in store/, change functions from calling panic to returning errors

this is a library package, errors should be explicit. callers had to be careful
when calling these "X" functions. now it's explicit.

http/import.go

@@ -467,11 +467,6 @@ func importMessages(ctx context.Context, log *mlog.Log, token string, acc *store
 				err = f.Close()
 				log.Check(err, "closing temporary message file for delivery")
 			}
-			x := recover()
-			if x != nil {
-				// todo: get a variant of DeliverX that returns an error instead of panicking.
-				log.Error("delivery panic", mlog.Field("err", x))
-			}
 		}()
 		m.MailboxID = mb.ID
 		m.MailboxOrigID = mb.ID
@@ -503,7 +498,10 @@ func importMessages(ctx context.Context, log *mlog.Log, token string, acc *store
 		const consumeFile = true
 		const sync = false
 		const notrain = true
-		acc.DeliverX(log, tx, m, f, consumeFile, mb.Sent, sync, notrain) // todo: need a deliver that returns an error.
+		if err := acc.DeliverMessage(log, tx, m, f, consumeFile, mb.Sent, sync, notrain); err != nil {
+			problemf("delivering message %s: %s (continuing)", pos, err)
+			return
+		}
 		deliveredIDs = append(deliveredIDs, m.ID)
 		changes = append(changes, store.ChangeAddUID{MailboxID: m.MailboxID, UID: m.UID, Flags: m.Flags})
 		messages[mb.Name]++

imapserver/server.go

@@ -654,10 +654,10 @@ func serve(listenerName string, cid int64, tlsConfig *tls.Config, nc net.Conn, x
 		x := recover()
 		if x == nil || x == cleanClose {
 			c.log.Info("connection closed")
-		} else if err, ok := x.(error); ok || isClosed(err) {
+		} else if err, ok := x.(error); ok && isClosed(err) {
 			c.log.Infox("connection closed", err)
 		} else {
-			c.log.Error("unhandled error", mlog.Field("err", x))
+			c.log.Error("unhandled panic", mlog.Field("err", x))
 			debug.PrintStack()
 			metrics.PanicInc("imapserver")
 		}
@@ -739,6 +739,9 @@ func (c *conn) command() {
 			panic(x)
 		}
 
+		var sxerr syntaxError
+		var uerr userError
+		var serr serverError
 		if isClosed(err) {
 			c.log.Infox("imap command ioerror", err, logFields...)
 			result = "ioerror"
@@ -746,12 +749,7 @@ func (c *conn) command() {
 				debug.PrintStack()
 			}
 			panic(err)
-		}
+		} else if errors.As(err, &sxerr) {
-
-		var sxerr syntaxError
-		var uerr userError
-		var serr serverError
-		if errors.As(err, &sxerr) {
 			result = "badsyntax"
 			if c.ncmds == 0 {
 				// Other side is likely speaking something else than IMAP, send error message and
@@ -793,11 +791,10 @@ func (c *conn) command() {
 				c.bwriteresultf("%s NO %s %v", tag, cmd, err)
 			}
 		} else {
-			result = "error"
+			// Other type of panic, we pass it on, aborting the connection.
-			c.log.Infox("imap command error", err, logFields...)
+			result = "panic"
-			// todo: introduce a store.Error, and check for that, don't blindly pass on errors?
+			c.log.Errorx("imap command panic", err, logFields...)
-			debug.PrintStack()
+			panic(err)
-			c.bwriteresultf("%s NO %s %v", tag, cmd, err)
 		}
 	}()
 
