lint fixes

.golangci.yml

@@ -4,77 +4,123 @@ run:
   issues-exit-code: 1
   tests: true
   build-tags: []
-  skip-dirs: []
+  skip-dirs:
+    - mocks
   skip-dirs-use-default: true
   skip-files: []
   modules-download-mode: readonly
-  allow-parallel-runners: false
 
 output:
   format: colored-line-number
   print-issued-lines: true
   print-linter-name: true
-  uniq-by-line: true
-  path-prefix: ""
   sort-results: true
 
 linters-settings:
+  decorder:
+    dec-order:
+      - const
+      - var
+      - type
+      - func
+  dogsled:
+    max-blank-identifiers: 3
   errcheck:
+    check-type-assertions: true
     check-blank: true
+  errchkjson:
+    report-no-exported: true
+  exhaustive:
+    check:
+      - switch
+      - map
+    default-signifies-exhaustive: true
   gocognit:
     min-complexity: 15
   nestif:
-    min-complexity: 4
+    min-complexity: 5
   gocritic:
     enabled-tags:
+      - diagnostic
+      - style
       - performance
+  gofmt:
+    simplify: true
+    rewrite-rules:
+      - pattern: 'interface{}'
+        replacement: 'any'
+      - pattern: 'a[b:len(a)]'
+        replacement: 'a[b:]'
   gofumpt:
-    lang-version: "1.18"
+    extra-rules: true
-  gosimple:
-    go: "1.18"
-    checks: [ "all" ]
   govet:
     check-shadowing: true
-    enable:
+  grouper:
-      - atomicalign
+    const-require-single-const: true
-      - shadow
+    import-require-single-import: true
+    var-require-single-var: true
   misspell:
     locale: US
-  staticcheck:
+  usestdlibvars:
-    go: "1.18"
+    time-month: true
-    checks: [ "all" ]
+    time-layout: true
-  stylecheck:
+    crypto-hash: true
-    go: "1.18"
+    default-rpc-path: true
+    os-dev-null: true
+    sql-isolation-level: true
+    tls-signature-scheme: true
+    constant-kind: true
   unparam:
     check-exported: true
-  unused:
-    go: "1.18"
-  gci:
-    sections:
-      - standard
-      - default
-      - prefix(gitlab.com/etke.cc/postmoogle)
-    section-separators:
-      - newLine
 linters:
   disable-all: false
   enable:
-    - megacheck
+    - asasalint
-    - govet
+    - asciicheck
+    - bidichk
+    - bodyclose
+    - containedctx
+    - decorder
+    - dogsled
+    - dupl
+    - dupword
+    - durationcheck
     - errcheck
-    - gci
+    - errchkjson
+    - errname
+    - errorlint
+    - execinquery
+    - exhaustive
+    - exportloopref
+    - forcetypeassert
+    - gochecknoinits
     - gocognit
-    - nestif
+    - gocritic
-      # - gocritic # ref: https://github.com/golangci/golangci-lint/issues/2649#issue-1170906525
+    - gocyclo
+    - goerr113
+    - gofmt
     - gofumpt
     - goimports
+    - gosec
     - gosimple
+    - gosmopolitan
     - govet
+    - ineffassign
+    - makezero
+    - mirror
     - misspell
+    - nestif
+    - nolintlint
+    - prealloc
+    - predeclared
+    - revive
+    - sqlclosecheck
     - staticcheck
-    - stylecheck
+    - unconvert
     - unparam
     - unused
+    - usestdlibvars
+    - wastedassign
   fast: false
 
 

bot/access.go

@@ -32,7 +32,7 @@ func (b *Bot) allowUsers(actorID id.UserID) bool {
 	return true
 }
 
-func (b *Bot) allowAnyone(actorID id.UserID, targetRoomID id.RoomID) bool {
+func (b *Bot) allowAnyone(_ id.UserID, _ id.RoomID) bool {
 	return true
 }
 
@@ -54,7 +54,7 @@ func (b *Bot) allowOwner(actorID id.UserID, targetRoomID id.RoomID) bool {
 	return owner == actorID.String()
 }
 
