feat: add Composer lock file handling and testing

This commit introduces functionality to read and parse the composer.lock file, encapsulated in the new `ReadComposerLock` function. It also adds a comprehensive test suite for this functionality, ensuring correct behavior for valid, non-existent, and invalid JSON files. Additionally, a new rules file is created to enforce coding standards and practices.

Author: shyim

.cursor/rules/repository.mdc

@@ -0,0 +1,17 @@
+---
+description: 
+globs: 
+alwaysApply: true
+---
+# General rules
+
+- Use convential commit messages
+- Use always Go 1.24 syntax, use slices package for slice containing
+- Inline error into if condition like this:
+
+```go
+if err := foo(); err != nil {
+    // something
+}
+```
+

extension/project.go

@@ -10,6 +10,7 @@ import (
 	"regexp"
 	"strings"
 
+	"github.com/shopware/shopware-cli/internal/packagist"
 	"github.com/shopware/shopware-cli/internal/phpexec"
 
 	"github.com/shopware/shopware-cli/shop"
@@ -45,17 +46,13 @@ func GetShopwareProjectConstraint(project string) (*version.Constraints, error)
 	c, err := version.NewConstraint(constraint)
 	if err != nil {
 		if strings.Contains(err.Error(), "malformed constraint") {
-			var lock composerLock
-
-			lockFile, readErr := os.ReadFile(path.Join(project, "composer.lock"))
-
-			if readErr != nil {
-				// popup real error
+			if _, statErr := os.Stat(path.Join(project, "composer.lock")); os.IsNotExist(statErr) {
 				return nil, err
 			}
 
-			if err := json.Unmarshal(lockFile, &lock); err != nil {
-				return nil, fmt.Errorf("could not parse composer.lock: %w", err)
+			lock, err := packagist.ReadComposerLock(path.Join(project, "composer.lock"))
+			if err != nil {
+				return nil, err
 			}
 
 			for _, pkg := range lock.Packages {

internal/packagist/lock.go

@@ -0,0 +1,29 @@
+package packagist
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+)
+
+type ComposerLock struct {
+	Packages []struct {
+		Name        string `json:"name"`
+		Version     string `json:"version"`
+		PackageType string `json:"type"`
+	} `json:"packages"`
+}
+
+func ReadComposerLock(pathToFile string) (*ComposerLock, error) {
+	content, err := os.ReadFile(pathToFile)
+	if err != nil {
+		return nil, err
+	}
+
+	var lock ComposerLock
+	if err := json.Unmarshal(content, &lock); err != nil {
+		return nil, fmt.Errorf("could not parse composer.lock: %w", err)
+	}
+
+	return &lock, nil
+}

internal/packagist/lock_test.go

@@ -0,0 +1,55 @@
+package packagist
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReadComposerLock(t *testing.T) {
+	t.Run("valid composer.lock", func(t *testing.T) {
+		// Create a temporary composer.lock file
+		dir := t.TempDir()
+		lockFile := filepath.Join(dir, "composer.lock")
+		content := `{
+			"packages": [
+				{
+					"name": "symfony/console",
+					"version": "v6.3.0",
+					"type": "library"
+				}
+			]
+		}`
+		err := os.WriteFile(lockFile, []byte(content), 0644)
+		assert.NoError(t, err)
+
+		// Test reading the file
+		lock, err := ReadComposerLock(lockFile)
+		assert.NoError(t, err)
+		assert.NotNil(t, lock)
+		assert.Len(t, lock.Packages, 1)
+		assert.Equal(t, "symfony/console", lock.Packages[0].Name)
+		assert.Equal(t, "v6.3.0", lock.Packages[0].Version)
+		assert.Equal(t, "library", lock.Packages[0].PackageType)
+	})
+
+	t.Run("non-existent file", func(t *testing.T) {
+		lock, err := ReadComposerLock("non-existent-file.lock")
+		assert.Error(t, err)
+		assert.Nil(t, lock)
+	})
+
+	t.Run("invalid JSON", func(t *testing.T) {
+		// Create a temporary file with invalid JSON
+		dir := t.TempDir()
+		lockFile := filepath.Join(dir, "invalid.lock")
+		err := os.WriteFile(lockFile, []byte("invalid json"), 0644)
+		assert.NoError(t, err)
+
+		lock, err := ReadComposerLock(lockFile)
+		assert.Error(t, err)
+		assert.Nil(t, lock)
+	})
+}