Other: add straightforward linters

internal/transfer/mailbox.go

@@ -35,7 +35,7 @@ var systemFolderMapping = map[string]string{ //nolint[gochecknoglobals]
 	// Add more translations.
 }
 
-// LeastUsedColor is intended to return color for creating a new inbox or label
+// LeastUsedColor is intended to return color for creating a new inbox or label.
 func LeastUsedColor(mailboxes []Mailbox) string {
 	usedColors := []string{}
 	for _, m := range mailboxes {

internal/transfer/provider_imap.go

@@ -27,7 +27,7 @@ import (
 
 type IMAPClientProvider interface {
 	Capability() (map[string]bool, error)
-	Support(cap string) (bool, error)
+	Support(capability string) (bool, error)
 	State() imap.ConnState
 	SupportAuth(mech string) (bool, error)
 	Authenticate(auth sasl.Client) error

internal/transfer/provider_pmapi_target.go

@@ -329,10 +329,10 @@ func (p *PMAPIProvider) importMessage(msgSourceID string, progress *Progress, re
 		}
 		if results[0].Error != nil {
 			importedErr = errors.Wrap(results[0].Error, "failed to import message")
-			return nil // Call passed but API refused this message, skip this one.
+			return nil //nolint[nilerr] Call passed but API refused this message, skip this one.
 		}
 		importedID = results[0].MessageID
 		return nil
 	})
-	return
+	return importedID, importedErr
 }

internal/transfer/provider_test.go

@@ -85,7 +85,7 @@ func testTransferFrom(t *testing.T, rules transferRules, provider TargetProvider
 		progress.finish()
 	}()
 
-	maxWait := time.Duration(len(messages)) * 2 * time.Second
+	maxWait := time.Duration(len(messages)*2) * time.Second
 	a.Eventually(t, func() bool {
 		return progress.updateCh == nil
 	}, maxWait, 10*time.Millisecond, "Waiting for imported messages timed out")