Fix linking submodule of go workspace

internal/link/link.go

@@ -12,8 +12,9 @@ import (
 	"sort"
 	"strings"
 
-	"github.com/ironcore-dev/vgopath/internal/module"
 	"github.com/spf13/pflag"
+
+	"github.com/ironcore-dev/vgopath/internal/module"
 )
 
 type Node struct {
@@ -261,7 +262,17 @@ func linkNode(dir string, node Node) error {
 			return err
 		}
 
+		childNames := make(map[string]struct{}, len(node.Children))
+		for _, child := range node.Children {
+			childNames[child.Segment] = struct{}{}
+		}
+
 		for _, entry := range entries {
+			// skip linking directories of the module hierarchy, they will be handled by a dedicated call
+			if _, ok := childNames[entry.Name()]; ok {
+				continue
+			}
+
 			srcPath := filepath.Join(srcDir, entry.Name())
 			dstPath := filepath.Join(dstDir, entry.Name())
 			if err := os.Symlink(srcPath, dstPath); err != nil {

internal/link/link_test.go

@@ -8,52 +8,64 @@ import (
 	"go/build"
 	"os"
 	"path/filepath"
+	"slices"
 
-	. "github.com/ironcore-dev/vgopath/internal/link"
-	"github.com/ironcore-dev/vgopath/internal/module"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/format"
 	"github.com/onsi/gomega/types"
+
+	. "github.com/ironcore-dev/vgopath/internal/link"
+	"github.com/ironcore-dev/vgopath/internal/module"
 )
 
 var _ = Describe("Internal", func() {
 	var (
 		tmpDir                                                            string
 		moduleA, moduleB, moduleB1, moduleB11, moduleB2, moduleC, moduleD module.Module
+		allModules                                                        []module.Module
 	)
 	BeforeEach(func() {
 		var err error
 		tmpDir, err = os.MkdirTemp("", "test")
 		Expect(err).NotTo(HaveOccurred())
 
+		allModules = []module.Module{}
 		moduleA = module.Module{
 			Path: "a",
-			Dir:  "/tmp/a",
+			Dir:  filepath.Join("a"),
 			Main: true,
 		}
+		allModules = append(allModules, moduleA)
 		moduleB = module.Module{
 			Path: "example.org/b",
-			Dir:  "/tmp/example.org/b",
+			Dir:  filepath.Join("example.org", "b"),
 		}
+		allModules = append(allModules, moduleB)
 		moduleB1 = module.Module{
 			Path: "example.org/b/1",
-			Dir:  "/tmp/example.org/b/1",
+			Dir:  filepath.Join("example.org", "b", "1"),
 		}
+		allModules = append(allModules, moduleB1)
 		moduleB11 = module.Module{
 			Path: "example.org/b/1/1",
-			Dir:  "/tmp/example.org/b/1/1",
+			Dir:  filepath.Join("example.org", "b", "1", "1"),
 		}
+		allModules = append(allModules, moduleB11)
 		moduleB2 = module.Module{
 			Path: "example.org/b/2",
-			Dir:  "/tmp/example.org/b/2",
+			Dir:  filepath.Join("example.org", "b", "2"),
 		}
+		allModules = append(allModules, moduleB2)
 		moduleC = module.Module{
 			Path: "example.org/user/c",
-			Dir:  "/tmp/example.org/user/c",
+			Dir:  filepath.Join("example.org", "user", "c"),
 		}
+		allModules = append(allModules, moduleC)
 		moduleD = module.Module{
 			Path: "example.org/d",
 		}
+		allModules = append(allModules, moduleD)
 	})
 	AfterEach(func() {
 		if tmpDir != "" {
@@ -138,6 +150,28 @@ var _ = Describe("Internal", func() {
 			Expect(os.MkdirAll(dstGopathDir, 0777)).To(Succeed())
 		})
 
