cmd/go: fix problems with coverage percentage reporting w/ -coverpkg

This patch resolves a set of problems with "percent covered" metrics
reported when the "-coverpkg" is in effect; these bugs were introduced
in Go 1.22 with the rollout of CL 495452 and related changes.
Specifically, for runs with multiple packages selected but without
-coverpkg, "percent covered" metrics were generated for package P not
based just on P's statements but on the entire corpus of statements.

Fixes #65570.

Change-Id: I38d61886cb46ebd38d8c4313c326d671197c3568
Reviewed-on: https://go-review.googlesource.com/c/go/+/592205
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Matloob <matloob@golang.org>

diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
index 73e66ddcc22df9a83f28c51cf43127c4d8ac2895..d29f64a51cc9703ca5ad30c67565bed3c79358f5 100644 (file)
--- a/src/cmd/go/internal/load/test.go
+++ b/src/cmd/go/internal/load/test.go
@@ -683,6 +683,22 @@ func (t *testFuncs) Covered() string {
        return " in " + strings.Join(t.Cover.Paths, ", ")
 }
 
+func (t *testFuncs) CoverSelectedPackages() string {
+       if t.Cover == nil || t.Cover.Paths == nil {
+               return `[]string{"` + t.Package.ImportPath + `"}`
+       }
+       var sb strings.Builder
+       fmt.Fprintf(&sb, "[]string{")
+       for k, p := range t.Cover.Pkgs {
+               if k != 0 {
+                       sb.WriteString(", ")
+               }
+               fmt.Fprintf(&sb, `"%s"`, p.ImportPath)
+       }
+       sb.WriteString("}")
+       return sb.String()
+}
+
 // Tested returns the name of the package being tested.
 func (t *testFuncs) Tested() string {
        return t.Package.Name
@@ -950,6 +966,7 @@ func init() {
 {{if .Cover}}
        testdeps.CoverMode = {{printf "%q" .Cover.Mode}}
        testdeps.Covered = {{printf "%q" .Covered}}
+       testdeps.CoverSelectedPackages = {{printf "%s" .CoverSelectedPackages}}
        testdeps.CoverSnapshotFunc = cfile.Snapshot
        testdeps.CoverProcessTestDirFunc = cfile.ProcessCoverTestDir
        testdeps.CoverMarkProfileEmittedFunc = cfile.MarkProfileEmitted

diff --git a/src/cmd/go/testdata/script/cover_single_vs_multiple.txt b/src/cmd/go/testdata/script/cover_single_vs_multiple.txt
new file mode 100644 (file)
index 0000000..47fbae8
--- /dev/null
+++ b/src/cmd/go/testdata/script/cover_single_vs_multiple.txt
@@ -0,0 +1,63 @@
+# Without -coverpkg, we should get the same value for a given
+# package regardless of how many other packages are selected
+# (see issue 65570).
+
+[short] skip
+
+go test -count=1 -cover ./a ./b ./main
+stdout '^ok\s+M/main\s+\S+\s+coverage: 75.0% of statements'
+go test -count=1 -cover ./main
+stdout '^ok\s+M/main\s+\S+\s+coverage: 75.0% of statements'
+
+-- go.mod --
+module M
+
+go 1.21
+-- a/a.go --
+package a
+
+func AFunc() int {
+       return 42
+}
+-- b/b.go --
+package b
+
+func BFunc() int {
+       return -42
+}
+-- main/main.go --
+package main
+
+import (
+       "M/a"
+)
+
+func MFunc() string {
+       return "42"
+}
+
+func M2Func() int {
+       return a.AFunc()
+}
+
+func init() {
+       println("package 'main' init")
+}
+
+func main() {
+       println(a.AFunc())
+}
+-- main/main_test.go --
+package main
+
+import "testing"
+
+func TestMain(t *testing.T) {
+       if MFunc() != "42" {
+               t.Fatalf("bad!")
+       }
+       if M2Func() != 42 {
+               t.Fatalf("also bad!")
+       }
+}
+