@@ -1148,7 +1145,8 @@ func xcheckmailboxname(name string, allowInbox bool) string {
 // If the mailbox does not exist, panic is called with a user error.
 // Must be called with account rlock held.
 func (c *conn) xmailbox(tx *bstore.Tx, name string, missingErrCode string) store.Mailbox {
-	mb := c.account.MailboxFindX(tx, name)
+	mb, err := c.account.MailboxFind(tx, name)
+	xcheckf(err, "finding mailbox")
 	if mb == nil {
 		// missingErrCode can be empty, or e.g. TRYCREATE or ALREADYEXISTS.
 		xusercodeErrorf(missingErrCode, "%w", store.ErrUnknownMailbox)
@@ -1909,14 +1907,17 @@ func (c *conn) cmdCreate(tag, cmd string, p *parser) {
 					p += "/"
 				}
 				p += elem
-				if c.account.MailboxExistsX(tx, p) {
+				exists, err := c.account.MailboxExists(tx, p)
+				xcheckf(err, "checking if mailbox exists")
+				if exists {
 					if i == len(elems)-1 {
 						// ../rfc/9051:1914
 						xuserErrorf("mailbox already exists")
 					}
 					continue
 				}
-				_, nchanges := c.account.MailboxEnsureX(tx, p, true)
+				_, nchanges, err := c.account.MailboxEnsure(tx, p, true)
+				xcheckf(err, "ensuring mailbox exists")
 				changes = append(changes, nchanges...)
 				created = append(created, p)
 			}
@@ -2050,10 +2051,13 @@ func (c *conn) cmdRename(tag, cmd string, p *parser) {
 			// We do indeed create a new destination mailbox and actually move the messages.
 			// ../rfc/9051:2101
 			if src == "Inbox" {
-				if c.account.MailboxExistsX(tx, dst) {
+				exists, err := c.account.MailboxExists(tx, dst)
+				xcheckf(err, "checking if destination mailbox exists")
+				if exists {
 					xusercodeErrorf("ALREADYEXISTS", "destination mailbox %q already exists", dst)
 				}
-				srcMB := c.account.MailboxFindX(tx, src)
+				srcMB, err := c.account.MailboxFind(tx, src)
+				xcheckf(err, "finding source mailbox")
 				if srcMB == nil {
 					xserverErrorf("inbox not found")
 				}
@@ -2066,7 +2070,7 @@ func (c *conn) cmdRename(tag, cmd string, p *parser) {
 					UIDValidity: uidval,
 					UIDNext:     1,
 				}
-				err := tx.Insert(&dstMB)
+				err = tx.Insert(&dstMB)
 				xcheckf(err, "create new destination mailbox")
 
 				var messages []store.Message
@@ -2207,7 +2211,9 @@ func (c *conn) cmdSubscribe(tag, cmd string, p *parser) {
 		var changes []store.Change
 
 		c.xdbwrite(func(tx *bstore.Tx) {
-			changes = c.account.SubscriptionEnsureX(tx, name)
+			var err error
+			changes, err = c.account.SubscriptionEnsure(tx, name)
+			xcheckf(err, "ensuring subscription")
 		})
 
 		c.broadcast(changes)
@@ -2235,7 +2241,9 @@ func (c *conn) cmdUnsubscribe(tag, cmd string, p *parser) {
 			// It's OK if not currently subscribed, ../rfc/9051:2215
 			err := tx.Delete(&store.Subscription{Name: name})
 			if err == bstore.ErrAbsent {
-				if !c.account.MailboxExistsX(tx, name) {
+				exists, err := c.account.MailboxExists(tx, name)
+				xcheckf(err, "checking if mailbox exists")
+				if !exists {
 					xuserErrorf("mailbox does not exist")
 				}
 				return
@@ -2561,7 +2569,8 @@ func (c *conn) cmdAppend(tag, cmd string, p *parser) {
 				MsgPrefix:     msgPrefix,
 			}
 			isSent := name == "Sent"
-			c.account.DeliverX(c.log, tx, &msg, msgFile, true, isSent, true, false)
+			err := c.account.DeliverMessage(c.log, tx, &msg, msgFile, true, isSent, true, false)
+			xcheckf(err, "delivering message")
 		})
 
 		// Fetch pending changes, possibly with new UIDs, so we can apply them before adding our own new UID.

import.go

@@ -192,7 +192,6 @@ func importctl(ctl *ctl, mbox bool) {
 	// We will be delivering messages. If we fail halfway, we need to remove the created msg files.
 	var deliveredIDs []int64
 