-func (b *Bot) allowAdmin(actorID id.UserID, targetRoomID id.RoomID) bool {
+func (b *Bot) allowAdmin(actorID id.UserID, _ id.RoomID) bool {
 	return mxidwc.Match(actorID.String(), b.allowedAdmins)
 }
 

bot/bot.go

@@ -91,14 +91,14 @@ func New(
 }
 
 // Error message to the log and matrix room
-func (b *Bot) Error(ctx context.Context, message string, args ...interface{}) {
+func (b *Bot) Error(ctx context.Context, message string, args ...any) {
 	evt := eventFromContext(ctx)
 	threadID := threadIDFromContext(ctx)
 	if threadID == "" {
 		threadID = linkpearl.EventParent(evt.ID, evt.Content.AsMessage())
 	}
 
-	err := fmt.Errorf(message, args...)
+	err := fmt.Errorf(message, args...) //nolint:goerr113 // we have to
 	b.log.Error().Err(err).Msg(err.Error())
 	if evt == nil {
 		return

bot/command.go

@@ -2,6 +2,7 @@ package bot
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"strings"
 	"time"
@@ -372,7 +373,7 @@ func (b *Bot) handle(ctx context.Context) {
 	if err != nil {
 		b.log.Error().Err(err).Msg("cannot send typing notification")
 	}
-	defer b.lp.GetClient().UserTyping(evt.RoomID, false, 30*time.Second) //nolint:errcheck
+	defer b.lp.GetClient().UserTyping(evt.RoomID, false, 30*time.Second) //nolint:errcheck // we don't care
 
 	if !cmd.allowed(evt.Sender, evt.RoomID) {
 		b.lp.SendNotice(evt.RoomID, "not allowed to do that, kupo")
@@ -413,9 +414,9 @@ func (b *Bot) handle(ctx context.Context) {
 	case commandBanlistTotals:
 		b.runBanlistTotals(ctx)
 	case commandBanlistAdd:
-		b.runBanlistAdd(ctx, commandSlice)
+		b.runBanlistChange(ctx, "add", commandSlice)
 	case commandBanlistRemove:
-		b.runBanlistRemove(ctx, commandSlice)
+		b.runBanlistChange(ctx, "remove", commandSlice)
 	case commandBanlistReset:
 		b.runBanlistReset(ctx)
 	case commandMailboxes:
@@ -543,7 +544,7 @@ func (b *Bot) runSend(ctx context.Context) {
 	b.runSendCommand(ctx, cfg, tos, subject, body, htmlBody)
 }
 
-func (b *Bot) getSendDetails(ctx context.Context) (string, string, string, bool) {
+func (b *Bot) getSendDetails(ctx context.Context) (to, subject, body string, ok bool) {
 	evt := eventFromContext(ctx)
 	if !b.allowSend(evt.Sender, evt.RoomID) {
 		return "", "", "", false
@@ -556,8 +557,8 @@ func (b *Bot) getSendDetails(ctx context.Context) (string, string, string, bool)
 	}
 
 	commandSlice := b.parseCommand(evt.Content.AsMessage().Body, false)
-	to, subject, body, err := utils.ParseSend(commandSlice)
+	to, subject, body, err = utils.ParseSend(commandSlice)
-	if err == utils.ErrInvalidArgs {
+	if errors.Is(err, utils.ErrInvalidArgs) {
 		b.lp.SendNotice(evt.RoomID, fmt.Sprintf(
 			"Usage:\n"+
 				"```\n"+

bot/command_admin.go

@@ -21,7 +21,7 @@ func (b *Bot) sendMailboxes(ctx context.Context) {
 	evt := eventFromContext(ctx)
 	mailboxes := map[string]config.Room{}
 	slice := []string{}
-	b.rooms.Range(func(key any, value any) bool {
+	b.rooms.Range(func(key, value any) bool {
 		if key == nil {
 			return true
 		}
@@ -37,12 +37,12 @@ func (b *Bot) sendMailboxes(ctx context.Context) {
 		if !ok {
 			return true
 		}
-		config, err := b.cfg.GetRoom(roomID)
+		cfg, err := b.cfg.GetRoom(roomID)
 		if err != nil {
 			b.log.Error().Err(err).Msg("cannot retrieve settings")
 		}
 
