#1151: Fix error with InterfaceDirRelative for external paths (#1157)

* #1151: Fix error with InterfaceDirRelative for external paths

---------

Co-authored-by: LandonTClipp <11232769+LandonTClipp@users.noreply.github.com>

Author: takanuva15

.mockery_testify.yml

@@ -151,4 +151,8 @@ packages:
           # The second option asserts that the value itself is sane. https://github.com/vektra/mockery/issues/1133#issuecomment-3758283921
           # This mock will be explicitly tested against so that we can assert in tests that the value
           # does not encounter breaking changes.
-          - dir: '{{.InterfaceDir}}/{{.InterfaceDirRelative}}'
+          - dir: '{{.InterfaceDir}}/{{.InterfaceDirRelative}}'
+  github.com/LandonTClipp/example-go-repo:
+    config:
+      all: True
+      recursive: True

config/config.go

@@ -30,6 +30,7 @@ import (
 	"github.com/rs/zerolog"
 	"github.com/spf13/pflag"
 	internalConfig "github.com/vektra/mockery/v3/internal/config"
+	internalFile "github.com/vektra/mockery/v3/internal/file"
 	"github.com/vektra/mockery/v3/internal/logging"
 	"github.com/vektra/mockery/v3/internal/stackerr"
 	"github.com/vektra/mockery/v3/template_funcs"
@@ -775,24 +776,39 @@ func (c *Config) buildTemplateData(
 	interfaceDirPath := filepath.ToSlash(filepath.Dir(ifaceFilePath))
 
 	var interfaceDirRelative string
-	interfaceDirRelativePath, err := filepath.Rel(filepath.FromSlash(workingDir), filepath.FromSlash(interfaceDirPath))
+	outsideCurrentRepo, err := isPathOutsideCurrentGoModRepo(workingDir, interfaceDirPath)
 	if err != nil {
 		log.Debug().
 			Err(err).
-			Str("working-dir", workingDir).
-			Str("interfaceDirPath", interfaceDirPath).
-			Str("interface-dir-relative-path", interfaceDirRelativePath).
-			Str("iface-file-path", ifaceFilePath).
-			Msg("can't make path relative to working dir, setting to './'")
-		interfaceDirRelative = "."
-	} else {
-		interfaceDirRelativePath = filepath.ToSlash(interfaceDirRelativePath)
+			Msg("failed to determine whether interface path is outside current go.mod repo")
+	}
+	if outsideCurrentRepo {
 		log.Debug().
 			Str("working-dir", workingDir).
 			Str("interfaceDirPath", interfaceDirPath).
-			Str("interface-dir-relative-path", interfaceDirRelativePath).
-			Msg("found relative path")
-		interfaceDirRelative = interfaceDirRelativePath
+			Str("src-package-path", srcPkg.Types.Path()).
+			Msg("interface path is outside current go.mod repo; using fully-qualified package path")
+		interfaceDirRelative = srcPkg.Types.Path()
+	} else {
+		interfaceDirRelativePath, err := filepath.Rel(filepath.FromSlash(workingDir), filepath.FromSlash(interfaceDirPath))
+		if err != nil {
+			log.Debug().
+				Err(err).
+				Str("working-dir", workingDir).
+				Str("interfaceDirPath", interfaceDirPath).
+				Str("interface-dir-relative-path", interfaceDirRelativePath).
+				Str("iface-file-path", ifaceFilePath).
+				Msg("can't make path relative to working dir, setting to './'")
+			interfaceDirRelative = "."
+		} else {
+			interfaceDirRelativePath = filepath.ToSlash(interfaceDirRelativePath)
+			log.Debug().
+				Str("working-dir", workingDir).
+				Str("interfaceDirPath", interfaceDirPath).
+				Str("interface-dir-relative-path", interfaceDirRelativePath).
+				Msg("found relative path")
+			interfaceDirRelative = interfaceDirRelativePath
+		}
 	}
 
 	return TemplateData{
@@ -809,6 +825,27 @@ func (c *Config) buildTemplateData(
 	}, nil
 }
 
