Add Wails project metadata reader

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

go.mod

@@ -1,3 +1,5 @@
 module github.com/leonmika/wails-release
 
-go 1.24.3
+go 1.25.0
+
+require golang.org/x/mod v0.35.0 // indirect

go.sum

@@ -0,0 +1,2 @@
+golang.org/x/mod v0.35.0 h1:Ww1D637e6Pg+Zb2KrWfHQUnH2dQRLBQyAtpr/haaJeM=
+golang.org/x/mod v0.35.0/go.mod h1:+GwiRhIInF8wPm+4AoT6L0FA1QWAad3OMdTRx4tFYlU=

internal/wails/project.go

@@ -0,0 +1,51 @@
+package wails
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"golang.org/x/mod/modfile"
+)
+
+// Project is the subset of wails.json we care about.
+type Project struct {
+	Name string `json:"name"`
+}
+
+// ReadProject parses wails.json from dir.
+func ReadProject(dir string) (*Project, error) {
+	path := filepath.Join(dir, "wails.json")
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("read %s: %w", path, err)
+	}
+	var p Project
+	if err := json.Unmarshal(b, &p); err != nil {
+		return nil, fmt.Errorf("parse %s: %w", path, err)
+	}
+	if p.Name == "" {
+		return nil, fmt.Errorf("%s: name field is empty", path)
+	}
+	return &p, nil
+}
+
+// ProjectWailsVersion returns the require'd Wails version from go.mod.
+func ProjectWailsVersion(dir string) (string, error) {
+	path := filepath.Join(dir, "go.mod")
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return "", fmt.Errorf("read %s: %w", path, err)
+	}
+	mf, err := modfile.Parse(path, b, nil)
+	if err != nil {
+		return "", fmt.Errorf("parse %s: %w", path, err)
+	}
+	for _, r := range mf.Require {
+		if r.Mod.Path == "github.com/wailsapp/wails/v2" {
+			return r.Mod.Version, nil
+		}
+	}
+	return "", fmt.Errorf("%s: no require for github.com/wailsapp/wails/v2", path)
+}

internal/wails/project_test.go

@@ -0,0 +1,41 @@
+package wails_test
+
+import (
+	"testing"
+
+	"github.com/leonmika/wails-release/internal/wails"
+)
+
+func TestReadProject_ReturnsAppName(t *testing.T) {
+	p, err := wails.ReadProject("testdata/sample")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if p.Name != "SampleApp" {
+		t.Fatalf("name: got %q want SampleApp", p.Name)
+	}
+}
+
+func TestReadProject_MissingWailsJSONErrors(t *testing.T) {
+	_, err := wails.ReadProject("testdata/missing")
+	if err == nil {
+		t.Fatal("expected error for missing wails.json")
+	}
+}
+
+func TestProjectWailsVersion_FromGoMod(t *testing.T) {
+	v, err := wails.ProjectWailsVersion("testdata/sample")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if v != "v2.11.0" {
+		t.Fatalf("got %q, want v2.11.0", v)
+	}
+}
+
+func TestProjectWailsVersion_NoWailsDependencyErrors(t *testing.T) {
+	_, err := wails.ProjectWailsVersion("testdata/no-wails")
+	if err == nil {
+		t.Fatal("expected error for project with no wails dep")
+	}
+}

internal/wails/testdata/no-wails/go.mod

@@ -0,0 +1,3 @@
+module example.com/sample
+
+go 1.22

internal/wails/testdata/sample/go.mod

@@ -0,0 +1,5 @@
+module example.com/sample
+
+go 1.22
+
+require github.com/wailsapp/wails/v2 v2.11.0

internal/wails/testdata/sample/wails.json

@@ -0,0 +1,6 @@
+{
+  "name": "SampleApp",
+  "outputfilename": "SampleApp",
+  "frontend:install": "npm install",
+  "frontend:build": "npm run build"
+}