go/doc: recursively inspect selector expressions

Also adds a couple of simple tests for doc.Examples.

Fixes #4561.

R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/7067048

diff --git a/src/pkg/go/doc/example.go b/src/pkg/go/doc/example.go
index d9e8c39a540e92951d9ab538a08e04ffd4c4f6f1..c7a0cf8c6d302d5968a740f50080680bcbb9213c 100644 (file)
--- a/src/pkg/go/doc/example.go
+++ b/src/pkg/go/doc/example.go
@@ -148,13 +148,13 @@ func playExample(file *ast.File, body *ast.BlockStmt) *ast.File {
        // Find unresolved identifiers and uses of top-level declarations.
        unresolved := make(map[string]bool)
        usesTopDecl := false
-       ast.Inspect(body, func(n ast.Node) bool {
-               // For an expression like fmt.Println, only add "fmt" to the
-               // set of unresolved names.
+       var inspectFunc func(ast.Node) bool
+       inspectFunc = func(n ast.Node) bool {
+               // For selector expressions, only inspect the left hand side.
+               // (For an expression like fmt.Println, only add "fmt" to the
+               // set of unresolved names, not "Println".)
                if e, ok := n.(*ast.SelectorExpr); ok {
-                       if id, ok := e.X.(*ast.Ident); ok && id.Obj == nil {
-                               unresolved[id.Name] = true
-                       }
+                       ast.Inspect(e.X, inspectFunc)
                        return false
                }
                if id, ok := n.(*ast.Ident); ok {
@@ -165,7 +165,8 @@ func playExample(file *ast.File, body *ast.BlockStmt) *ast.File {
                        }
                }
                return true
-       })
+       }
+       ast.Inspect(body, inspectFunc)
        if usesTopDecl {
                // We don't support examples that are not self-contained (yet).
                return nil

diff --git a/src/pkg/go/doc/example_test.go b/src/pkg/go/doc/example_test.go
new file mode 100644 (file)
index 0000000..b70efd9
--- /dev/null
+++ b/src/pkg/go/doc/example_test.go
@@ -0,0 +1,111 @@
+// Copyright 2013 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 doc_test
+
+import (
+       "bytes"
+       "go/doc"
+       "go/format"
+       "go/parser"
+       "go/token"
+       "strings"
+       "testing"
+)
+
+const exampleTestFile = `
+package foo_test
+
+import (
+       "fmt"
+       "log"
+       "os/exec"
+)
+
+func ExampleHello() {
+       fmt.Println("Hello, world!")
+       // Output: Hello, world!
+}
+
+func ExampleImport() {
+       out, err := exec.Command("date").Output()
+       if err != nil {
+               log.Fatal(err)
+       }
+       fmt.Printf("The date is %s\n", out)
+}
+`
+
+var exampleTestCases = []struct {
+       Name, Play, Output string
+}{
+       {
+               Name:   "Hello",
+               Play:   exampleHelloPlay,
+               Output: "Hello, world!\n",
+       },
+       {
+               Name: "Import",
+               Play: exampleImportPlay,
+       },
+}
+
+const exampleHelloPlay = `package main
+
+import (
+       "fmt"
+)
+
+func main() {
+       fmt.Println("Hello, world!")
+}
+`
+const exampleImportPlay = `package main
+
+import (
+       "fmt"
+       "log"
+       "os/exec"
+)
+
+func main() {
+       out, err := exec.Command("date").Output()
+       if err != nil {
+               log.Fatal(err)
+       }
+       fmt.Printf("The date is %s\n", out)
+}
+`
+
+func TestExamples(t *testing.T) {
+       fs := token.NewFileSet()
+       file, err := parser.ParseFile(fs, "test.go", strings.NewReader(exampleTestFile), parser.ParseComments)
+       if err != nil {
+               t.Fatal(err)
+       }
+       for i, e := range doc.Examples(file) {
+               c := exampleTestCases[i]
+               if e.Name != c.Name {
+                       t.Errorf("got Name == %q, want %q", e.Name, c.Name)
+               }
+               if w := c.Play; w != "" {
+                       var g string // hah
+                       if e.Play == nil {
+                               g = "<nil>"
+                       } else {
+                               b := new(bytes.Buffer)
+                               if err := format.Node(b, fs, e.Play); err != nil {
+                                       t.Fatal(err)
+                               }
+                               g = b.String()
+                       }
+                       if g != w {
+                               t.Errorf("%s: got Play == %q, want %q", c.Name, g, w)
+                       }
+               }
+               if g, w := e.Output, c.Output; g != w {
+                       t.Errorf("%s: got Output == %q, want %q", c.Name, g, w)
+               }
+       }
+}