+		Describe("Nodes", func() {
+			It("should correctly handle submodules", func() {
+				Expect(makeModules(srcGopathDir, &moduleB, &moduleB1, &moduleB11, &moduleB2)).NotTo(HaveOccurred())
+
+				nodes, err := BuildModuleNodes([]module.Module{moduleB, moduleB1, moduleB11, moduleB2})
+				Expect(err).NotTo(HaveOccurred())
+
+				Expect(Nodes(dstGopathDir, nodes)).To(Succeed())
+
+				Expect(dstGopathDir).To(HaveEntries(map[string]types.GomegaMatcher{
+					filepath.Join("example.org", "b"):                     BeADirectory(),
+					filepath.Join("example.org", "b", "go.mod"):           BeASymlinkTo(filepath.Join(moduleB.Dir, "go.mod")),
+					filepath.Join("example.org", "b", "1"):                BeADirectory(),
+					filepath.Join("example.org", "b", "1", "go.mod"):      BeASymlinkTo(filepath.Join(moduleB1.Dir, "go.mod")),
+					filepath.Join("example.org", "b", "1", "1"):           BeADirectory(),
+					filepath.Join("example.org", "b", "1", "1", "go.mod"): BeASymlinkTo(filepath.Join(moduleB11.Dir, "go.mod")),
+					filepath.Join("example.org", "b", "2"):                BeADirectory(),
+					filepath.Join("example.org", "b", "2", "go.mod"):      BeASymlinkTo(filepath.Join(moduleB2.Dir, "go.mod")),
+				}))
+			})
+		})
+
 		Describe("GoBin", func() {
 			var (
 				srcGoBinDir string
@@ -190,6 +224,73 @@ var _ = Describe("Internal", func() {
 	})
 })
 
+func makeModules(gopath string, mods ...*module.Module) error {
+	for _, mod := range mods {
+		// update dir to include gopath prefix
+		mod.Dir = filepath.Join(gopath, mod.Dir)
+
+		if err := os.MkdirAll(mod.Dir, 0777); err != nil {
+			return err
+		}
+
+		if err := os.WriteFile(filepath.Join(mod.Dir, "go.mod"), []byte("module "+mod.Path+"\n"), 0666); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func HaveEntries(expected map[string]types.GomegaMatcher) types.GomegaMatcher {
+	return &haveEntriesMatcher{matchers: expected}
+}
+
+// haveEntriesMatcher is very similar to matchers.AndMatcher.
+type haveEntriesMatcher struct {
+	matchers map[string]types.GomegaMatcher
+
+	// state
+	baseDir             string
+	firstFailedFilename string
+}
+
+func (m *haveEntriesMatcher) Match(actual interface{}) (success bool, err error) {
+	m.firstFailedFilename = ""
+
+	var ok bool
+	m.baseDir, ok = actual.(string)
+	if !ok {
+		return false, fmt.Errorf("HaveEntries matcher expects a string but got %T", actual)
+	}
+
+	// sort matchers by filename for stable test results even though maps are unsorted
+	filenames := make([]string, 0, len(m.matchers))
+	for filename := range m.matchers {
+		filenames = append(filenames, filename)
+	}
+	slices.Sort(filenames)
+
+	for _, filename := range filenames {
+		matcher := m.matchers[filename]
+
+		success, err := matcher.Match(filepath.Join(m.baseDir, filename))
+		if !success || err != nil {
+			m.firstFailedFilename = filename
+			return false, err
+		}
+	}
+
+	return true, nil
+}
+
+func (m *haveEntriesMatcher) FailureMessage(actual interface{}) (message string) {
+	return m.matchers[m.firstFailedFilename].FailureMessage(filepath.Join(m.baseDir, m.firstFailedFilename))
+}
+
+func (m *haveEntriesMatcher) NegatedFailureMessage(actual interface{}) (message string) {
+	// not the most beautiful list of matchers, but not bad either...
+	return format.Message(actual, "not to have these entries: %s", m.matchers)
+}
+
 func BeASymlinkTo(filename string) types.GomegaMatcher {
 	return &beASymlinkToMatcher{filename}
 }