util: add flatpak introspection utilities

.github/workflows/go-ci.yml

@@ -28,6 +28,15 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Install flatpak
+        run: sudo apt update && sudo apt install -y flatpak
+
+      - name: Add flathub
+        run: sudo flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
+
+      - name: Add a flatpak that mutagen could support
+        run: sudo flatpak install -y org.freedesktop.Platform/x86_64/24.08 app.zen_browser.zen
+
       - name: Set up Go
         uses: actions/setup-go@v5
         with:

core/internal/utils/flatpak.go

@@ -0,0 +1,78 @@
+package utils
+
+import (
+	"bytes"
+	"errors"
+	"os/exec"
+	"strings"
+)
+
+func FlatpakInPath() bool {
+	_, err := exec.LookPath("flatpak")
+	return err == nil
+}
+
+func FlatpakExists(name string) bool {
+	if !FlatpakInPath() {
+		return false
+	}
+
+	cmd := exec.Command("flatpak", "info", name)
+	err := cmd.Run()
+	return err == nil
+}
+
+func FlatpakSearchBySubstring(substring string) bool {
+	if !FlatpakInPath() {
+		return false
+	}
+
+	cmd := exec.Command("flatpak", "list", "--app")
+	var stdout bytes.Buffer
+	cmd.Stdout = &stdout
+
+	if err := cmd.Run(); err != nil {
+		return false
+	}
+
+	out := stdout.String()
+
+	for line := range strings.SplitSeq(out, "\n") {
+		fields := strings.Fields(line)
+		if len(fields) > 1 {
+			id := fields[1]
+			idParts := strings.Split(id, ".")
+			// We are assuming that the last part of the ID is
+			// the package name we're looking for. This might
+			// not always be true, some developers use arbitrary
+			// suffixes.
+			if len(idParts) > 0 && idParts[len(idParts)-1] == substring {
+				cmd := exec.Command("flatpak", "info", id)
+				err := cmd.Run()
+				return err == nil
+			}
+		}
+	}
+	return false
+}
+
+func FlatpakInstallationDir(name string) (string, error) {
+	if !FlatpakInPath() {
+		return "", errors.New("flatpak not found in PATH")
+	}
+
+	cmd := exec.Command("flatpak", "info", "--show-location", name)
+	var stdout bytes.Buffer
+	cmd.Stdout = &stdout
+
+	if err := cmd.Run(); err != nil {
+		return "", errors.New("flatpak not installed: " + name)
+	}
+
+	location := strings.TrimSpace(stdout.String())
+	if location == "" {
+		return "", errors.New("installation directory not found for: " + name)
+	}
+
+	return location, nil
+}