-	// Handle errors from store.*X calls.
 	defer func() {
 		x := recover()
 		if x == nil {
@@ -225,7 +224,8 @@ func importctl(ctl *ctl, mbox bool) {
 		isSent := mailbox == "Sent"
 		const sync = false
 		const notrain = true
-		a.DeliverX(ctl.log, tx, m, mf, consumeFile, isSent, sync, notrain)
+		err := a.DeliverMessage(ctl.log, tx, m, mf, consumeFile, isSent, sync, notrain)
+		ctl.xcheck(err, "delivering message")
 		deliveredIDs = append(deliveredIDs, m.ID)
 		ctl.log.Debug("delivered message", mlog.Field("id", m.ID))
 		changes = append(changes, store.ChangeAddUID{MailboxID: m.MailboxID, UID: m.UID, Flags: m.Flags})
@@ -236,7 +236,8 @@ func importctl(ctl *ctl, mbox bool) {
 	a.WithWLock(func() {
 		// Ensure mailbox exists.
 		var mb store.Mailbox
-		mb, changes = a.MailboxEnsureX(tx, mailbox, true)
+		mb, changes, err = a.MailboxEnsure(tx, mailbox, true)
+		ctl.xcheck(err, "ensuring mailbox exists")
 
 		jf, _, err := a.OpenJunkFilter(ctl.log)
 		if err != nil && !errors.Is(err, store.ErrNoJunkFilter) {

smtpserver/analyze.go

@@ -2,6 +2,7 @@ package smtpserver
 
 import (
 	"context"
+	"fmt"
 	"net"
 	"os"
 	"time"
@@ -172,7 +173,10 @@ func analyze(ctx context.Context, log *mlog.Log, resolver dns.Resolver, d delive
 			if rs != nil {
 				mailbox = rs.Mailbox
 			}
-			mb := d.acc.MailboxFindX(tx, mailbox)
+			mb, err := d.acc.MailboxFind(tx, mailbox)
+			if err != nil {
+				return fmt.Errorf("finding destination mailbox: %w", err)
+			}
 			if mb != nil {
 				// We want to deliver to mb.ID, but this message may be rejected and sent to the
 				// Rejects mailbox instead, which MailboxID overwritten. Record the ID in
@@ -187,7 +191,6 @@ func analyze(ctx context.Context, log *mlog.Log, resolver dns.Resolver, d delive
 				log.Debug("mailbox not found in database", mlog.Field("mailbox", mailbox))
 			}
 
-			var err error
 			isjunk, conclusive, method, err = reputation(tx, log, d.m)
 			reason = string(method)
 			return err

smtpserver/server.go

@@ -577,7 +577,7 @@ func serve(listenerName string, cid int64, hostname dns.Domain, tlsConfig *tls.C
 		} else if err, ok := x.(error); ok && isClosed(err) {
 			c.log.Infox("connection closed", err)
 		} else {
-			c.log.Error("unhandled error", mlog.Field("err", x))
+			c.log.Error("unhandled panic", mlog.Field("err", x))
 			debug.PrintStack()
 			metrics.PanicInc("smtpserver")
 		}
@@ -679,7 +679,7 @@ func command(c *conn) {
 		} else {
 			// Other type of panic, we pass it on, aborting the connection.
 			c.log.Errorx("command panic", err)
-			panic(x)
+			panic(err)
 		}
 	}()
 

store/account.go

@@ -20,7 +20,6 @@ database.
 package store
 
 // todo: make up a function naming scheme that indicates whether caller should broadcast changes.
-// todo: fewer (no?) "X" functions, but only explicit error handling.
 
 import (
 	"context"
@@ -394,13 +393,6 @@ type Account struct {
 	nused int // Reference count, while >0, this account is alive and shared.
 }
 
-func xcheckf(err error, format string, args ...any) {
-	if err != nil {
-		msg := fmt.Sprintf(format, args...)
-		panic(fmt.Errorf("%s: %w", msg, err))
-	}
-}
-
 // InitialUIDValidity returns a UIDValidity used for initializing an account.
 // It can be replaced during tests with a predictable value.
 var InitialUIDValidity = func() uint32 {
@@ -576,7 +568,7 @@ func (a *Account) WithRLock(fn func()) {
 	fn()
 }
 