-		mailboxes[mailbox] = config
+		mailboxes[mailbox] = cfg
 		slice = append(slice, mailbox)
 		return true
 	})
@@ -80,7 +80,10 @@ func (b *Bot) runDelete(ctx context.Context, commandSlice []string) {
 		b.lp.SendNotice(evt.RoomID, "mailbox does not exists, kupo", linkpearl.RelatesTo(evt.ID))
 		return
 	}
-	roomID := v.(id.RoomID)
+	roomID, ok := v.(id.RoomID)
+	if !ok {
+		return
+	}
 
 	b.rooms.Delete(mailbox)
 	err := b.cfg.SetRoom(roomID, config.Room{})
@@ -350,7 +353,7 @@ func (b *Bot) runBanlistTotals(ctx context.Context) {
 	b.addBanlistTimeline(ctx, true)
 }
 
-func (b *Bot) runBanlistAuth(ctx context.Context, commandSlice []string) {
+func (b *Bot) runBanlistAuth(ctx context.Context, commandSlice []string) { //nolint:dupl // not in that case
 	evt := eventFromContext(ctx)
 	cfg := b.cfg.GetBot()
 	if len(commandSlice) < 2 {
@@ -377,7 +380,7 @@ func (b *Bot) runBanlistAuth(ctx context.Context, commandSlice []string) {
 	b.lp.SendNotice(evt.RoomID, "auth banning has been updated", linkpearl.RelatesTo(evt.ID))
 }
 
-func (b *Bot) runBanlistAuto(ctx context.Context, commandSlice []string) {
+func (b *Bot) runBanlistAuto(ctx context.Context, commandSlice []string) { //nolint:dupl // not in that case
 	evt := eventFromContext(ctx)
 	cfg := b.cfg.GetBot()
 	if len(commandSlice) < 2 {
@@ -404,7 +407,7 @@ func (b *Bot) runBanlistAuto(ctx context.Context, commandSlice []string) {
 	b.lp.SendNotice(evt.RoomID, "auto banning has been updated", linkpearl.RelatesTo(evt.ID))
 }
 
-func (b *Bot) runBanlistAdd(ctx context.Context, commandSlice []string) {
+func (b *Bot) runBanlistChange(ctx context.Context, mode string, commandSlice []string) {
 	evt := eventFromContext(ctx)
 	if len(commandSlice) < 2 {
 		b.runBanlist(ctx, commandSlice)
@@ -416,37 +419,13 @@ func (b *Bot) runBanlistAdd(ctx context.Context, commandSlice []string) {
 	}
 	banlist := b.cfg.GetBanlist()
 
-	ips := commandSlice[1:]
+	var action func(net.Addr)
-	for _, ip := range ips {
+	if mode == "remove" {
-		addr, err := net.ResolveIPAddr("ip", ip)
+		action = banlist.Remove
-		if err != nil {
+	} else {
-			b.Error(ctx, "cannot add %s to banlist: %v", ip, err)
+		action = banlist.Add
-			return
-		}
-		banlist.Add(addr)
 	}
 
-	err := b.cfg.SetBanlist(banlist)
-	if err != nil {
-		b.Error(ctx, "cannot set banlist: %v", err)
-		return
-	}
-
-	b.lp.SendNotice(evt.RoomID, "banlist has been updated, kupo", linkpearl.RelatesTo(evt.ID))
-}
-
-func (b *Bot) runBanlistRemove(ctx context.Context, commandSlice []string) {
-	evt := eventFromContext(ctx)
-	if len(commandSlice) < 2 {
-		b.runBanlist(ctx, commandSlice)
-		return
-	}
-	if !b.cfg.GetBot().BanlistEnabled() {
-		b.lp.SendNotice(evt.RoomID, "banlist is disabled, you have to enable it first, kupo", linkpearl.RelatesTo(evt.ID))
-		return
-	}
-	banlist := b.cfg.GetBanlist()
-
 	ips := commandSlice[1:]
 	for _, ip := range ips {
 		addr, err := net.ResolveIPAddr("ip", ip)
@@ -454,7 +433,7 @@ func (b *Bot) runBanlistRemove(ctx context.Context, commandSlice []string) {
 			b.Error(ctx, "cannot remove %s from banlist: %v", ip, err)
 			return
 		}
-		banlist.Remove(addr)
+		action(addr)
 	}
 
 	err := b.cfg.SetBanlist(banlist)

bot/email.go

@@ -15,14 +15,12 @@ import (
 	"gitlab.com/etke.cc/postmoogle/utils"
 )
 