core/internal/utils/flatpak_test.go

@@ -0,0 +1,210 @@
+package utils
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestFlatpakInPathAvailable(t *testing.T) {
+	result := FlatpakInPath()
+	if !result {
+		t.Skip("flatpak not in PATH")
+	}
+	if !result {
+		t.Errorf("expected true when flatpak is in PATH")
+	}
+}
+
+func TestFlatpakInPathUnavailable(t *testing.T) {
+	tempDir := t.TempDir()
+	t.Setenv("PATH", tempDir)
+
+	result := FlatpakInPath()
+	if result {
+		t.Errorf("expected false when flatpak not in PATH, got true")
+	}
+}
+
+func TestFlatpakExistsValidPackage(t *testing.T) {
+	if !FlatpakInPath() {
+		t.Skip("flatpak not in PATH")
+	}
+
+	result := FlatpakExists("com.nonexistent.package.test")
+	if result {
+		t.Logf("package exists (unexpected but not an error)")
+	}
+}
+
+func TestFlatpakExistsNoFlatpak(t *testing.T) {
+	tempDir := t.TempDir()
+	t.Setenv("PATH", tempDir)
+
+	result := FlatpakExists("any.package.name")
+	if result {
+		t.Errorf("expected false when flatpak not in PATH, got true")
+	}
+}
+
+func TestFlatpakSearchBySubstringNoFlatpak(t *testing.T) {
+	tempDir := t.TempDir()
+	t.Setenv("PATH", tempDir)
+
+	result := FlatpakSearchBySubstring("test")
+	if result {
+		t.Errorf("expected false when flatpak not in PATH, got true")
+	}
+}
+
+func TestFlatpakSearchBySubstringNonexistent(t *testing.T) {
+	if !FlatpakInPath() {
+		t.Skip("flatpak not in PATH")
+	}
+
+	result := FlatpakSearchBySubstring("ThisIsAVeryUnlikelyPackageName12345")
+	if result {
+		t.Errorf("expected false for nonexistent package substring")
+	}
+}
+
+func TestFlatpakInstallationDirNoFlatpak(t *testing.T) {
+	tempDir := t.TempDir()
+	t.Setenv("PATH", tempDir)
+
+	_, err := FlatpakInstallationDir("any.package.name")
+	if err == nil {
+		t.Errorf("expected error when flatpak not in PATH")
+	}
+	if err != nil && !strings.Contains(err.Error(), "not found in PATH") {
+		t.Errorf("expected 'not found in PATH' error, got: %v", err)
+	}
+}
+
+func TestFlatpakInstallationDirNonexistent(t *testing.T) {
+	if !FlatpakInPath() {
+		t.Skip("flatpak not in PATH")
+	}
+
+	_, err := FlatpakInstallationDir("com.nonexistent.package.test")
+	if err == nil {
+		t.Errorf("expected error for nonexistent package")
+	}
+	if err != nil && !strings.Contains(err.Error(), "not installed") {
+		t.Errorf("expected 'not installed' error, got: %v", err)
+	}
+}
+
+func TestFlatpakInstallationDirValid(t *testing.T) {
+	if !FlatpakInPath() {
+		t.Skip("flatpak not in PATH")
+	}
+
+	// This test requires a known installed flatpak
+	// We can't guarantee any specific flatpak is installed,
+	// so we'll skip if we can't find a common one
+	commonFlatpaks := []string{
+		"org.mozilla.firefox",
+		"org.gnome.Calculator",
+		"org.freedesktop.Platform",
+	}
+
+	var testPackage string
+	for _, pkg := range commonFlatpaks {
+		if FlatpakExists(pkg) {
+			testPackage = pkg
+			break
+		}
+	}
+
+	if testPackage == "" {
+		t.Skip("no common flatpak packages found for testing")
+	}
+
+	result, err := FlatpakInstallationDir(testPackage)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if result == "" {
+		t.Errorf("expected non-empty installation directory")
+	}
+	if !strings.Contains(result, testPackage) {
+		t.Logf("installation directory %s doesn't contain package name (may be expected)", result)
+	}
+}
+
+func TestFlatpakExistsCommandFailure(t *testing.T) {
+	if !FlatpakInPath() {
+		t.Skip("flatpak not in PATH")
+	}
+
+	// Mock a failing flatpak command through PATH interception
+	tempDir := t.TempDir()
+	fakeFlatpak := filepath.Join(tempDir, "flatpak")
+
+	script := "#!/bin/sh\nexit 1\n"
+	err := os.WriteFile(fakeFlatpak, []byte(script), 0755)
+	if err != nil {
+		t.Fatalf("failed to create fake flatpak: %v", err)
+	}
+
+	originalPath := os.Getenv("PATH")
+	t.Setenv("PATH", tempDir+":"+originalPath)
+
+	result := FlatpakExists("test.package")
+	if result {
+		t.Errorf("expected false when flatpak command fails, got true")
+	}
+}
+
+func TestFlatpakSearchBySubstringCommandFailure(t *testing.T) {
+	if !FlatpakInPath() {
+		t.Skip("flatpak not in PATH")
+	}
+
+	// Mock a failing flatpak command through PATH interception
+	tempDir := t.TempDir()
+	fakeFlatpak := filepath.Join(tempDir, "flatpak")
+
+	script := "#!/bin/sh\nexit 1\n"
+	err := os.WriteFile(fakeFlatpak, []byte(script), 0755)
+	if err != nil {
+		t.Fatalf("failed to create fake flatpak: %v", err)
+	}
+
+	originalPath := os.Getenv("PATH")
+	t.Setenv("PATH", tempDir+":"+originalPath)
+
+	result := FlatpakSearchBySubstring("test")
+	if result {
+		t.Errorf("expected false when flatpak command fails, got true")
+	}
+}
+
+func TestFlatpakInstallationDirCommandFailure(t *testing.T) {
+	if !FlatpakInPath() {
+		t.Skip("flatpak not in PATH")
+	}
+
+	// Mock a failing flatpak command through PATH interception
+	tempDir := t.TempDir()
+	fakeFlatpak := filepath.Join(tempDir, "flatpak")
+
+	script := "#!/bin/sh\nexit 1\n"
+	err := os.WriteFile(fakeFlatpak, []byte(script), 0755)
+	if err != nil {
+		t.Fatalf("failed to create fake flatpak: %v", err)
+	}
+
+	originalPath := os.Getenv("PATH")
+	t.Setenv("PATH", tempDir+":"+originalPath)
+
+	_, err = FlatpakInstallationDir("test.package")
+	if err == nil {
+		t.Errorf("expected error when flatpak command fails")
+	}
+	if err != nil && !strings.Contains(err.Error(), "not installed") {
+		t.Errorf("expected 'not installed' error, got: %v", err)
+	}
+}