fix issues reported by errcheck

Mainly type casting issues. I ignored some of them where I don't think
it can fail or when it is in tests where we would notice anyway.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

libimage/manifests/manifests_test.go

@@ -82,6 +82,7 @@ func TestSaveLoad(t *testing.T) {
 	}()
 
 	list := Create()
+	//nolint:errcheck
 	list.(listPtr).artifacts.Detached[otherListDigest] = "relative-path-names-are-messy" // set to check that this data is recorded
 	assert.NotNil(t, list, "Create() returned nil?")
 
@@ -104,6 +105,7 @@ func TestSaveLoad(t *testing.T) {
 	assert.NoError(t, err, "LoadFromImage(3)")
 	assert.NotNilf(t, list, "LoadFromImage(3)")
 
+	//nolint:errcheck
 	assert.Equal(t, list.(listPtr).artifacts.Detached[otherListDigest], "relative-path-names-are-messy") // check that this data is loaded
 }
 

libnetwork/slirp4netns/slirp4netns.go

@@ -685,6 +685,10 @@ func openSlirp4netnsPort(apiSocket, proto, hostip string, hostport, guestport ui
 	if _, err := conn.Write([]byte(fmt.Sprintf("%s\n", data))); err != nil {
 		return fmt.Errorf("cannot write to control socket %s: %w", apiSocket, err)
 	}
+	//nolint:errcheck // This cast should never fail, if it does we get a interface
+	// conversion panic and a stack trace on how we ended up here which is more
+	// valuable than returning a human friendly error test as we don't know how it
+	// happened.
 	if err := conn.(*net.UnixConn).CloseWrite(); err != nil {
 		return fmt.Errorf("cannot shutdown the socket %s: %w", apiSocket, err)
 	}

pkg/cgroups/cgroups_linux.go

@@ -843,11 +843,16 @@ func UserOwnsCurrentSystemdCgroup() (bool, error) {
 		if err != nil {
 			return false, err
 		}
+
 		s := st.Sys()
 		if s == nil {
-			return false, fmt.Errorf("stat cgroup path %s", cgroupPath)
+			return false, fmt.Errorf("stat cgroup path is nil %s", cgroupPath)
 		}
 
+		//nolint:errcheck // This cast should never fail, if it does we get a interface
+		// conversion panic and a stack trace on how we ended up here which is more
+		// valuable than returning a human friendly error test as we don't know how it
+		// happened.
 		if int(s.(*syscall.Stat_t).Uid) != uid {
 			return false, nil
 		}

pkg/chown/chown_test.go

@@ -66,9 +66,13 @@ func TestChangeHostPathOwnership(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	sys, ok := f.Sys().(*syscall.Stat_t)
+	if !ok {
+		t.Fatal("failed to cast stat to *syscall.Stat_t")
+	}
 	// Get current ownership
-	currentUID := int(f.Sys().(*syscall.Stat_t).Uid)
-	currentGID := int(f.Sys().(*syscall.Stat_t).Gid)
+	currentUID := int(sys.Uid)
+	currentGID := int(sys.Gid)
 
 	tests := []struct {
 		Path             string

pkg/chown/chown_unix.go

@@ -29,9 +29,11 @@ func ChangeHostPathOwnership(path string, recursive bool, uid, gid int) error {
 				return err
 			}
 
+			//nolint:errcheck
+			stat := f.Sys().(*syscall.Stat_t)
 			// Get current ownership
-			currentUID := int(f.Sys().(*syscall.Stat_t).Uid)
-			currentGID := int(f.Sys().(*syscall.Stat_t).Gid)
+			currentUID := int(stat.Uid)
+			currentGID := int(stat.Gid)
 
 			if uid != currentUID || gid != currentGID {
 				return os.Lchown(filePath, uid, gid)
@@ -49,9 +51,11 @@ func ChangeHostPathOwnership(path string, recursive bool, uid, gid int) error {
 			return fmt.Errorf("failed to get host path information: %w", err)
 		}
 
+		//nolint:errcheck
+		stat := f.Sys().(*syscall.Stat_t)
 		// Get current ownership
-		currentUID := int(f.Sys().(*syscall.Stat_t).Uid)
-		currentGID := int(f.Sys().(*syscall.Stat_t).Gid)
+		currentUID := int(stat.Uid)
+		currentGID := int(stat.Gid)
 
 		if uid != currentUID || gid != currentGID {
 			if err := os.Lchown(path, uid, gid); err != nil {