cmd/go/internal/load: trim the " (test)" suffix from ImportStack paths

We were passing untrimmed paths to ModPackageModuleInfo, which was then failing
the build because it was asked to resolve an invalid path.

Fixes #26722

Change-Id: I043cc9c26f2188c5e005c0353620d9c55b339df9
Reviewed-on: https://go-review.googlesource.com/127795
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index 1b21b632b87cc9713f77c355cf40a6051fd384e8..f27fdc17674005a7fc33bf139272a7993ca1e1ef 100644 (file)
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -318,7 +318,8 @@ func (p *PackageError) Error() string {
        return "package " + strings.Join(p.ImportStack, "\n\timports ") + ": " + p.Err
 }
 
-// An ImportStack is a stack of import paths.
+// An ImportStack is a stack of import paths, possibly with the suffix " (test)" appended.
+// TODO(bcmills): When the tree opens for 1.12, replace the suffixed string with a struct.
 type ImportStack []string
 
 func (s *ImportStack) Push(p string) {
@@ -986,7 +987,7 @@ func disallowInternal(srcDir string, p *Package, stk *ImportStack) *Package {
                // p is in a module, so make it available based on the import path instead
                // of the file path (https://golang.org/issue/23970).
                parent := p.ImportPath[:i]
-               importer := (*stk)[len(*stk)-2]
+               importer := strings.TrimSuffix((*stk)[len(*stk)-2], " (test)")
                if str.HasPathPrefix(importer, parent) {
                        return p
                }
@@ -1039,7 +1040,7 @@ func disallowVendor(srcDir, path string, p *Package, stk *ImportStack) *Package
                // but the usual vendor visibility check will not catch them
                // because the module loader presents them with an ImportPath starting
                // with "golang_org/" instead of "vendor/".
-               importer := (*stk)[len(*stk)-2]
+               importer := strings.TrimSuffix((*stk)[len(*stk)-2], " (test)")
                if mod := ModPackageModuleInfo(importer); mod != nil {
                        dir := p.Dir
                        if relDir, err := filepath.Rel(p.Root, p.Dir); err == nil {

diff --git a/src/cmd/go/testdata/script/mod_test.txt b/src/cmd/go/testdata/script/mod_test.txt
new file mode 100644 (file)
index 0000000..a1ee8aa
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_test.txt
@@ -0,0 +1,18 @@
+env GO111MODULE=on
+
+cd a/
+go test
+stdout PASS
+
+-- a/go.mod --
+module github.com/user/a
+
+-- a/a.go --
+package a
+
+-- a/a_test.go --
+package a
+
+import "testing"
+
+func Test(t *testing.T) {}