+func isPathOutsideCurrentGoModRepo(workingDir string, targetPath string) (bool, error) {
+	goModFile, _, err := internalFile.FindInHierarchy(workingDir, []string{"go.mod"})
+	if err != nil {
+		return false, err
+	}
+
+	repoRoot := filepath.ToSlash(filepath.Dir(goModFile))
+	targetPath = filepath.ToSlash(filepath.Clean(targetPath))
+
+	relFromRepoRoot, err := filepath.Rel(filepath.FromSlash(repoRoot), filepath.FromSlash(targetPath))
+	// Windows can return an error here if the paths are on different drives.
+	// In that case, we can just assume the target path is outside the repo.
+	if err != nil {
+		//nolint:nilerr // Intentional: treat cross-drive Rel errors as "outside repo", not a fatal error.
+		return true, nil
+	}
+	relFromRepoRoot = filepath.ToSlash(relFromRepoRoot)
+
+	return relFromRepoRoot == ".." || strings.HasPrefix(relFromRepoRoot, "../"), nil
+}
+
 func (c *Config) GetReplacement(pkgPath string, typeName string) *ReplaceType {
 	pkgMap := c.ReplaceType[pkgPath]
 	if pkgMap == nil {

config/config_test.go

@@ -243,3 +243,50 @@ func TestBuildTemplateData(t *testing.T) {
 	assert.Equal(t, "github.com/test/pkg", data.SrcPackagePath)
 	assert.Equal(t, "my-template", data.Template)
 }
+
+func TestBuildTemplateData_InterfaceDirRelativeUsesPackagePathOutsideRepo(t *testing.T) {
+	ctx := context.Background()
+
+	configFile := "/config/config.yaml"
+	structName := "MyStruct"
+	templateName := "my-template"
+
+	c := &Config{
+		ConfigFile: &configFile,
+		StructName: &structName,
+		Template:   &templateName,
+	}
+
+	pkg := &packages.Package{
+		Types: types.NewPackage("github.com/test/module/subpkg", "mypkg"),
+	}
+
+	ifacePath := filepath.ToSlash(filepath.Join(os.TempDir(), "mockery-external-module", "foo", "bar.go"))
+	expectedInterfaceDir := filepath.ToSlash(filepath.Dir(ifacePath))
+
+	data, err := c.buildTemplateData(
+		ctx,
+		ifacePath,
+		"API",
+		pkg,
+	)
+	require.NoError(t, err)
+
+	assert.Equal(t, expectedInterfaceDir, data.InterfaceDir)
+	assert.Equal(t, "github.com/test/module/subpkg", data.InterfaceDirRelative)
+}
+
+func TestIsPathOutsideCurrentGoModRepo(t *testing.T) {
+	wd, err := os.Getwd()
+	require.NoError(t, err)
+
+	outsidePath := filepath.ToSlash(filepath.Join(os.TempDir(), "mockery-outside-repo", "foo"))
+	outsideRepo, err := isPathOutsideCurrentGoModRepo(wd, outsidePath)
+	require.NoError(t, err)
+	assert.True(t, outsideRepo)
+
+	insidePath := filepath.ToSlash(filepath.Join(wd, "config"))
+	insideRepo, err := isPathOutsideCurrentGoModRepo(wd, insidePath)
+	require.NoError(t, err)
+	assert.False(t, insideRepo)
+}

github.com/LandonTClipp/example-go-repo/main_test.go

@@ -0,0 +1,11 @@
+package foo
+
+import "testing"
+
+func TestFoo(t *testing.T) {
+	m := NewMockFoo(t)
+	m.EXPECT().Bar("hello").Return(42)
+	if got := m.Bar("hello"); got != 42 {
+		t.Errorf("Bar() = %v, want %v", got, 42)
+	}
+}

github.com/LandonTClipp/example-go-repo/mocks_testify_foo_test.go

@@ -1,8 +1,9 @@
 module github.com/vektra/mockery/v3
 
-go 1.25.0
+go 1.25.5
 
 require (
+	github.com/LandonTClipp/example-go-repo v0.1.2
 	github.com/brunoga/deep v1.3.1
 	github.com/go-viper/mapstructure/v2 v2.5.0
 	github.com/huandu/xstrings v1.5.0

go.mod

@@ -1,3 +1,5 @@
+github.com/LandonTClipp/example-go-repo v0.1.2 h1:R4kP4EcCPuRy4l8iV8Bt1fZwLfbG7kZv7FEn+c7HxME=
+github.com/LandonTClipp/example-go-repo v0.1.2/go.mod h1:aKxggDcybo4AWkfCrBXcgBGqAxP+G+KT4OULG0bTQvQ=
 github.com/brunoga/deep v1.3.1 h1:bSrL6FhAZa6JlVv4vsi7Hg8SLwroDb1kgDERRVipBCo=
 github.com/brunoga/deep v1.3.1/go.mod h1:GDV6dnXqn80ezsLSZ5Wlv1PdKAWAO4L5PnKYtv2dgaI=
 github.com/clipperhouse/uax29/v2 v2.2.0 h1:ChwIKnQN3kcZteTXMgb1wztSgaU+ZemkgWdohwgs8tY=

go.sum

@@ -1,4 +1,4 @@
-go 1.25.0
+go 1.25.5
 
 use (
 	.