-// DeliverX delivers a mail message to the account.
+// DeliverMessage delivers a mail message to the account.
 //
 // If consumeFile is set, the original msgFile is moved/renamed or copied and
 // removed as part of delivery.
@@ -594,14 +586,16 @@ func (a *Account) WithRLock(fn func()) {
 // Must be called with account rlock or wlock.
 //
 // Caller must broadcast new message.
-func (a *Account) DeliverX(log *mlog.Log, tx *bstore.Tx, m *Message, msgFile *os.File, consumeFile, isSent, sync, notrain bool) {
+func (a *Account) DeliverMessage(log *mlog.Log, tx *bstore.Tx, m *Message, msgFile *os.File, consumeFile, isSent, sync, notrain bool) error {
 	mb := Mailbox{ID: m.MailboxID}
-	err := tx.Get(&mb)
+	if err := tx.Get(&mb); err != nil {
-	xcheckf(err, "get mailbox")
+		return fmt.Errorf("get mailbox: %w", err)
+	}
 	m.UID = mb.UIDNext
 	mb.UIDNext++
-	err = tx.Update(&mb)
+	if err := tx.Update(&mb); err != nil {
-	xcheckf(err, "updating mailbox nextuid")
+		return fmt.Errorf("updating mailbox nextuid: %w", err)
+	}
 
 	conf, _ := a.Conf()
 	m.JunkFlagsForMailbox(mb.Name, conf)
@@ -616,7 +610,9 @@ func (a *Account) DeliverX(log *mlog.Log, tx *bstore.Tx, m *Message, msgFile *os
 		}
 		part = &p
 		buf, err := json.Marshal(part)
-		xcheckf(err, "marshal parsed message")
+		if err != nil {
+			return fmt.Errorf("marshal parsed message: %w", err)
+		}
 		m.ParsedBuf = buf
 	}
 
@@ -625,8 +621,9 @@ func (a *Account) DeliverX(log *mlog.Log, tx *bstore.Tx, m *Message, msgFile *os
 		m.MailboxDestinedID = 0
 	}
 
-	err = tx.Insert(m)
+	if err := tx.Insert(m); err != nil {
-	xcheckf(err, "inserting message")
+		return fmt.Errorf("inserting message: %w", err)
+	}
 
 	if isSent {
 		// Attempt to parse the message for its To/Cc/Bcc headers, which we insert into Recipient.
@@ -666,8 +663,9 @@ func (a *Account) DeliverX(log *mlog.Log, tx *bstore.Tx, m *Message, msgFile *os
 					OrgDomain: publicsuffix.Lookup(context.TODO(), d).Name(),
 					Sent:      sent,
 				}
-				err = tx.Insert(&mr)
+				if err := tx.Insert(&mr); err != nil {
-				xcheckf(err, "inserting sent message recipients")
+					return fmt.Errorf("inserting sent message recipients: %w", err)
+				}
 			}
 		}
 	}
@@ -678,30 +676,37 @@ func (a *Account) DeliverX(log *mlog.Log, tx *bstore.Tx, m *Message, msgFile *os
 
 	// Sync file data to disk.
 	if sync {
-		err = msgFile.Sync()
+		if err := msgFile.Sync(); err != nil {
-		xcheckf(err, "fsync message file")
+			return fmt.Errorf("fsync message file: %w", err)
+		}
 	}
 
 	if consumeFile {
-		err := os.Rename(msgFile.Name(), msgPath)
+		if err := os.Rename(msgFile.Name(), msgPath); err != nil {
-		xcheckf(err, "moving msg file to destination directory")
+			return fmt.Errorf("moving msg file to destination directory: %w", err)
+		}
 	} else if err := os.Link(msgFile.Name(), msgPath); err != nil {
 		// Assume file system does not support hardlinks. Copy it instead.
-		err := writeFile(msgPath, &moxio.AtReader{R: msgFile})
+		if err := writeFile(msgPath, &moxio.AtReader{R: msgFile}); err != nil {
-		xcheckf(err, "copying message to new file")
+			return fmt.Errorf("copying message to new file: %w", err)
+		}
 	}
 