-// account data keys
 const (
+	// account data keys
 	acMessagePrefix   = "cc.etke.postmoogle.message"
 	acLastEventPrefix = "cc.etke.postmoogle.last"
-)
 
-// event keys
+	// event keys
-const (
 	eventMessageIDkey  = "cc.etke.postmoogle.messageID"
 	eventReferencesKey = "cc.etke.postmoogle.references"
 	eventInReplyToKey  = "cc.etke.postmoogle.inReplyTo"
@@ -33,6 +31,8 @@ const (
 	eventCcKey         = "cc.etke.postmoogle.cc"
 )
 
+var ErrNoRoom = errors.New("room not found")
+
 // SetSendmail sets mail sending func to the bot
 func (b *Bot) SetSendmail(sendmail func(string, string, string) error) {
 	b.sendmail = sendmail
@@ -40,8 +40,8 @@ func (b *Bot) SetSendmail(sendmail func(string, string, string) error) {
 }
 
 func (b *Bot) shouldQueue(msg string) bool {
-	errors := strings.Split(msg, ";")
+	errs := strings.Split(msg, ";")
-	for _, err := range errors {
+	for _, err := range errs {
 		errParts := strings.Split(strings.TrimSpace(err), ":")
 		if len(errParts) < 2 {
 			continue
@@ -114,10 +114,10 @@ func (b *Bot) GetIFOptions(roomID id.RoomID) email.IncomingFilteringOptions {
 // IncomingEmail sends incoming email to matrix room
 //
 //nolint:gocognit // TODO
-func (b *Bot) IncomingEmail(ctx context.Context, email *email.Email) error {
+func (b *Bot) IncomingEmail(ctx context.Context, eml *email.Email) error {
-	roomID, ok := b.GetMapping(email.Mailbox(true))
+	roomID, ok := b.GetMapping(eml.Mailbox(true))
 	if !ok {
-		return errors.New("room not found")
+		return ErrNoRoom
 	}
 	cfg, err := b.cfg.GetRoom(roomID)
 	if err != nil {
@@ -129,18 +129,18 @@ func (b *Bot) IncomingEmail(ctx context.Context, email *email.Email) error {
 
 	var threadID id.EventID
 	newThread := true
-	if email.InReplyTo != "" || email.References != "" {
+	if eml.InReplyTo != "" || eml.References != "" {
-		threadID = b.getThreadID(roomID, email.InReplyTo, email.References)
+		threadID = b.getThreadID(roomID, eml.InReplyTo, eml.References)
 		if threadID != "" {
 			newThread = false
 			ctx = threadIDToContext(ctx, threadID)
-			b.setThreadID(roomID, email.MessageID, threadID)
+			b.setThreadID(roomID, eml.MessageID, threadID)
 		}
 	}
-	content := email.Content(threadID, cfg.ContentOptions())
+	content := eml.Content(threadID, cfg.ContentOptions())
 	eventID, serr := b.lp.Send(roomID, content)
 	if serr != nil {
-		if !strings.Contains(serr.Error(), "M_UNKNOWN") { // 	if it's not an unknown event event error
+		if !strings.Contains(serr.Error(), "M_UNKNOWN") { // if it's not an unknown event error
 			return serr
 		}
 		threadID = "" // unknown event edge case - remove existing thread ID to avoid complications
@@ -151,15 +151,15 @@ func (b *Bot) IncomingEmail(ctx context.Context, email *email.Email) error {
 		ctx = threadIDToContext(ctx, threadID)
 	}
 
-	b.setThreadID(roomID, email.MessageID, threadID)
+	b.setThreadID(roomID, eml.MessageID, threadID)
 	b.setLastEventID(roomID, threadID, eventID)
 
 	if !cfg.NoInlines() {
-		b.sendFiles(ctx, roomID, email.InlineFiles, cfg.NoThreads(), threadID)
+		b.sendFiles(ctx, roomID, eml.InlineFiles, cfg.NoThreads(), threadID)
 	}
 
 	if !cfg.NoFiles() {
-		b.sendFiles(ctx, roomID, email.Files, cfg.NoThreads(), threadID)
+		b.sendFiles(ctx, roomID, eml.Files, cfg.NoThreads(), threadID)
 	}
 
 	if newThread && cfg.Autoreply() != "" {
@@ -255,8 +255,9 @@ func (b *Bot) sendAutoreply(roomID id.RoomID, threadID id.EventID) {
 	b.saveSentMetadata(ctx, queued, meta.ThreadID, recipients, eml, cfg, "Autoreply has been sent")
 }
 
