cmd/doc: add -all flag to print all documentation for package

Unlike the one for the old godoc, you need the -u flag to see
unexported symbols. This seems like the right behavior: it's
consistent.

For now at least, the argument must be a package, not a symbol.
This is also different from old godoc.

Required a little refactoring but also cleaned up a few things.

Update #25595

Leaving the bug open for now until we tackle
	go doc -all symbol

Change-Id: Ibc1975bfa592cb1e92513eb2e5e9e11e01a60095
Reviewed-on: https://go-review.googlesource.com/c/141977
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/doc/doc_test.go

@@ -147,6 +147,69 @@ var tests = []test{
 			`type T1 T2`,                       // Type alias does not display as type declaration.
 		},
 	},
+	// Package dump -all
+	{
+		"full package",
+		[]string{"-all", p},
+		[]string{
+			`package pkg .*import`,
+			`Package comment`,
+			`CONSTANTS`,
+			`Comment before ConstOne`,
+			`ConstOne = 1`,
+			`ConstTwo = 2 // Comment on line with ConstTwo`,
+			`ConstFive`,
+			`ConstSix`,
+			`Const block where first entry is unexported`,
+			`ConstLeft2, constRight2 uint64`,
+			`constLeft3, ConstRight3`,
+			`ConstLeft4, ConstRight4`,
+			`Duplicate = iota`,
+			`const CaseMatch = 1`,
+			`const Casematch = 2`,
+			`const ExportedConstant = 1`,
+			`const MultiLineConst = `,
+			`MultiLineString1`,
+			`VARIABLES`,
+			`Comment before VarOne`,
+			`VarOne = 1`,
+			`Comment about block of variables`,
+			`VarFive = 5`,
+			`var ExportedVariable = 1`,
+			`var LongLine = newLongLine\(`,
+			`var MultiLineVar = map\[struct {`,
+			`FUNCTIONS`,
+			`func ExportedFunc\(a int\) bool`,
+			`Comment about exported function`,
+			`func MultiLineFunc\(x interface`,
+			`func ReturnUnexported\(\) unexportedType`,
+			`TYPES`,
+			`type ExportedInterface interface`,
+			`type ExportedStructOneField struct`,
+			`type ExportedType struct`,
+			`Comment about exported type`,
+			`const ConstGroup4 ExportedType = ExportedType`,
+			`ExportedTypedConstant ExportedType = iota`,
+			`Constants tied to ExportedType`,
+			`func ExportedTypeConstructor\(\) \*ExportedType`,
+			`Comment about constructor for exported type`,
+			`func ReturnExported\(\) ExportedType`,
+			`func \(ExportedType\) ExportedMethod\(a int\) bool`,
+			`Comment about exported method`,
+			`type T1 = T2`,
+			`type T2 int`,
+		},
+		[]string{
+			`constThree`,
+			`_, _ uint64 = 2 \* iota, 1 << iota`,
+			`constLeft1, constRight1`,
+			`duplicate`,
+			`varFour`,
+			`func internalFunc`,
+			`unexportedField`,
+			`func \(unexportedType\)`,
+		},
+	},
 	// Package dump -u
 	{
 		"full package with u",
@@ -164,6 +227,58 @@ var tests = []test{
 			`MultiLine(String|Method|Field)`,   // No data from multi line portions.
 		},
 	},
+	// Package dump -u -all
+	{
+		"full package",
+		[]string{"-u", "-all", p},
+		[]string{
+			`package pkg .*import`,
+			`Package comment`,
+			`CONSTANTS`,
+			`Comment before ConstOne`,
+			`ConstOne += 1`,
+			`ConstTwo += 2 // Comment on line with ConstTwo`,
+			`constThree = 3 // Comment on line with constThree`,
+			`ConstFive`,
+			`const internalConstant += 2`,
+			`Comment about internal constant`,
+			`VARIABLES`,
+			`Comment before VarOne`,
+			`VarOne += 1`,
+			`Comment about block of variables`,
+			`varFour += 4`,
+			`VarFive += 5`,
+			`varSix += 6`,
+			`var ExportedVariable = 1`,
+			`var LongLine = newLongLine\(`,
+			`var MultiLineVar = map\[struct {`,
+			`var internalVariable = 2`,
+			`Comment about internal variable`,
+			`FUNCTIONS`,
+			`func ExportedFunc\(a int\) bool`,
+			`Comment about exported function`,
+			`func MultiLineFunc\(x interface`,
+			`func internalFunc\(a int\) bool`,
+			`Comment about internal function`,
+			`func newLongLine\(ss .*string\)`,
+			`TYPES`,
+			`type ExportedType struct`,
+			`type T1 = T2`,
+			`type T2 int`,
+			`type unexportedType int`,
+			`Comment about unexported type`,
+			`ConstGroup1 unexportedType = iota`,
+			`ConstGroup2`,
+			`ConstGroup3`,
+			`ExportedTypedConstant_unexported unexportedType = iota`,
+			`Constants tied to unexportedType`,
+			`const unexportedTypedConstant unexportedType = 1`,
+			`func ReturnUnexported\(\) unexportedType`,
+			`func \(unexportedType\) ExportedMethod\(\) bool`,
+			`func \(unexportedType\) unexportedMethod\(\) bool`,
+		},
+		nil,
+	},
 