 	if sync {
-		err = moxio.SyncDir(msgDir)
+		if err := moxio.SyncDir(msgDir); err != nil {
-		xcheckf(err, "sync directory")
+			return fmt.Errorf("sync directory: %w", err)
+		}
 	}
 
 	if !notrain && m.NeedsTraining() {
 		l := []Message{*m}
-		err = a.RetrainMessages(log, tx, l, false)
+		if err := a.RetrainMessages(log, tx, l, false); err != nil {
-		xcheckf(err, "training junkfilter")
+			return fmt.Errorf("training junkfilter: %w", err)
+		}
 		*m = l[0]
 	}
+
+	return nil
 }
 
 // write contents of r to new file dst, for delivering a message.
@@ -877,65 +882,50 @@ func (a *Account) MailboxEnsure(tx *bstore.Tx, name string, subscribe bool) (mb
 	return mb, changes, nil
 }
 
-// MailboxEnsureX calls MailboxEnsure, panicing with the error if it is not nil.
+// MailboxExists checks if mailbox exists.
-func (a *Account) MailboxEnsureX(tx *bstore.Tx, name string, subscribe bool) (Mailbox, []Change) {
-	mb, changes, err := a.MailboxEnsure(tx, name, subscribe)
-	if err != nil {
-		panic(err)
-	}
-	return mb, changes
-}
-
-// Check if mailbox exists.
 // Caller must hold account rlock.
-func (a *Account) MailboxExistsX(tx *bstore.Tx, name string) bool {
+func (a *Account) MailboxExists(tx *bstore.Tx, name string) (bool, error) {
 	q := bstore.QueryTx[Mailbox](tx)
 	q.FilterEqual("Name", name)
-	exists, err := q.Exists()
+	return q.Exists()
-	xcheckf(err, "checking existence")
-	return exists
 }
 
-// MailboxFindX finds a mailbox by name.
+// MailboxFind finds a mailbox by name, returning a nil mailbox and nil error if mailbox does not exist.
-func (a *Account) MailboxFindX(tx *bstore.Tx, name string) *Mailbox {
+func (a *Account) MailboxFind(tx *bstore.Tx, name string) (*Mailbox, error) {
 	q := bstore.QueryTx[Mailbox](tx)
 	q.FilterEqual("Name", name)
 	mb, err := q.Get()
 	if err == bstore.ErrAbsent {
-		return nil
+		return nil, nil
 	}
-	xcheckf(err, "lookup mailbox")
+	if err != nil {
-	return &mb
+		return nil, fmt.Errorf("looking up mailbox: %w", err)
+	}
+	return &mb, nil
 }
 
-// SubscriptionEnsureX ensures a subscription for name exists. The mailbox does not
+// SubscriptionEnsure ensures a subscription for name exists. The mailbox does not
 // have to exist. Any parents are not automatically subscribed.
-// Changes are broadcasted.
+// Changes are returned and must be broadcasted by the caller.
-func (a *Account) SubscriptionEnsureX(tx *bstore.Tx, name string) []Change {
+func (a *Account) SubscriptionEnsure(tx *bstore.Tx, name string) ([]Change, error) {
-	err := tx.Get(&Subscription{name})
+	if err := tx.Get(&Subscription{name}); err == nil {
-	if err == nil {
+		return nil, nil
-		return nil
 	}
 
-	err = tx.Insert(&Subscription{name})
+	if err := tx.Insert(&Subscription{name}); err != nil {
-	xcheckf(err, "inserting subscription")
+		return nil, fmt.Errorf("inserting subscription: %w", err)
+	}
 
 	q := bstore.QueryTx[Mailbox](tx)
 	q.FilterEqual("Name", name)
 	exists, err := q.Exists()
-	xcheckf(err, "looking up mailbox for subscription")
+	if err != nil {
+		return nil, fmt.Errorf("looking up mailbox for subscription: %w", err)
+	}
 	if exists {
-		return []Change{ChangeAddSubscription{name}}
+		return []Change{ChangeAddSubscription{name}}, nil
 	}
-	return []Change{ChangeAddMailbox{Name: name, Flags: []string{`\Subscribed`, `\NonExistent`}}}
+	return []Change{ChangeAddMailbox{Name: name, Flags: []string{`\Subscribed`, `\NonExistent`}}}, nil
-}
-
-// List mailboxes. Only those that exist, so names with only a subscription are not returned.
-// Caller must have account rlock held.
-func (a *Account) MailboxesX(tx *bstore.Tx) []Mailbox {
-	l, err := bstore.QueryTx[Mailbox](tx).List()
-	xcheckf(err, "fetching mailboxes")
-	return l
 }
 
