cmd/go: fix -outputdir -coverprofile interaction

The CL introducing merged handling of cover profiles
did not correctly account for the fact that the file name argument
to -coverprofile is required to be interpreted relative to
the -outputdir argument.

Fixes #22804.

Change-Id: I804774013c12187313b8fd2044302978bdbb6697
Reviewed-on: https://go-review.googlesource.com/81455
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/go/go_test.go

@@ -2476,7 +2476,7 @@ func TestCoverageFunc(t *testing.T) {
 	tg.makeTempdir()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
 
-	tg.run("test", "-coverprofile="+filepath.Join(tg.tempdir, "cover.out"), "coverasm")
+	tg.run("test", "-outputdir="+tg.tempdir, "-coverprofile=cover.out", "coverasm")
 	tg.run("tool", "cover", "-func="+filepath.Join(tg.tempdir, "cover.out"))
 	tg.grepStdout(`\tg\t*100.0%`, "did not find g 100% covered")
 	tg.grepStdoutNot(`\tf\t*[0-9]`, "reported coverage for assembly function f")

src/cmd/go/internal/test/cover.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"path/filepath"
 	"sync"
 )
 
@@ -25,6 +26,9 @@ func initCoverProfile() {
 	if testCoverProfile == "" {
 		return
 	}
+	if !filepath.IsAbs(testCoverProfile) && testOutputDir != "" {
+		testCoverProfile = filepath.Join(testOutputDir, testCoverProfile)
+	}
 
 	// No mutex - caller's responsibility to call with no racing goroutines.
 	f, err := os.Create(testCoverProfile)

src/cmd/go/internal/test/test.go

@@ -466,6 +466,7 @@ var (
 	testCoverPaths   []string        // -coverpkg flag
 	testCoverPkgs    []*load.Package // -coverpkg flag
 	testCoverProfile string          // -coverprofile flag
+	testOutputDir    string          // -outputdir flag
 	testO            string          // -o flag
 	testProfile      string          // profiling flag that limits test to one package
 	testNeedBinary   bool            // profile needs to keep binary around

src/cmd/go/internal/test/testflag.go

@@ -88,7 +88,6 @@ func init() {
 //	go test -x math
 func testFlags(args []string) (packageNames, passToTest []string) {
 	inPkg := false
-	outputDir := ""
 	var explicitArgs []string
 	for i := 0; i < len(args); i++ {
 		if !strings.HasPrefix(args[i], "-") {
@@ -180,7 +179,7 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 				}
 				testCover = true
 			case "outputdir":
-				outputDir = value
+				testOutputDir = value
 			case "vet":
 				testVetList = value
 			}
@@ -220,7 +219,7 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 	}
 
 	// Tell the test what directory we're running in, so it can write the profiles there.
-	if testProfile != "" && outputDir == "" {
+	if testProfile != "" && testOutputDir == "" {
 		dir, err := os.Getwd()
 		if err != nil {
 			base.Fatalf("error from os.Getwd: %s", err)