 	// Single constant.
 	{
@@ -361,7 +476,6 @@ var tests = []test{
 			`io.Reader.*Comment on line with embedded Reader`,
 		},
 		[]string{
-			`int.*embedded`,                 // No unexported embedded field.
 			`Comment about exported method`, // No comment about exported method.
 			`unexportedMethod`,              // No unexported method.
 			`unexportedTypedConstant`,       // No unexported constant.

src/cmd/doc/main.go

@@ -31,6 +31,9 @@
 // The -src flag causes doc to print the full source code for the symbol, such
 // as the body of a struct, function or method.
 //
+// The -all flag causes doc to print all documentation for the package and
+// all its visible symbols. The argument must identify a package.
+//
 // For complete documentation, run "go help doc".
 package main
 
@@ -52,6 +55,7 @@ import (
 var (
 	unexported bool // -u flag
 	matchCase  bool // -c flag
+	showAll    bool // -all flag
 	showCmd    bool // -cmd flag
 	showSrc    bool // -src flag
 )
@@ -88,6 +92,7 @@ func do(writer io.Writer, flagSet *flag.FlagSet, args []string) (err error) {
 	matchCase = false
 	flagSet.BoolVar(&unexported, "u", false, "show unexported symbols as well as exported")
 	flagSet.BoolVar(&matchCase, "c", false, "symbol matching honors case (paths not affected)")
+	flagSet.BoolVar(&showAll, "all", false, "show all documentation for package")
 	flagSet.BoolVar(&showCmd, "cmd", false, "show symbols with package docs even if package is a command")
 	flagSet.BoolVar(&showSrc, "src", false, "show source code for symbol")
 	flagSet.Parse(args)
@@ -127,6 +132,15 @@ func do(writer io.Writer, flagSet *flag.FlagSet, args []string) (err error) {
 			unexported = true
 		}
 
+		// We have a package.
+		if showAll {
+			if symbol != "" {
+				return fmt.Errorf("-all valid only for package, not symbol: %s", symbol)
+			}
+			pkg.allDoc()
+			return
+		}
+
 		switch {
 		case symbol == "":
 			pkg.packageDoc() // The package exists, so we got some output.

src/cmd/go/alldocs.go

@@ -342,6 +342,8 @@
 // 	cd go/src/encoding/json; go doc decode
 //
 // Flags:
+// 	-all
+// 		Show all the documentation for the package.
 // 	-c
 // 		Respect case when matching symbols.
 // 	-cmd

src/cmd/go/internal/doc/doc.go

@@ -106,6 +106,8 @@ Examples:
 	cd go/src/encoding/json; go doc decode
 
 Flags:
+	-all
+		Show all the documentation for the package.
 	-c
 		Respect case when matching symbols.
 	-cmd