 // MessageRuleset returns the first ruleset (if any) that message the message
@@ -1046,14 +1036,16 @@ func (a *Account) Deliver(log *mlog.Log, dest config.Destination, m *Message, ms
 // Message delivery and possible mailbox creation are broadcasted.
 func (a *Account) DeliverMailbox(log *mlog.Log, mailbox string, m *Message, msgFile *os.File, consumeFile bool) error {
 	var changes []Change
-	err := extransact(a.DB, true, func(tx *bstore.Tx) error {
+	err := a.DB.Write(func(tx *bstore.Tx) error {
-		mb, chl := a.MailboxEnsureX(tx, mailbox, true)
+		mb, chl, err := a.MailboxEnsure(tx, mailbox, true)
+		if err != nil {
+			return fmt.Errorf("ensuring mailbox: %w", err)
+		}
 		m.MailboxID = mb.ID
 		m.MailboxOrigID = mb.ID
 		changes = append(changes, chl...)
 
-		a.DeliverX(log, tx, m, msgFile, consumeFile, mb.Sent, true, false)
+		return a.DeliverMessage(log, tx, m, msgFile, consumeFile, mb.Sent, true, false)
-		return nil
 	})
 	// todo: if rename succeeded but transaction failed, we should remove the file.
 	if err != nil {
@@ -1083,8 +1075,11 @@ func (a *Account) TidyRejectsMailbox(log *mlog.Log, rejectsMailbox string) (hasS
 		}
 	}()
 
-	err := extransact(a.DB, true, func(tx *bstore.Tx) error {
+	err := a.DB.Write(func(tx *bstore.Tx) error {
-		mb := a.MailboxFindX(tx, rejectsMailbox)
+		mb, err := a.MailboxFind(tx, rejectsMailbox)
+		if err != nil {
+			return fmt.Errorf("finding mailbox: %w", err)
+		}
 		if mb == nil {
 			// No messages have been delivered yet.
 			hasSpace = true
@@ -1096,18 +1091,24 @@ func (a *Account) TidyRejectsMailbox(log *mlog.Log, rejectsMailbox string) (hasS
 		qdel := bstore.QueryTx[Message](tx)
 		qdel.FilterNonzero(Message{MailboxID: mb.ID})
 		qdel.FilterLess("Received", old)
-		var err error
 		remove, err = qdel.List()
-		xcheckf(err, "listing old messages")
+		if err != nil {
+			return fmt.Errorf("listing old messages: %w", err)
+		}
 
-		changes = a.xremoveMessages(log, tx, mb, remove)
+		changes, err = a.removeMessages(log, tx, mb, remove)
+		if err != nil {
+			return fmt.Errorf("removing messages: %w", err)
+		}
 
 		// We allow up to n messages.
 		qcount := bstore.QueryTx[Message](tx)
 		qcount.FilterNonzero(Message{MailboxID: mb.ID})
 		qcount.Limit(1000)
 		n, err := qcount.Count()
-		xcheckf(err, "counting rejects")
+		if err != nil {
+			return fmt.Errorf("counting rejects: %w", err)
+		}
 		hasSpace = n < 1000
 
 		return nil
@@ -1124,9 +1125,9 @@ func (a *Account) TidyRejectsMailbox(log *mlog.Log, rejectsMailbox string) (hasS
 	return hasSpace, nil
 }
 
