Add mavmaild, the read-only IMAP poller that feeds mail intake (#246)

The extraction seam landed on the previous branch but nothing fed it. This adds the daemon that does: every interval it opens one mailbox read-only (EXAMINE + BODY.PEEK, so reading leaves no \Seen behind), fetches the UIDs it has not handed over yet, and posts each message to core over ingest_mail. Core runs the model and writes task candidates; this daemon writes nothing and cannot create a reminder. It is a separate daemon because of the credential. mavpoll set the precedent with the zenmoney token (#125): the module talking to the third party holds the secret, reads it from a file so it never lands in argv, in docker-compose.yml or in shell history, and core never sees it. There is deliberately no -password flag, and a test asserts that. Off unless configured at both ends: without -password-file the daemon refuses to start, and if core has no email block the first ingest returns ErrUnknownMethod, which disables the reader instead of hammering a socket that will keep refusing. A seen-UID state file (0600, atomic write) keeps a restart from re-extracting the whole lookback window; correctness does not depend on it, since capture dedupes on normalised text. Logs are counts and UIDs — no subject, sender or body. Verified with an in-process IMAP server and a fake core: bulk mail is filtered before core is asked, seen UIDs are not re-fetched, a failed ingest is retried next poll, ErrUnknownMethod stops at the first message, and state survives a restart. The live half is untested by design — no IMAP credential exists on this box; setup is written up as QA steps. Vikunja #246
2026-08-01 03:13:18 +04:00
parent f42d1594ef
commit ee7bec11e3
9 changed files with 636 additions and 16 deletions
@@ -7,6 +7,7 @@
 /mavpoll
 /mavcaldav
 /mavwaked
+/mavmaild

 # Certs (private keys, don't commit)
 certs/
@@ -36,6 +37,8 @@ deploy/db_key.env
 deploy/telegram.env
 # zenmoney API token, read by mavpoll (never in argv, never committed)
 deploy/zenmoney.token
+# IMAP password, read by mavmaild (never in argv, never committed)
+deploy/imap.password

 # Temp files
 /tmp/
@@ -34,7 +34,7 @@ CGO daemons (`mavend`, `mavsttd`, `mavttsd`, `mavenclient`) need the vendored to
 and libs wired through the Makefile — **do not** call `go build` on them bare, use `make`:

 ```sh
-make build          # all 8 binaries
+make build          # all 9 binaries
 make build-web      # single daemon (pure-Go ones: web/waked/poll/caldav build without CGO)
 make test           # go test -race across ./internal/... ./cmd/... with CGO env set
 ```
@@ -62,6 +62,7 @@ Pure-Go packages (`router`, `memory`, `mavweb`, …) run under a plain `go test
 | `mavenclient` | Voice loop client (mic → stt → core → tts). |
 | `mavpoll` | Telegram long-poll reach. |
 | `mavcaldav` | CalDAV calendar sync. |
+| `mavmaild` | Mail reader (IMAP, read-only). Holds the IMAP password; core never sees it. |

 Daemons are wired socket-to-socket, not linked. `internal/ipc` is the client/server wire
 protocol; the config in `deploy/mavend.json` (with `${VAR}` env expansion from gitignored
@@ -51,7 +51,8 @@ RUN go build -o /out/mavend    ./cmd/mavend    && \
    go build -o /out/mavttsd   ./cmd/mavttsd   && \
    go build -o /out/mavweb    ./cmd/mavweb    && \
    go build -o /out/mavpoll   ./cmd/mavpoll   && \
-    go build -o /out/mavcaldav ./cmd/mavcaldav
+    go build -o /out/mavcaldav ./cmd/mavcaldav && \
+    go build -o /out/mavmaild  ./cmd/mavmaild

