go tool vet'.
-//
 // The -n flag prints commands that would be executed.
 // The -x flag prints commands as they are executed.
 //

src/cmd/go/go_test.go

@@ -2650,8 +2650,6 @@ func TestGoGetInternalWildcard(t *testing.T) {
 }
 
 func TestGoVetWithExternalTests(t *testing.T) {
-	testenv.MustHaveExternalNetwork(t)
-
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.makeTempdir()
@@ -2662,15 +2660,32 @@ func TestGoVetWithExternalTests(t *testing.T) {
 }
 
 func TestGoVetWithTags(t *testing.T) {
-	testenv.MustHaveExternalNetwork(t)
-
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.makeTempdir()
 	tg.run("install", "cmd/vet")
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
 	tg.runFail("vet", "-tags", "tagtest", "vetpkg")
-	tg.grepBoth(`c\.go.*wrong number of args for format`, "go get vetpkg did not run scan tagged file")
+	tg.grepBoth(`c\.go.*wrong number of args for format`, "go vet vetpkg did not run scan tagged file")
+}
+
+func TestGoVetWithFlagsOn(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.makeTempdir()
+	tg.run("install", "cmd/vet")
+	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
+	tg.runFail("vet", "-printf", "vetpkg")
+	tg.grepBoth("missing argument for Printf", "go vet -printf vetpkg did not find missing argument for Printf")
+}
+
+func TestGoVetWithFlagsOff(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.makeTempdir()
+	tg.run("install", "cmd/vet")
+	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
+	tg.run("vet", "-printf=false", "vetpkg")
 }
 
 // Issue 9767, 19769.

src/cmd/go/internal/cmdflag/flag.go

@@ -0,0 +1,123 @@
+// Copyright 2017 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 cmdflag handles flag processing common to several go tools.
+package cmdflag
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"cmd/go/internal/base"
+)
+
+// The flag handling part of go commands such as test is large and distracting.
+// We can't use the standard flag package because some of the flags from
+// our command line are for us, and some are for the binary we're running,
+// and some are for both.
+
+// Defn defines a flag we know about.
+type Defn struct {
+	Name       string     // Name on command line.
+	BoolVar    *bool      // If it's a boolean flag, this points to it.
+	Value      flag.Value // The flag.Value represented.
+	PassToTest bool       // Pass to the test binary? Used only by go test.
+	Present    bool       // Flag has been seen.
+}
+
+// IsBool reports whether v is a bool flag.
+func IsBool(v flag.Value) bool {
+	vv, ok := v.(interface {
+		IsBoolFlag() bool
+	})
+	if ok {
+		return vv.IsBoolFlag()
+	}
+	return false
+}
+
+// SetBool sets the addressed boolean to the value.
+func SetBool(cmd string, flag *bool, value string) {
+	x, err := strconv.ParseBool(value)
+	if err != nil {
+		SyntaxError(cmd, "illegal bool flag value "+value)
+	}
+	*flag = x
+}
+
+// SetInt sets the addressed integer to the value.
+func SetInt(cmd string, flag *int, value string) {
+	x, err := strconv.Atoi(value)
+	if err != nil {
+		SyntaxError(cmd, "illegal int flag value "+value)
+	}
+	*flag = x
+}
+
+// SyntaxError reports an argument syntax error and exits the program.
+func SyntaxError(cmd, msg string) {
+	fmt.Fprintf(os.Stderr, "go %s: %s\n", cmd, msg)
+	if cmd == "test" {
+		fmt.Fprintf(os.Stderr, `run "go help %s" or "go help testflag" for more information`+"\n", cmd)
+	} else {
+		fmt.Fprintf(os.Stderr, `run "go help %s" for more information`+"\n", cmd)
+	}
+	os.Exit(2)
+}
+
+// Parse sees if argument i is present in the definitions and if so,
+// returns its definition, value, and whether it consumed an extra word.
+// If the flag begins (cmd+".") it is ignored for the purpose of this function.
+func Parse(cmd string, defns []*Defn, args []string, i int) (f *Defn, value string, extra bool) {
+	arg := args[i]
+	if strings.HasPrefix(arg, "--") { // reduce two minuses to one
+		arg = arg[1:]
+	}
+	switch arg {
+	case "-?", "-h", "-help":
+		base.Usage()
+	}
+	if arg == "" || arg[0] != '-' {
+		return
+	}
+	name := arg[1:]
+	// If there's already a prefix such as "test.", drop it for now.
+	name = strings.TrimPrefix(name, cmd+".")
+	equals := strings.Index(name, "=")
+	if equals >= 0 {
+		value = name[equals+1:]
+		name = name[:equals]
+	}
+	for _, f = range defns {
+		if name == f.Name {
+			// Booleans are special because they have modes -x, -x=true, -x=false.
+			if f.BoolVar != nil || IsBool(f.Value) {
+				if equals < 0 { // Otherwise, it's been set and will be verified in SetBool.
+					value = "true"
+				} else {
+					// verify it parses
+					SetBool(cmd, new(bool), value)
+				}
+			} else { // Non-booleans must have a value.
+				extra = equals < 0
+				if extra {
+					if i+1 >= len(args) {
+						SyntaxError(cmd, "missing argument for flag "+f.Name)
+					}
+					value = args[i+1]
+				}
+			}
+			if f.Present {
+				SyntaxError(cmd, f.Name+" flag may be set only once")
+			}
+			f.Present = true
+			return
+		}
+	}
+	f = nil
+	return
+}