-func (a *Account) xremoveMessages(log *mlog.Log, tx *bstore.Tx, mb *Mailbox, l []Message) []Change {
+func (a *Account) removeMessages(log *mlog.Log, tx *bstore.Tx, mb *Mailbox, l []Message) ([]Change, error) {
 	if len(l) == 0 {
-		return nil
+		return nil, nil
 	}
 	ids := make([]int64, len(l))
 	anyids := make([]any, len(l))
@@ -1139,30 +1140,33 @@ func (a *Account) xremoveMessages(log *mlog.Log, tx *bstore.Tx, mb *Mailbox, l [
 	// from a Sent mailbox to the rejects mailbox...
 	qdmr := bstore.QueryTx[Recipient](tx)
 	qdmr.FilterEqual("MessageID", anyids...)
-	_, err := qdmr.Delete()
+	if _, err := qdmr.Delete(); err != nil {
-	xcheckf(err, "deleting from message recipient")
+		return nil, fmt.Errorf("deleting from message recipient: %w", err)
+	}
 
 	// Actually remove the messages.
 	qdm := bstore.QueryTx[Message](tx)
 	qdm.FilterIDs(ids)
 	var deleted []Message
 	qdm.Gather(&deleted)
-	_, err = qdm.Delete()
+	if _, err := qdm.Delete(); err != nil {
-	xcheckf(err, "deleting from messages")
+		return nil, fmt.Errorf("deleting from messages: %w", err)
+	}
 
 	// Mark as neutral and train so junk filter gets untrained with these (junk) messages.
 	for i := range deleted {
 		deleted[i].Junk = false
 		deleted[i].Notjunk = false
 	}
-	err = a.RetrainMessages(log, tx, deleted, true)
+	if err := a.RetrainMessages(log, tx, deleted, true); err != nil {
-	xcheckf(err, "training deleted messages")
+		return nil, fmt.Errorf("training deleted messages: %w", err)
+	}
 
 	changes := make([]Change, len(l))
 	for i, m := range l {
 		changes[i] = ChangeRemoveUIDs{mb.ID, []UID{m.UID}}
 	}
-	return changes
+	return changes, nil
 }
 
 // RejectsRemove removes a message from the rejects mailbox if present.
@@ -1180,19 +1184,26 @@ func (a *Account) RejectsRemove(log *mlog.Log, rejectsMailbox, messageID string)
 		}
 	}()
 
-	err := extransact(a.DB, true, func(tx *bstore.Tx) error {
+	err := a.DB.Write(func(tx *bstore.Tx) error {
-		mb := a.MailboxFindX(tx, rejectsMailbox)
+		mb, err := a.MailboxFind(tx, rejectsMailbox)
+		if err != nil {
+			return fmt.Errorf("finding mailbox: %w", err)
+		}
 		if mb == nil {
 			return nil
 		}
 
 		q := bstore.QueryTx[Message](tx)
 		q.FilterNonzero(Message{MailboxID: mb.ID, MessageID: messageID})
-		var err error
 		remove, err = q.List()
-		xcheckf(err, "listing messages to remove")
+		if err != nil {
+			return fmt.Errorf("listing messages to remove: %w", err)
+		}
 
-		changes = a.xremoveMessages(log, tx, mb, remove)
+		changes, err = a.removeMessages(log, tx, mb, remove)
+		if err != nil {
+			return fmt.Errorf("removing messages: %w", err)
+		}
 
 		return nil
 	})

store/account_test.go

@@ -72,13 +72,15 @@ func TestMailbox(t *testing.T) {
 			tcheck(t, err, "sent mailbox")
 			msent.MailboxID = mbsent.ID
 			msent.MailboxOrigID = mbsent.ID
-			acc.DeliverX(xlog, tx, &msent, msgFile, false, true, true, false)
+			err = acc.DeliverMessage(xlog, tx, &msent, msgFile, false, true, true, false)
+			tcheck(t, err, "deliver message")
 
 			err = tx.Insert(&mbrejects)
 			tcheck(t, err, "insert rejects mailbox")
 			mreject.MailboxID = mbrejects.ID
 			mreject.MailboxOrigID = mbrejects.ID
-			acc.DeliverX(xlog, tx, &mreject, msgFile, false, false, true, false)
+			err = acc.DeliverMessage(xlog, tx, &mreject, msgFile, false, false, true, false)
+			tcheck(t, err, "deliver message")
 
