Rework LocalModule based on review comments

Signed-off-by: Petr Korobeinikov <pkorobeinikov@gmail.com>

pkg/gci/gci_test.go

@@ -21,10 +21,6 @@ func init() {
 }
 
 func TestRun(t *testing.T) {
-	// if runtime.GOOS == "windows" {
-	// 	t.Skip("Skipping test on Windows")
-	// }
-
 	for i := range testCases {
 		t.Run(fmt.Sprintf("run case: %s", testCases[i].name), func(t *testing.T) {
 			config, err := config.ParseConfig(testCases[i].config)
@@ -56,10 +52,10 @@ func chdir(t *testing.T, dir string) {
 func readConfig(t *testing.T, configPath string) *config.Config {
 	rawConfig, err := os.ReadFile(configPath)
 	require.NoError(t, err)
-	config, err := config.ParseConfig(string(rawConfig))
+	cfg, err := config.ParseConfig(string(rawConfig))
 	require.NoError(t, err)
 
-	return config
+	return cfg
 }
 
 func TestRunWithLocalModule(t *testing.T) {
@@ -126,20 +122,5 @@ func TestRunWithLocalModuleWithPackageLoadFailure(t *testing.T) {
 
 	chdir(t, dir)
 	_, err := config.ParseConfig(configContent)
-	require.ErrorContains(t, err, "failed to load local modules: ")
-}
-
-func TestRunWithLocalModuleWithModuleLookupError(t *testing.T) {
-	t.Skipf("In fact there is no error when no go files found in the project root")
-
-	dir := t.TempDir()
-	// error from trying to list packages under module with no go files
-	configContent := "sections:\n  - LocalModule\n"
-	goModContent := "module example.com/foo\n"
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "go.mod"), []byte(goModContent), 0o644))
-
-	chdir(t, dir)
-	_, err := config.ParseConfig(configContent)
-	require.ErrorContains(t, err, "error reading local packages: ")
-	require.ErrorContains(t, err, dir)
+	require.ErrorContains(t, err, "go.mod: open go.mod: no such file or directory")
 }

pkg/gci/testdata.go

@@ -1293,29 +1293,6 @@ import (
 	"fmt"
 	"net"
 )
-`,
-	},
-	{
-		"basic module",
-		// implicitly relies on the local module name being: github.com/daixiang0/gci
-		`sections:
-  - Standard
-  - LocalModule
-`,
-		`package main
-
-import (
-	"os"
-	"github.com/daixiang0/gci/cmd/gci"
-)
-`,
-		`package main
-
-import (
-	"os"
-
-	"github.com/daixiang0/gci/cmd/gci"
-)
 `,
 	},
 }

pkg/section/local_module.go

@@ -6,7 +6,6 @@ import (
 	"strings"
 
 	"golang.org/x/mod/modfile"
-	"golang.org/x/tools/go/packages"
 
 	"github.com/daixiang0/gci/pkg/parse"
 	"github.com/daixiang0/gci/pkg/specificity"
@@ -15,15 +14,12 @@ import (
 const LocalModuleType = "localmodule"
 
 type LocalModule struct {
-	Paths []string
+	Path string
 }
 
 func (m *LocalModule) MatchSpecificity(spec *parse.GciImports) specificity.MatchSpecificity {
-	for _, modPath := range m.Paths {
-		// also check path etc.
-		if strings.HasPrefix(spec.Path, modPath) {
-			return specificity.LocalModule{}
-		}
+	if strings.HasPrefix(spec.Path, m.Path) {
+		return specificity.LocalModule{}
 	}
 
 	return specificity.MisMatch{}
@@ -40,59 +36,21 @@ func (m *LocalModule) Type() string {
 // Configure configures the module section by finding the module
 // for the current path
 func (m *LocalModule) Configure() error {
-	modPaths, err := findLocalModules()
+	modPath, err := findLocalModule()
 	if err != nil {
 		return err
 	}
-	m.Paths = modPaths
-	return nil
-}
-
-func findLocalModules() ([]string, error) {
-	pkgs, err := packages.Load(
-		// find the package in the current dir and load its module
-		// NeedFiles so there is some more info in package errors
-		&packages.Config{Mode: packages.NeedModule | packages.NeedFiles},
-		".",
-	)
-	if err != nil {
-		return nil, fmt.Errorf("failed to load local modules: %v", err)
-	}
-
-	uniqueModules := make(map[string]struct{})
-
-	for _, pkg := range pkgs {
-		if len(pkg.Errors) != 0 && !errorsContainListError(pkg.Errors) {
-			return nil, fmt.Errorf("error reading local packages: %v", pkg.Errors)
-		}
-		if pkg.Module != nil {
-			uniqueModules[pkg.Module.Path] = struct{}{}
-		} else {
-			b, err := os.ReadFile("go.mod")
-			if err != nil {
-				return nil, fmt.Errorf("failed to read go.mod file directly: %v", err)
-			}
 
-			name := modfile.ModulePath(b)
-			uniqueModules[name] = struct{}{}
+	m.Path = modPath
 
-		}
-	}
-
-	modPaths := make([]string, 0, len(uniqueModules))
-	for mod := range uniqueModules {
-		modPaths = append(modPaths, mod)
-	}
-
-	return modPaths, nil
+	return nil
 }
 
-func errorsContainListError(errors []packages.Error) bool {
-	for _, v := range errors {
-		if v.Kind == packages.ListError {
-			return true
-		}
+func findLocalModule() (string, error) {
+	b, err := os.ReadFile("go.mod")
+	if err != nil {
+		return "", fmt.Errorf("go.mod: %w", err)
 	}
 
-	return false
+	return modfile.ModulePath(b), nil
 }