 # llama.cpp Vulkan build — the phraser/router LFM engine (llama-server). Built
 # from source (not a prebuilt vendored blob) so the binary's glibc/GLIBCXX match
@@ -20,7 +20,7 @@ PIPER_ESPEAK  := $(shell pwd)/deps/piper/espeak-ng-data

 all: build

-build: build-stt build-tts build-daemon build-client build-waked build-web build-poll build-caldav
+build: build-stt build-tts build-daemon build-client build-waked build-web build-poll build-caldav build-mail

 build-stt:
 	CGO_CFLAGS="$(CGO_CFLAGS)" CGO_LDFLAGS="$(CGO_LDFLAGS)" LD_LIBRARY_PATH="$(shell pwd)/deps/lib" \
@@ -50,6 +50,9 @@ build-poll:
 build-caldav:
 	$(GO) build $(GOFLAGS) -o mavcaldav ./cmd/mavcaldav/

+build-mail:
+	$(GO) build $(GOFLAGS) -o mavmaild ./cmd/mavmaild/
+
 run-web: build-web
 	./mavweb -addr :9200 -voice 127.0.0.1:9100

@@ -185,4 +188,4 @@ download-embedder:
 	@echo '  sudo cp onnxruntime-linux-x64-1.15.1/lib/libonnxruntime.so* /usr/local/lib/'