 			return nil
 		})
@@ -133,44 +135,50 @@ func TestMailbox(t *testing.T) {
 
 	acc.WithWLock(func() {
 		err := acc.DB.Write(func(tx *bstore.Tx) error {
-			acc.MailboxEnsureX(tx, "Testbox", true)
+			_, _, err := acc.MailboxEnsure(tx, "Testbox", true)
-			return nil
+			return err
 		})
 		tcheck(t, err, "ensure mailbox exists")
 		err = acc.DB.Read(func(tx *bstore.Tx) error {
-			acc.MailboxEnsureX(tx, "Testbox", true)
+			_, _, err := acc.MailboxEnsure(tx, "Testbox", true)
-			return nil
+			return err
 		})
 		tcheck(t, err, "ensure mailbox exists")
 
 		err = acc.DB.Write(func(tx *bstore.Tx) error {
-			acc.MailboxEnsureX(tx, "Testbox2", false)
+			_, _, err := acc.MailboxEnsure(tx, "Testbox2", false)
 			tcheck(t, err, "create mailbox")
 
-			exists := acc.MailboxExistsX(tx, "Testbox2")
+			exists, err := acc.MailboxExists(tx, "Testbox2")
+			tcheck(t, err, "checking that mailbox exists")
 			if !exists {
 				t.Fatalf("mailbox does not exist")
 			}
 
-			exists = acc.MailboxExistsX(tx, "Testbox3")
+			exists, err = acc.MailboxExists(tx, "Testbox3")
+			tcheck(t, err, "checking that mailbox does not exist")
 			if exists {
 				t.Fatalf("mailbox does exist")
 			}
 
-			xmb := acc.MailboxFindX(tx, "Testbox3")
+			xmb, err := acc.MailboxFind(tx, "Testbox3")
+			tcheck(t, err, "finding non-existing mailbox")
 			if xmb != nil {
 				t.Fatalf("did find Testbox3: %v", xmb)
 			}
-			xmb = acc.MailboxFindX(tx, "Testbox2")
+			xmb, err = acc.MailboxFind(tx, "Testbox2")
+			tcheck(t, err, "finding existing mailbox")
 			if xmb == nil {
 				t.Fatalf("did not find Testbox2")
 			}
 
-			changes := acc.SubscriptionEnsureX(tx, "Testbox2")
+			changes, err := acc.SubscriptionEnsure(tx, "Testbox2")
+			tcheck(t, err, "ensuring new subscription")
 			if len(changes) == 0 {
 				t.Fatalf("new subscription did not result in changes")
 			}
-			changes = acc.SubscriptionEnsureX(tx, "Testbox2")
+			changes, err = acc.SubscriptionEnsure(tx, "Testbox2")
+			tcheck(t, err, "ensuring already present subscription")
 			if len(changes) != 0 {
 				t.Fatalf("already present subscription resulted in changes")
 			}

store/export.go

@@ -128,7 +128,9 @@ func ExportMessages(log *mlog.Log, db *bstore.DB, accountDir string, archiver Ar
 	name2id := map[string]int64{}
 
 	mailboxes, err := bstore.QueryTx[Mailbox](tx).List()
-	xcheckf(err, "query mailboxes")
+	if err != nil {
+		return fmt.Errorf("query mailboxes: %w", err)
+	}
 	for _, mb := range mailboxes {
 		id2name[mb.ID] = mb.Name
 		name2id[mb.Name] = mb.ID

store/transact.go

@@ -1,24 +0,0 @@
-package store
-
-import (
-	"github.com/mjl-/bstore"
-)
-
-// todo: get rid of this. it's a bad idea to indiscriminately turn all panics into an error.
-func extransact(db *bstore.DB, write bool, fn func(tx *bstore.Tx) error) (rerr error) {
-	defer func() {
-		x := recover()
-		if x == nil {
-			return
-		}
-		if err, ok := x.(error); ok {
-			rerr = err
-		} else {
-			panic(x)
-		}
-	}()
-	if write {
-		return db.Write(fn)
-	}
-	return db.Read(fn)
-}