cmd/cover: include a package name in the HTML title

A recent change added a title to the HTML coverage report but neglected to include the package name. Add the package name here. It's a little trickier than you'd think because there may be multiple packages and we don't want to parse the files, so we just extract a directory name from the path of the first file. This will almost always be right, and has the advantage that it gives a better result for package main. There are rare cases it will get wrong, but that will be no hardship. If this turns out not to be good enough, we can refine it. Fixes golang#38609 Change-Id: I2201f6caef906e0b0258b90d7de518879041fe72 Reviewed-on: https://go-review.googlesource.com/c/go/+/230517 Reviewed-by: Ian Lance Taylor <[email protected]> Run-TryBot: Ian Lance Taylor <[email protected]> TryBot-Result: Gobot Gobot <[email protected]>
random-zebra · Apr 30, 2020 · 41f6388 · 41f6388
1 parent 1d31f9b
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diff --git a/src/cmd/cover/html.go b/src/cmd/cover/html.go
@@ -172,6 +172,27 @@ type templateData struct {
 	Set   bool
 }
 
+// PackageName returns a name for the package being shown.
+// It does this by choosing the penultimate element of the path
+// name, so foo.bar/baz/foo.go chooses 'baz'. This is cheap
+// and easy, avoids parsing the Go file, and gets a better answer
+// for package main. It returns the empty string if there is
+// a problem.
+func (td templateData) PackageName() string {
+	if len(td.Files) == 0 {
+		return ""
+	}
+	fileName := td.Files[0].Name
+	elems := strings.Split(fileName, "/") // Package path is always slash-separated.
+	// Return the penultimate non-empty element.
+	for i := len(elems) - 2; i >= 0; i-- {
+		if elems[i] != "" {
+			return elems[i]
+		}
+	}
+	return ""
+}
+
 type templateFile struct {
 	Name     string
 	Body     template.HTML
@@ -183,7 +204,7 @@ const tmplHTML = `
 <html>
 	<head>
 		<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-		<title>Go Coverage Report</title>
+		<title>{{$pkg := .PackageName}}{{if $pkg}}{{$pkg}}: {{end}}Go Coverage Report</title>
 		<style>
 			body {
 				background: black;

diff --git a/src/cmd/cover/pkgname_test.go b/src/cmd/cover/pkgname_test.go
@@ -0,0 +1,31 @@
+// Copyright 2020 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 main
+
+import "testing"
+
+func TestPackageName(t *testing.T) {
+	var tests = []struct {
+		fileName, pkgName string
+	}{
+		{"", ""},
+		{"///", ""},
+		{"fmt", ""}, // No Go file, improper form.
+		{"fmt/foo.go", "fmt"},
+		{"encoding/binary/foo.go", "binary"},
+		{"encoding/binary/////foo.go", "binary"},
+	}
+	var tf templateFile
+	for _, test := range tests {
+		tf.Name = test.fileName
+		td := templateData{
+			Files: []*templateFile{&tf},
+		}
+		got := td.PackageName()
+		if got != test.pkgName {
+			t.Errorf("%s: got %s want %s", test.fileName, got, test.pkgName)
+		}
+	}
+}