-func (b *Bot) canReply(sender id.UserID, roomID id.RoomID) bool {
+func (b *Bot) canReply(ctx context.Context) bool {
-	return b.allowSend(sender, roomID) && b.allowReply(sender, roomID)
+	evt := eventFromContext(ctx)
+	return b.allowSend(evt.Sender, evt.RoomID) && b.allowReply(evt.Sender, evt.RoomID)
 }
 
 // SendEmailReply sends replies from matrix thread to email thread
@@ -264,7 +265,7 @@ func (b *Bot) canReply(sender id.UserID, roomID id.RoomID) bool {
 //nolint:gocognit // TODO
 func (b *Bot) SendEmailReply(ctx context.Context) {
 	evt := eventFromContext(ctx)
-	if !b.canReply(evt.Sender, evt.RoomID) {
+	if !b.canReply(ctx) {
 		return
 	}
 	cfg, err := b.cfg.GetRoom(evt.RoomID)
@@ -543,7 +544,7 @@ func (b *Bot) sendFiles(ctx context.Context, roomID id.RoomID, files []*utils.Fi
 	}
 }
 
-func (b *Bot) getThreadID(roomID id.RoomID, messageID string, references string) id.EventID {
+func (b *Bot) getThreadID(roomID id.RoomID, messageID, references string) id.EventID {
 	refs := []string{messageID}
 	if references != "" {
 		refs = append(refs, strings.Split(references, " ")...)
@@ -592,7 +593,7 @@ func (b *Bot) getLastEventID(roomID id.RoomID, threadID id.EventID) id.EventID {
 	return threadID
 }
 
-func (b *Bot) setLastEventID(roomID id.RoomID, threadID id.EventID, eventID id.EventID) {
+func (b *Bot) setLastEventID(roomID id.RoomID, threadID, eventID id.EventID) {
 	key := acLastEventPrefix + "." + threadID.String()
 	err := b.lp.SetRoomAccountData(roomID, key, map[string]string{"eventID": eventID.String()})
 	if err != nil {

bot/reaction.go

@@ -38,8 +38,7 @@ func (b *Bot) handleReaction(ctx context.Context) {
 	ctx = threadIDToContext(ctx, threadID)
 	linkpearl.ParseContent(evt, b.log)
 
-	switch action {
+	if action == commandSpamlistAdd {
-	case commandSpamlistAdd:
 		sender := linkpearl.EventField[string](&srcEvt.Content, eventFromKey)
 		if sender == "" {
 			b.Error(ctx, "cannot get sender of the email")

cmd/cmd.go

@@ -111,7 +111,6 @@ func initMatrix(cfg *config.Config) {
 		Logger:            log,
 	})
 	if err != nil {
-		// nolint // Fatal = panic, not os.Exit()
 		log.Fatal().Err(err).Msg("cannot initialize matrix bot")
 	}
 

email/email.go

@@ -159,7 +159,7 @@ func (e *Email) Content(threadID id.EventID, options *ContentOptions) *event.Con
 	}
 
 	content := event.Content{
-		Raw: map[string]interface{}{
+		Raw: map[string]any{
 			options.MessageIDKey:  e.MessageID,
 			options.InReplyToKey:  e.InReplyTo,
 			options.ReferencesKey: e.References,
@@ -231,7 +231,10 @@ func (e *Email) sign(domain, privkey string, data strings.Builder) string {
 	if err != nil {
 		return data.String()
 	}
-	signer := parsedkey.(crypto.Signer)
+	signer, ok := parsedkey.(crypto.Signer)
+	if !ok {
+		return data.String()
+	}
 
 	options := &dkim.SignOptions{
 		Domain:   domain,

email/utils.go

@@ -10,7 +10,7 @@ import (
 	"maunium.net/go/mautrix/id"
 )
 
-var styleRegex = regexp.MustCompile("<style((.|\n|\r)*?)<\\/style>")
+var styleRegex = regexp.MustCompile("<style((.|\n|\r)*?)</style>")
 
