fix(GODT-2550): Announce IMAP ID Capability

Feature was built in but never announced to the clients.

Author: LBeernaertProton

imap/capabilities.go

@@ -9,11 +9,12 @@ const (
 	UNSELECT  Capability = `UNSELECT`
 	UIDPLUS   Capability = `UIDPLUS`
 	MOVE      Capability = `MOVE`
+	ID        Capability = `ID`
 )
 
 func IsCapabilityAvailableBeforeAuth(c Capability) bool {
 	switch c {
-	case IMAP4rev1, StartTLS, IDLE:
+	case IMAP4rev1, StartTLS, IDLE, ID:
 		return true
 	case UNSELECT, UIDPLUS, MOVE:
 		return false

internal/session/handle_capability.go

@@ -16,7 +16,7 @@ func (s *Session) getCaps() []imap.Capability {
 		return s.caps
 	}
 
-	caps := []imap.Capability{}
+	var caps []imap.Capability
 	for _, c := range s.caps {
 		if imap.IsCapabilityAvailableBeforeAuth(c) {
 			caps = append(caps, c)

internal/session/session.go

@@ -110,7 +110,7 @@ func New(
 		inputCollector:     inputCollector,
 		scanner:            scanner,
 		backend:            backend,
-		caps:               []imap.Capability{imap.IMAP4rev1, imap.IDLE, imap.UNSELECT, imap.UIDPLUS, imap.MOVE},
+		caps:               []imap.Capability{imap.IMAP4rev1, imap.IDLE, imap.UNSELECT, imap.UIDPLUS, imap.MOVE, imap.ID},
 		sessionID:          sessionID,
 		eventCh:            eventCh,
 		idleBulkTime:       idleBulkTime,

tests/capability_test.go

@@ -7,14 +7,14 @@ import (
 func TestCapability(t *testing.T) {
 	runOneToOneTest(t, defaultServerOptions(t), func(c *testConnection, _ *testSession) {
 		c.C("A001 Capability")
-		c.S(`* CAPABILITY IDLE IMAP4rev1 STARTTLS`)
+		c.S(`* CAPABILITY ID IDLE IMAP4rev1 STARTTLS`)
 		c.S("A001 OK CAPABILITY")
 
 		c.C(`A002 login "user" "pass"`)
-		c.S(`A002 OK [CAPABILITY IDLE IMAP4rev1 MOVE STARTTLS UIDPLUS UNSELECT] Logged in`)
+		c.S(`A002 OK [CAPABILITY ID IDLE IMAP4rev1 MOVE STARTTLS UIDPLUS UNSELECT] Logged in`)
 
 		c.C("A003 Capability")
-		c.S(`* CAPABILITY IDLE IMAP4rev1 MOVE STARTTLS UIDPLUS UNSELECT`)
+		c.S(`* CAPABILITY ID IDLE IMAP4rev1 MOVE STARTTLS UIDPLUS UNSELECT`)
 		c.S("A003 OK CAPABILITY")
 	})
 }

tests/login_test.go

@@ -90,7 +90,7 @@ func TestLoginLiteralFailure(t *testing.T) {
 func TestLoginCapabilities(t *testing.T) {
 	runOneToOneTest(t, defaultServerOptions(t), func(c *testConnection, _ *testSession) {
 		c.C("A001 login user pass")
-		c.S(`A001 OK [CAPABILITY IDLE IMAP4rev1 MOVE STARTTLS UIDPLUS UNSELECT] Logged in`)
+		c.S(`A001 OK [CAPABILITY ID IDLE IMAP4rev1 MOVE STARTTLS UIDPLUS UNSELECT] Logged in`)
 	})
 }