 clean:
-	rm -f mavend mavenclient mavsttd mavttsd mavweb mavpoll mavcaldav mavwaked
+	rm -f mavend mavenclient mavsttd mavttsd mavweb mavpoll mavcaldav mavwaked mavmaild
@@ -0,0 +1,332 @@
+// mavmaild — the mail reader module (Vikunja #246,
+// docs/plans/01-email-reader.md).
+//
+// Every so often it opens one IMAP mailbox read-only, fetches the messages it
+// has not read yet, and hands each one to core over ipc.MethodIngestMail. Core
+// runs the extraction on the resident model and writes what comes back as task
+// CANDIDATES he reviews on /tasks. Nothing here writes to the store, nothing
+// here can create a reminder, and nothing here speaks.
+//
+// Why a separate daemon rather than a loop inside mavend, when extraction has
+// to happen in mavend anyway: the credential. mavpoll set the precedent with the
+// zenmoney token (#125) — the module that talks to a third party holds the
+// secret, reads it from a FILE so it never appears in `ps`, in
+// docker-compose.yml or in shell history, and core never sees it. Core learns
+// that mail exists only as message text on one IPC method; it cannot connect to
+// the mailbox even if it wanted to, and a compromised core yields no mail
+// password.
+//
+// Off unless configured: without -password-file there is nothing to run, and
+// the daemon says so and exits. If core has no `email` block the very first
+// ingest comes back ErrUnknownMethod and this daemon stops polling instead of
+// hammering a socket that will keep refusing.
+//
+// Mail is personal, so the log is counts and UIDs: how many messages were
+// fetched, how many were bulk, how many candidates came back. No subject, no
+// sender, no body, ever — reviewing a candidate is what /tasks is for.
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"sort"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/kami/maven/internal/email"
+	"github.com/kami/maven/internal/ipc"
+)
+
+func main() {
+	if err := run(os.Args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, "mavmaild:", err)
+		os.Exit(1)
+	}
+}
+
+func run(args []string) error {
+	fs := flag.NewFlagSet("mavmaild", flag.ContinueOnError)
+	socket := fs.String("socket", "", "core IPC socket path (required)")
+	server := fs.String("imap", "", "IMAP server, host or host:993 (required)")
+	user := fs.String("user", "", "IMAP username (required)")
+	passFile := fs.String("password-file", "", "file holding the IMAP password (required — never passed as a flag value)")
+	mailbox := fs.String("mailbox", "INBOX", "mailbox to read, read-only")
+	interval := fs.Duration("interval", 15*time.Minute, "how often to read the mailbox")
+	lookback := fs.Duration("lookback", 72*time.Hour, "how far back to search on each poll")
+	max := fs.Int("max", 25, "most messages to fetch in one poll")
+	timeout := fs.Duration("timeout", 30*time.Second, "IMAP network timeout")
+	statePath := fs.String("state", "", "file remembering which UIDs were read (default: none — every poll re-reads the window)")
+	if err := fs.Parse(args); err != nil {
+		return err
+	}
+	if *socket == "" {
+		return fmt.Errorf("-socket is required")
+	}
+	if *server == "" || *user == "" || *passFile == "" {
+		return fmt.Errorf("mail reading is off unless configured: set -imap, -user and -password-file")
+	}
+
+	// The password is read from a file, never taken as a flag value: an argv
+	// secret is visible in `ps` to every user on the box and lands in the compose
+	// file and the shell history. Read once at start — a rotated password means a
+	// restart, which is cheaper than re-reading his credential every quarter hour.
+	raw, err := os.ReadFile(*passFile)
+	if err != nil {
+		return fmt.Errorf("read password file: %w", err)
+	}
+	password := strings.TrimSpace(string(raw))
+	if password == "" {
+		return fmt.Errorf("password file %s is empty", *passFile)
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	core, err := ipc.DialWait(*socket, 60*time.Second)
+	if err != nil {
+		return err
+	}
+	defer core.Close()
+
+	r := &reader{
+		core:     core,
+		addr:     *server,
+		user:     *user,
+		mailbox:  *mailbox,
+		lookback: *lookback,
+		max:      *max,
+		timeout:  *timeout,
+		state:    newSeenState(*statePath),
+	}
+	if err := r.state.load(); err != nil {
+		// A missing or corrupt state file must not stop mail from being read: the
+		// worst case is re-reading the window, and capture dedupes on text.
+		log.Printf("mavmaild: state: %v (starting from an empty seen-set)", err)