 // AddressValid checks if email address is valid
 func AddressValid(email string) bool {

justfile

@@ -4,12 +4,6 @@ project := file_name(repo)
 gitlab_image := "registry." + repo + ":" + tag
 etke_image := replace(gitlab_image, "gitlab.com", "etke.cc")
 
-try:
-    @echo {{ project }}
-    @echo {{ repo }}
-    @echo {{ gitlab_image }}
-    @echo {{ etke_image }}
-
 # show help by default
 default:
     @just --list --justfile {{ justfile() }}
@@ -22,7 +16,7 @@ update:
     go mod vendor
 
 # run linter
-lint: try
+lint:
     golangci-lint run ./...
 
 # automatically fix liter issues
@@ -30,7 +24,7 @@ lintfix:
     golangci-lint run --fix ./...
 
 # run unit tests
-test: try
+test:
     @go test -cover -coverprofile=cover.out -coverpkg=./... -covermode=set ./...
     @go tool cover -func=cover.out
     -@rm -f cover.out
@@ -44,10 +38,10 @@ build:
     go build -v -o {{ project }} ./cmd
 
 # docker login
-login: try
+login:
     @docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
 
 # docker build
-docker: try
+docker:
     docker buildx create --use
     docker buildx build --pull --platform linux/arm64/v8,linux/amd64 --push -t {{ gitlab_image }} -t {{ etke_image }} .

smtp/client.go

@@ -11,7 +11,7 @@ import (
 )
 
 type MailSender interface {
-	Send(from string, to string, data string) error
+	Send(from, to, data string) error
 }
 
 // SMTP client
@@ -28,7 +28,7 @@ func newClient(cfg *RelayConfig, log *zerolog.Logger) *Client {
 }
 
 // Send email
-func (c Client) Send(from string, to string, data string) error {
+func (c Client) Send(from, to, data string) error {
 	c.log.Debug().Str("from", from).Str("to", to).Msg("sending email")
 
 	var conn *smtp.Client
@@ -67,7 +67,7 @@ func (c Client) Send(from string, to string, data string) error {
 }
 
 // createDirectClient connects directly to the provided smtp host
-func (c *Client) createDirectClient(from string, to string) (*smtp.Client, error) {
+func (c *Client) createDirectClient(from, to string) (*smtp.Client, error) {
 	localname := strings.SplitN(from, "@", 2)[1]
 	target := c.config.Host + ":" + c.config.Port
 	conn, err := smtp.Dial(target)
@@ -81,8 +81,8 @@ func (c *Client) createDirectClient(from string, to string) (*smtp.Client, error
 	}
 
 	if ok, _ := conn.Extension("STARTTLS"); ok {
-		config := &tls.Config{ServerName: c.config.Host}
+		config := &tls.Config{ServerName: c.config.Host} //nolint:gosec // it's smtp, even that is too strict sometimes
-		conn.StartTLS(config) //nolint:errcheck // if it doesn't work - we can't do anything anyway
+		conn.StartTLS(config)                            //nolint:errcheck // if it doesn't work - we can't do anything anyway
 	}
 
 	if c.config.Usename != "" {

smtp/logger.go

@@ -11,24 +11,24 @@ type validatorLoggerWrapper struct {
 	log *zerolog.Logger
 }
 
-func (l validatorLoggerWrapper) Info(msg string, args ...interface{}) {
+func (l validatorLoggerWrapper) Info(msg string, args ...any) {
 	l.log.Info().Msgf(msg, args...)
 }
 
-func (l validatorLoggerWrapper) Error(msg string, args ...interface{}) {
+func (l validatorLoggerWrapper) Error(msg string, args ...any) {
 	l.log.Error().Msgf(msg, args...)
 }
 
 // loggerWrapper is a wrapper around any logger to implement smtp.Logger interface
 type loggerWrapper struct {
-	log func(string, ...interface{})
+	log func(string, ...any)
 }
 
-func (l loggerWrapper) Printf(format string, v ...interface{}) {
+func (l loggerWrapper) Printf(format string, v ...any) {
 	l.log(format, v...)
 }
 
