Resolve symlinks if project root has them.

context.go

@@ -17,7 +17,8 @@ import (
 
 // Ctx defines the supporting context of the tool.
 type Ctx struct {
-	GOPATH string // Go path
+	GOPATH  string   // Selected Go path
+	GOPATHS []string // Other Go paths
 }
 
 // NewContext creates a struct with the project's GOPATH. It assumes
@@ -26,18 +27,28 @@ func NewContext() (*Ctx, error) {
 	// this way we get the default GOPATH that was added in 1.8
 	buildContext := build.Default
 	wd, err := os.Getwd()
+
 	if err != nil {
 		return nil, errors.Wrap(err, "getting work directory")
 	}
 	wd = filepath.FromSlash(wd)
+	ctx := &Ctx{}
+
 	for _, gp := range filepath.SplitList(buildContext.GOPATH) {
 		gp = filepath.FromSlash(gp)
+
 		if filepath.HasPrefix(wd, gp) {
-			return &Ctx{GOPATH: gp}, nil
+			ctx.GOPATH = gp
 		}
+
+		ctx.GOPATHS = append(ctx.GOPATHS, gp)
 	}
 
-	return nil, errors.New("project not in a GOPATH")
+	if ctx.GOPATH == "" {
+		return nil, errors.New("project not in a GOPATH")
+	}
+
+	return ctx, nil
 }
 
 func (c *Ctx) SourceManager() (*gps.SourceMgr, error) {
@@ -74,6 +85,13 @@ func (c *Ctx) LoadProject(path string) (*Project, error) {
 		return nil, err
 	}
 
+	// The path may lie within a symlinked directory, resolve the path
+	// before moving forward
+	p.AbsRoot, err = c.resolveProjectRoot(p.AbsRoot)
+	if err != nil {
+		return nil, errors.Wrapf(err, "resolve project root")
+	}
+
 	ip, err := c.SplitAbsoluteProjectRoot(p.AbsRoot)
 	if err != nil {
 		return nil, errors.Wrap(err, "split absolute project root")
@@ -117,6 +135,43 @@ func (c *Ctx) LoadProject(path string) (*Project, error) {
 	return p, nil
 }
 
+// resolveProjectRoot evaluates the root directory and does the following:
+//
+// If the passed path is a symlink outside GOPATH to a directory within a
+// GOPATH, the resolved full real path is returned.
+//
+// If the passed path is a symlink within a GOPATH, we return an error.
+//
+// If the passed path isn't a symlink at all, we just pass through.
+func (c *Ctx) resolveProjectRoot(path string) (string, error) {
+	// Determine if this path is a Symlink
+	l, err := os.Lstat(path)
+	if err != nil {
+		return "", errors.Wrap(err, "resolveProjectRoot")
+	}
+
+	// Pass through if not
+	if l.Mode()&os.ModeSymlink == 0 {
+		return path, nil
+	}
+
+	// Resolve path
+	resolved, err := filepath.EvalSymlinks(path)
+	if err != nil {
+		return "", errors.Wrap(err, "resolveProjectRoot")
+	}
+
+	// Determine if the symlink is within any of the GOPATHs, in which case we're not
+	// sure how to resolve it.
+	for _, gp := range c.GOPATHS {
+		if filepath.HasPrefix(path, gp) {
+			return "", errors.Errorf("'%s' is linked to another path within a GOPATH (%s)", path, gp)
+		}
+	}
+
+	return resolved, nil
+}
+
 // SplitAbsoluteProjectRoot takes an absolute path and compares it against declared
 // GOPATH(s) to determine what portion of the input path should be treated as an
 // import path - as a project root.

context_test.go

@@ -38,6 +38,7 @@ func TestSplitAbsoluteProjectRoot(t *testing.T) {
 	defer h.Cleanup()
 
 	h.TempDir("src")
+
 	h.Setenv("GOPATH", h.Path("."))
 	depCtx := &Ctx{GOPATH: h.Path(".")}
 
@@ -346,3 +347,74 @@ func TestCaseInsentitiveGOPATH(t *testing.T) {
 		t.Fatalf("expected %s, got %s", ip, pr)
 	}
 }
+
+func TestResolveProjectRoot(t *testing.T) {
+	tg := test.NewHelper(t)
+	defer tg.Cleanup()
+
+	tg.TempDir("go")
+	tg.TempDir("go/src")
+	tg.TempDir("go/src/real")
+	tg.TempDir("go/src/real/path")
+	tg.TempDir("go/src/sym")
+
+	tg.TempDir("gotwo") // Another directory used as a GOPATH
+	tg.TempDir("gotwo/src")
+	tg.TempDir("gotwo/src/real")
+	tg.TempDir("gotwo/src/real/path")
+	tg.TempDir("gotwo/src/sym")
+
+	tg.TempDir("sym") // Directory for symlinks
+
+	tg.Setenv("GOPATH", tg.Path(filepath.Join(".", "go")))
+
+	ctx := &Ctx{
+		GOPATH: tg.Path(filepath.Join(".", "go")),
+		GOPATHS: []string{
+			tg.Path(filepath.Join(".", "go")),
+			tg.Path(filepath.Join(".", "gotwo")),
+		},
+	}
+
+	realPath := filepath.Join(ctx.GOPATH, "src", "real", "path")
+	realPathTwo := filepath.Join(ctx.GOPATHS[1], "src", "real", "path")
+	symlinkedPath := filepath.Join(tg.Path("."), "sym", "symlink")
+	symlinkedInGoPath := filepath.Join(ctx.GOPATH, "src/sym/path")
+	symlinkedInOtherGoPath := filepath.Join(tg.Path("."), "sym", "symtwo")
+	os.Symlink(realPath, symlinkedPath)
+	os.Symlink(realPath, symlinkedInGoPath)
+	os.Symlink(realPathTwo, symlinkedInOtherGoPath)
+
+	// Real path should be returned, no symlinks to deal with
+	p, err := ctx.resolveProjectRoot(realPath)
+	if err != nil {
+		t.Fatalf("Error resolving project root: %s", err)
+	}
+	if p != realPath {
+		t.Fatalf("Want path to be %s, got %s", realPath, p)
+	}
+
+	// Real path should be returned, symlink is outside GOPATH
+	p, err = ctx.resolveProjectRoot(symlinkedPath)
+	if err != nil {
+		t.Fatalf("Error resolving project root: %s", err)
+	}
+	if p != realPath {
+		t.Fatalf("Want path to be %s, got %s", realPath, p)
+	}
+
+	// Real path should be returned, symlink is in another GOPATH
+	p, err = ctx.resolveProjectRoot(symlinkedInOtherGoPath)
+	if err != nil {
+		t.Fatalf("Error resolving project root: %s", err)
+	}
+	if p != realPathTwo {
+		t.Fatalf("Want path to be %s, got %s", realPathTwo, p)
+	}
+
+	// Symlinked path is inside GOPATH, should return error
+	_, err = ctx.resolveProjectRoot(symlinkedInGoPath)
+	if err == nil {
+		t.Fatalf("Wanted an error")
+	}
+}