+	}
+
+	// The password is never logged, not even its length.
+	log.Printf("mavmaild: reading %s on %s every %s (lookback %s, max %d/poll)",
+		*mailbox, *server, *interval, *lookback, *max)
+
+	r.pollOnce(ctx, password) // don't idle a full interval on start
+	t := time.NewTicker(*interval)
+	defer t.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			log.Printf("mavmaild: bye")
+			return nil
+		case <-t.C:
+			if r.disabled {
+				// Core told us mail ingestion is not configured. Nothing will change
+				// without a core restart, and a restart restarts us too.
+				log.Printf("mavmaild: core does not accept mail — idling")
+				return nil
+			}
+			r.pollOnce(ctx, password)
+		}
+	}
+}
+
+// mailIngester — the slice of core this daemon uses. One method: hand over a
+// message. It cannot write a fact, create a reminder or read the store, and the
+// interface says so.
+type mailIngester interface {
+	IngestMail(ctx context.Context, req ipc.IngestMailReq) (ipc.IngestMailResp, error)
+}
+
+type reader struct {
+	core     mailIngester
+	addr     string
+	user     string
+	mailbox  string
+	lookback time.Duration
+	max      int
+	timeout  time.Duration
+	state    *seenState
+
+	// dial — connection seam for the tests; nil ⇒ implicit TLS.
+	dial func(addr string, timeout time.Duration) (*email.Conn, error)
+
+	// disabled — core answered ErrUnknownMethod, i.e. it has no email block.
+	disabled bool
+}
+
+// pollOnce — one read of the mailbox, then one ingest per message.
+//
+// A fetch error aborts this poll and nothing else; the next tick tries again.
+// An ingest error for one message does not skip the rest — one mail the model
+// choked on should not hide the four behind it.
+func (r *reader) pollOnce(ctx context.Context, password string) {
+	msgs, err := r.fetch(password)
+	if err != nil {
+		// The error may name a UID; it never names a subject or a sender.
+		log.Printf("mavmaild: fetch: %v", err)
+		if len(msgs) == 0 {
+			return
+		}
+	}
+	var junk, candidates, created int
+	for _, m := range msgs {
+		if ctx.Err() != nil {
+			return
+		}
+		if m.Junk {
+			junk++
+			// Marked seen without a model call: the header filter already decided,
+			// and re-classifying it every quarter hour would be pure waste.
+			r.state.mark(m.UID)
+			continue
+		}
+		resp, err := r.core.IngestMail(ctx, ipc.IngestMailReq{
+			Mailbox: r.mailbox,
+			UID:     m.UID,
+			From:    m.From,
+			Subject: m.Subject,
+			Date:    m.Date,
+			Body:    m.Body,
+		})
+		if errors.Is(err, ipc.ErrUnknownMethod) {
+			log.Printf("mavmaild: core has no email block configured — mail ingestion is off; stopping")
+			r.disabled = true
+			return
+		}
+		if err != nil {
+			// Not marked seen: an ingest that failed should be retried next poll.
+			log.Printf("mavmaild: ingest uid %d: %v", m.UID, err)
+			continue
+		}
+		r.state.mark(m.UID)
+		candidates += len(resp.TaskIDs)
+		created += resp.Created
+	}
+	if err := r.state.save(); err != nil {
+		log.Printf("mavmaild: state: %v", err)
+	}
+	log.Printf("mavmaild: %s: %d read, %d bulk, %d candidate(s), %d new", r.mailbox, len(msgs), junk, candidates, created)
+}
+
+// fetch reads the mailbox. Messages already in the seen-set are not fetched at
+// all, so a steady mailbox costs one SEARCH per poll and nothing else.
+func (r *reader) fetch(password string) ([]email.Message, error) {
+	f := email.FetchSince{
+		Addr:    r.addr,
+		User:    r.user,
+		Mailbox: r.mailbox,
+		Timeout: r.timeout,
+		Since:   time.Now().Add(-r.lookback),
+		Max:     r.max,
+		Skip:    r.state.seen,
+	}
+	return f.RunWith(password, r.dial)
+}
+
+// ---- seen state ------------------------------------------------------------
+
+// seenState — the UIDs already handed to core, persisted so a restart does not
+// re-read (and re-extract, at multi-second LLM cost) the whole lookback window.
+//
+// Correctness does not depend on it: ipc.CaptureTask dedupes on normalised text
+// among live tasks, so a re-read produces no duplicate rows. This exists to save
+// the model's time, which is why a broken state file is a log line rather than a
+// failure.
+//
+// UIDs are per-mailbox and monotonic, so the set is kept as a high-water mark
+// plus the stragglers above it. If the server ever changes UIDVALIDITY, UIDs
+// reset and the window is simply re-read once — dedupe absorbs it.
+type seenState struct {
+	path  string
+	high  uint32
+	set   map[uint32]bool