-func (l loggerWrapper) Println(v ...interface{}) {
+func (l loggerWrapper) Println(v ...any) {
 	msg := strings.Repeat("%v ", len(v))
 	l.log(msg, v...)
 }

smtp/manager.go

@@ -90,7 +90,7 @@ func NewManager(cfg *Config) *Manager {
 	}
 
 	s := smtp.NewServer(mailsrv)
-	s.ErrorLog = loggerWrapper{func(s string, i ...interface{}) { cfg.Logger.Error().Msgf(s, i...) }}
+	s.ErrorLog = loggerWrapper{func(s string, i ...any) { cfg.Logger.Error().Msgf(s, i...) }}
 	s.ReadTimeout = 10 * time.Second
 	s.WriteTimeout = 10 * time.Second
 	s.MaxMessageBytes = cfg.MaxSize * 1024 * 1024
@@ -209,7 +209,7 @@ func (m *Manager) loadTLSConfig() bool {
 		return false
 	}
 
-	m.tls.Config = &tls.Config{Certificates: certificates}
+	m.tls.Config = &tls.Config{Certificates: certificates} //nolint:gosec // it's email, even that config is too strict sometimes
 	m.smtp.TLSConfig = m.tls.Config
 	return true
 }

smtp/server.go

@@ -10,17 +10,28 @@ import (
 	"gitlab.com/etke.cc/postmoogle/email"
 )
 
+const (
+	// NoUserCode SMTP code
+	NoUserCode = 550
+	// BannedCode SMTP code
+	BannedCode = 554
+)
+
 var (
+	// NoUserEnhancedCode enhanced SMTP code
+	NoUserEnhancedCode = smtp.EnhancedCode{5, 5, 0}
+	// BannedEnhancedCode enhanced SMTP code
+	BannedEnhancedCode = smtp.EnhancedCode{5, 5, 4}
 	// ErrBanned returned to banned hosts
 	ErrBanned = &smtp.SMTPError{
-		Code:         554,
+		Code:         BannedCode,
-		EnhancedCode: smtp.EnhancedCode{5, 5, 4},
+		EnhancedCode: BannedEnhancedCode,
 		Message:      "please, don't bother me anymore, kupo.",
 	}
 	// ErrNoUser returned when no such mailbox found
 	ErrNoUser = &smtp.SMTPError{
-		Code:         550,
+		Code:         NoUserCode,
-		EnhancedCode: smtp.EnhancedCode{5, 5, 0},
+		EnhancedCode: NoUserEnhancedCode,
 		Message:      "no such user here, kupo.",
 	}
 )

smtp/session.go

@@ -20,6 +20,16 @@ import (
 	"gitlab.com/etke.cc/postmoogle/utils"
 )
 
+// GraylistCode SMTP code
+const GraylistCode = 451
+
+var (
+	// ErrInvalidEmail for invalid emails :)
+	ErrInvalidEmail = errors.New("please, provide valid email address")
+	// GraylistEnhancedCode is GraylistCode in enhanced code notation
+	GraylistEnhancedCode = smtp.EnhancedCode{4, 5, 1}
+)
+
 // incomingSession represents an SMTP-submission session receiving emails from remote servers
 type incomingSession struct {
 	log          *zerolog.Logger
@@ -32,7 +42,7 @@ type incomingSession struct {
 	domains      []string
 	roomID       id.RoomID
 
-	ctx  context.Context
+	ctx  context.Context //nolint:containedctx // that's session
 	addr net.Addr
 	tos  []string
 	from string
@@ -89,13 +99,13 @@ func (s *incomingSession) getAddr(envelope *enmime.Envelope) net.Addr {
 		return s.addr
 	}
 
-	host, portString, _ := net.SplitHostPort(addrHeader) //nolint:errcheck
+	host, portString, _ := net.SplitHostPort(addrHeader) //nolint:errcheck // it is real addr
 	if host == "" {
 		return s.addr
 	}
 
 	var port int
-	port, _ = strconv.Atoi(portString) //nolint:errcheck
+	port, _ = strconv.Atoi(portString) //nolint:errcheck // it's a real addr
 
