wrappers: skip snapd desktop files in {Ensure,Remove}SnapDesktopFiles (…

…canonical#14468)

Snapd desktop files on core are installed under SnapDesktopFilesDir
and since they don't have the usual X-SnapInstanceName for other snaps
errors were showing in the logs.

This just skips those files when looking up installed desktop files.

Signed-off-by: Zeyad Gouda <[email protected]>

wrappers/core18.go

@@ -701,6 +701,15 @@ var snapdDesktopFileNames = []string{
 	"snap-handle-link.desktop",
 }
 
+func isSnapdDesktopFile(desktopFile string) bool {
+	for _, df := range snapdDesktopFileNames {
+		if desktopFile == df {
+			return true
+		}
+	}
+	return false
+}
+
 func writeSnapdDesktopFilesOnCore(s *snap.Info) error {
 	// Ensure /var/lib/snapd/desktop/applications exists
 	if err := os.MkdirAll(dirs.SnapDesktopFilesDir, 0755); err != nil {

wrappers/desktop.go

@@ -282,23 +282,29 @@ func deriveDesktopFilesContent(s *snap.Info) (map[string]osutil.FileState, error
 // forAllDesktopFiles loops over all installed desktop files under
 // dirs.SnapDesktopFilesDir.
 //
-// Only the desktop file base and parsed instance name is passed the callback
-// function.
+// Only the desktop file base and parsed instance name are passed to the
+// callback function.
 func forAllDesktopFiles(cb func(base, instanceName string) error) error {
 	installedDesktopFiles, err := findDesktopFiles(dirs.SnapDesktopFilesDir)
 	if err != nil {
 		return err
 	}
 
 	for _, desktopFile := range installedDesktopFiles {
+		base := filepath.Base(desktopFile)
+		if isSnapdDesktopFile(base) {
+			// skip snapd desktop files installed on core, they don't
+			// have the usual X-SnapInstanceName entry.
+			continue
+		}
+
 		de, err := desktopentry.Read(desktopFile)
 		if err != nil || de.SnapInstanceName == "" {
 			// cannot read instance name from desktop file, ignore
 			logger.Noticef("cannot read instance name: %s", err)
 			continue
 		}
 
-		base := filepath.Base(desktopFile)
 		if err := cb(base, de.SnapInstanceName); err != nil {
 			return err
 		}

wrappers/desktop_test.go

@@ -835,3 +835,29 @@ func (s *desktopSuite) TestAddRemoveDesktopFiles(c *C) {
 		c.Assert(osutil.FileExists(expectedDesktopFilePath), Equals, false)
 	}
 }
+
+func (s *desktopSuite) TestForAllDesktopFilesSkipsSnapdDesktopFiles(c *C) {
+	c.Assert(os.MkdirAll(dirs.SnapDesktopFilesDir, 0755), IsNil)
+
+	var mockDesktopFile = []byte(`
+[Desktop Entry]
+Name=foo
+X-SnapInstanceName=foo`)
+
+	desktopFiles := wrappers.SnapdDesktopFileNames
+	desktopFiles = append(desktopFiles, "foo_foo.desktop", "foo_bar.desktop")
+	for _, df := range desktopFiles {
+		c.Assert(os.WriteFile(filepath.Join(dirs.SnapDesktopFilesDir, df), mockDesktopFile, 0644), IsNil)
+	}
+
+	found := make(map[string]string, 2)
+	err := wrappers.ForAllDesktopFiles(func(base, instanceName string) error {
+		found[base] = instanceName
+		return nil
+	})
+	c.Assert(err, IsNil)
+
+	c.Check(found, HasLen, 2)
+	c.Check(found["foo_foo.desktop"], Equals, "foo")
+	c.Check(found["foo_bar.desktop"], Equals, "foo")
+}

wrappers/export_test.go

@@ -35,6 +35,8 @@ var (
 	DetectAppAndRewriteExecLine = detectAppAndRewriteExecLine
 	RewriteIconLine             = rewriteIconLine
 	IsValidDesktopFileLine      = isValidDesktopFileLine
+	ForAllDesktopFiles          = forAllDesktopFiles
+	SnapdDesktopFileNames       = snapdDesktopFileNames
 
 	// daemons
 	NewUserServiceClientNames = newUserServiceClientNames