diff --git a/src/internal/coverage/cfile/testsupport.go b/src/internal/coverage/cfile/testsupport.go
index 72d09150cf7566bfdb5c05c798bc6d6d328c8446..3594b32aee1a8df4bb740c2c05be9a21eedfd4af 100644 (file)
--- a/src/internal/coverage/cfile/testsupport.go
+++ b/src/internal/coverage/cfile/testsupport.go
@@ -27,7 +27,7 @@ import (
 // testmain code when "go test -cover" is in effect. It is not
 // intended to be used other than internally by the Go command's
 // generated code.
-func ProcessCoverTestDir(dir string, cfile string, cm string, cpkg string, w io.Writer) error {
+func ProcessCoverTestDir(dir string, cfile string, cm string, cpkg string, w io.Writer, selpkgs []string) error {
        cmode := coverage.ParseCounterMode(cm)
        if cmode == coverage.CtrModeInvalid {
                return fmt.Errorf("invalid counter mode %q", cm)
@@ -103,7 +103,7 @@ func ProcessCoverTestDir(dir string, cfile string, cm string, cpkg string, w io.
        }
 
        // Emit percent.
-       if err := ts.cf.EmitPercent(w, nil, cpkg, true, true); err != nil {
+       if err := ts.cf.EmitPercent(w, selpkgs, cpkg, true, true); err != nil {
                return err
        }
 

diff --git a/src/internal/coverage/cfile/ts_test.go b/src/internal/coverage/cfile/ts_test.go
index fa05c82eece01c249fbfb596a804918a623e7c07..d3441821a436d31786a68560a9429e383aee5dae 100644 (file)
--- a/src/internal/coverage/cfile/ts_test.go
+++ b/src/internal/coverage/cfile/ts_test.go
@@ -45,7 +45,7 @@ func TestTestSupport(t *testing.T) {
        textfile := filepath.Join(t.TempDir(), "file.txt")
        var sb strings.Builder
        err := ProcessCoverTestDir(tgcd, textfile,
-               testing.CoverMode(), "", &sb)
+               testing.CoverMode(), "", &sb, nil)
        if err != nil {
                t.Fatalf("bad: %v", err)
        }
@@ -168,7 +168,7 @@ func TestAuxMetaDataFiles(t *testing.T) {
        var sb strings.Builder
        textfile := filepath.Join(td, "file2.txt")
        err = ProcessCoverTestDir(tgcd, textfile,
-               testing.CoverMode(), "", &sb)
+               testing.CoverMode(), "", &sb, nil)
        if err != nil {
                t.Fatalf("bad: %v", err)
        }

diff --git a/src/testing/internal/testdeps/deps.go b/src/testing/internal/testdeps/deps.go
index 3b5dc7198f5c85821b65b02990995924ca871a9d..6f42d4722ca00cf3aae60ad550aad65acca75c98 100644 (file)
--- a/src/testing/internal/testdeps/deps.go
+++ b/src/testing/internal/testdeps/deps.go
@@ -203,6 +203,7 @@ func (TestDeps) SnapshotCoverage() {
 
 var CoverMode string
 var Covered string
+var CoverSelectedPackages []string
 
 // These variables below are set at runtime (via code in testmain) to point
 // to the equivalent functions in package internal/coverage/cfile; doing
@@ -210,7 +211,7 @@ var Covered string
 // only when -cover is in effect (as opposed to importing for all tests).
 var (
        CoverSnapshotFunc           func() float64
-       CoverProcessTestDirFunc     func(dir string, cfile string, cm string, cpkg string, w io.Writer) error
+       CoverProcessTestDirFunc     func(dir string, cfile string, cm string, cpkg string, w io.Writer, selpkgs []string) error
        CoverMarkProfileEmittedFunc func(val bool)
 )
 
@@ -232,7 +233,7 @@ func coverTearDown(coverprofile string, gocoverdir string) (string, error) {
        }
        CoverMarkProfileEmittedFunc(true)
        cmode := CoverMode
-       if err := CoverProcessTestDirFunc(gocoverdir, coverprofile, cmode, Covered, os.Stdout); err != nil {
+       if err := CoverProcessTestDirFunc(gocoverdir, coverprofile, cmode, Covered, os.Stdout, CoverSelectedPackages); err != nil {
                return "error generating coverage report", err
        }
        return "", nil