 	realAddr := &net.TCPAddr{IP: net.ParseIP(host), Port: port}
 	s.log.Info().Str("addr", realAddr.String()).Msg("real address")
@@ -115,7 +125,7 @@ func (s *incomingSession) Data(r io.Reader) error {
 		return err
 	}
 	addr := s.getAddr(envelope)
-	reader.Seek(0, io.SeekStart) //nolint:errcheck
+	reader.Seek(0, io.SeekStart) //nolint:errcheck // becase we're sure that's ok
 	validations := s.getFilters(s.roomID)
 	if !validateIncoming(s.from, s.tos[0], addr, s.log, validations) {
 		s.ban(addr)
@@ -123,8 +133,8 @@ func (s *incomingSession) Data(r io.Reader) error {
 	}
 	if s.greylisted(addr) {
 		return &smtp.SMTPError{
-			Code:         451,
+			Code:         GraylistCode,
-			EnhancedCode: smtp.EnhancedCode{4, 5, 1},
+			EnhancedCode: GraylistEnhancedCode,
 			Message:      "You have been greylisted, try again a bit later.",
 		}
 	}
@@ -164,16 +174,16 @@ type outgoingSession struct {
 	domains   []string
 	getRoomID func(string) (id.RoomID, bool)
 
-	ctx      context.Context
+	ctx      context.Context //nolint:containedctx // that's session
 	tos      []string
 	from     string
 	fromRoom id.RoomID
 }
 
-func (s *outgoingSession) Mail(from string, opts smtp.MailOptions) error {
+func (s *outgoingSession) Mail(from string, _ smtp.MailOptions) error {
 	sentry.GetHubFromContext(s.ctx).Scope().SetTag("from", from)
 	if !email.AddressValid(from) {
-		return errors.New("please, provide email address")
+		return ErrInvalidEmail
 	}
 	hostname := utils.Hostname(from)
 	var domainok bool
@@ -234,7 +244,7 @@ func validateIncoming(from, to string, senderAddr net.Addr, log *zerolog.Logger,
 	case *net.TCPAddr:
 		sender = netaddr.IP
 	default:
-		host, _, _ := net.SplitHostPort(senderAddr.String()) // nolint:errcheck
+		host, _, _ := net.SplitHostPort(senderAddr.String()) //nolint:errcheck // interface constraints
 		sender = net.ParseIP(host)
 	}
 

utils/command.go

@@ -5,21 +5,24 @@ import (
 	"strings"
 )
 
+// MinSendCommandParts is minimal count of space-separated parts for !pm send command
+const MinSendCommandParts = 3
+
 // ErrInvalidArgs returned when a command's arguments are invalid
 var ErrInvalidArgs = fmt.Errorf("invalid arguments")
 
 // ParseSend parses "!pm send" command, returns to, subject, body, err
-func ParseSend(commandSlice []string) (string, string, string, error) {
+func ParseSend(commandSlice []string) (to, subject, body string, err error) {
 	message := strings.Join(commandSlice, " ")
 	lines := strings.Split(message, "\n")
-	if len(lines) < 3 {
+	if len(lines) < MinSendCommandParts {
 		return "", "", "", ErrInvalidArgs
 	}
 
 	commandSlice = strings.Split(lines[0], " ")
-	to := commandSlice[1]
+	to = commandSlice[1]
-	subject := lines[1]
+	subject = lines[1]
-	body := strings.Join(lines[2:], "\n")
+	body = strings.Join(lines[2:], "\n")
 
 	return to, subject, body, nil
 }

utils/mail.go

@@ -25,8 +25,7 @@ func Hostname(email string) string {
 }
 
 // EmailParts parses email address into mailbox, subaddress, and hostname
-func EmailParts(email string) (string, string, string) {
+func EmailParts(email string) (mailbox, sub, hostname string) {
-	var mailbox, hostname string
 	address, err := emailaddress.Parse(email)
 	if err == nil {
 		mailbox = address.LocalPart
@@ -44,7 +43,6 @@ func EmailParts(email string) (string, string, string) {
 		}
 	}
 
-	var sub string
 	idx := strings.Index(mailbox, "+")
 	if idx != -1 {
 		sub = strings.ReplaceAll(mailbox[idx:], "+", "")
@@ -54,7 +52,7 @@ func EmailParts(email string) (string, string, string) {
 }
 
 // EmailsList returns human-readable list of mailbox's emails for all available domains
-func EmailsList(mailbox string, domain string) string {
+func EmailsList(mailbox, domain string) string {
 	var msg strings.Builder
 	domain = SanitizeDomain(domain)
 	msg.WriteString(mailbox)