+	dirty bool
+}
+
+func newSeenState(path string) *seenState {
+	return &seenState{path: path, set: map[uint32]bool{}}
+}
+
+type seenFile struct {
+	High uint32   `json:"high"`
+	UIDs []uint32 `json:"uids,omitempty"`
+}
+
+func (s *seenState) seen(uid uint32) bool {
+	return uid <= s.high || s.set[uid]
+}
+
+func (s *seenState) mark(uid uint32) {
+	if s.seen(uid) {
+		return
+	}
+	s.set[uid] = true
+	s.dirty = true
+	// Advance the high-water mark through any contiguous run, so the explicit set
+	// stays small on a mailbox read in order.
+	for {
+		next := s.high + 1
+		if !s.set[next] {
+			break
+		}
+		delete(s.set, next)
+		s.high = next
+	}
+}
+
+func (s *seenState) load() error {
+	if s.path == "" {
+		return nil
+	}
+	b, err := os.ReadFile(s.path)
+	if errors.Is(err, os.ErrNotExist) {
+		return nil // first run
+	}
+	if err != nil {
+		return err
+	}
+	var f seenFile
+	if err := json.Unmarshal(b, &f); err != nil {
+		return fmt.Errorf("parse %s: %w", s.path, err)
+	}
+	s.high = f.High
+	for _, u := range f.UIDs {
+		s.set[u] = true
+	}
+	return nil
+}
+
+// save writes the state atomically (temp file + rename), 0600: it is a list of
+// message ids from his mailbox, which is metadata about his mail.
+func (s *seenState) save() error {
+	if s.path == "" || !s.dirty {
+		return nil
+	}
+	uids := make([]uint32, 0, len(s.set))
+	for u := range s.set {
+		uids = append(uids, u)
+	}
+	sort.Slice(uids, func(i, j int) bool { return uids[i] < uids[j] })
+	b, err := json.Marshal(seenFile{High: s.high, UIDs: uids})
+	if err != nil {
+		return err
+	}
+	tmp := s.path + ".tmp"
+	if err := os.MkdirAll(filepath.Dir(s.path), 0o700); err != nil {
+		return err
+	}
+	if err := os.WriteFile(tmp, b, 0o600); err != nil {
+		return err
+	}
+	if err := os.Rename(tmp, s.path); err != nil {
+		return err
+	}
+	s.dirty = false
+	return nil
+}
@@ -0,0 +1,254 @@
+package main
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"net"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/kami/maven/internal/email"
+	"github.com/kami/maven/internal/ipc"
+)
+
+// ---- a scripted IMAP server, same shape internal/email's tests use ---------
+
+type fakeIMAP struct {
+	msgs map[uint32]string
+	uids []uint32
+	cmds []string
+}
+
+func (f *fakeIMAP) serve(c net.Conn) {
+	defer c.Close()
+	fmt.Fprint(c, "* OK fake ready\r\n")
+	r := bufio.NewReader(c)
+	for {
+		line, err := r.ReadString('\n')
+		if err != nil {
+			return
+		}
+		parts := strings.SplitN(strings.TrimRight(line, "\r\n"), " ", 2)
+		if len(parts) != 2 {
+			return
+		}
+		tag, cmd := parts[0], parts[1]
+		f.cmds = append(f.cmds, cmd)
+		upper := strings.ToUpper(cmd)
+		switch {
+		case strings.HasPrefix(upper, "LOGIN"), strings.HasPrefix(upper, "EXAMINE"):
+			fmt.Fprintf(c, "%s OK\r\n", tag)
+		case strings.HasPrefix(upper, "UID SEARCH"):
+			var ids []string
+			for _, u := range f.uids {
+				ids = append(ids, strconv.FormatUint(uint64(u), 10))
+			}
+			fmt.Fprintf(c, "* SEARCH %s\r\n%s OK\r\n", strings.Join(ids, " "), tag)
+		case strings.HasPrefix(upper, "UID FETCH"):
+			uid, _ := strconv.ParseUint(strings.Fields(cmd)[2], 10, 32)
+			if raw, ok := f.msgs[uint32(uid)]; ok {
+				fmt.Fprintf(c, "* 1 FETCH (UID %d BODY[] {%d}\r\n%s)\r\n", uid, len(raw), raw)
+			}
+			fmt.Fprintf(c, "%s OK\r\n", tag)
+		case strings.HasPrefix(upper, "LOGOUT"):
+			fmt.Fprintf(c, "* BYE\r\n%s OK\r\n", tag)
+			return
+		default:
+			fmt.Fprintf(c, "%s BAD\r\n", tag)
+		}
+	}
+}
+
+func (f *fakeIMAP) dial(_ string, timeout time.Duration) (*email.Conn, error) {
+	cli, srv := net.Pipe()
+	go f.serve(srv)
+	return email.NewConn(cli, timeout)
+}
+
+// ---- a fake core -----------------------------------------------------------
+
+type fakeCore struct {
+	got  []ipc.IngestMailReq
+	resp ipc.IngestMailResp
+	err  error
+}
+
+func (c *fakeCore) IngestMail(_ context.Context, req ipc.IngestMailReq) (ipc.IngestMailResp, error) {
+	c.got = append(c.got, req)
+	if c.err != nil {
+		return ipc.IngestMailResp{}, c.err
+	}
+	return c.resp, nil
+}
+
+func mail(subject, body string, extraHeaders ...string) string {
+	h := "Subject: " + subject + "\r\nFrom: a@b.c\r\nContent-Type: text/plain; charset=utf-8\r\n"
+	for _, e := range extraHeaders {
+		h += e + "\r\n"
+	}
+	return h + "\r\n" + body + "\r\n"
+}
+
+func newTestReader(t *testing.T, f *fakeIMAP, core *fakeCore, statePath string) *reader {
+	t.Helper()
+	return &reader{
+		core: core, addr: "mail.example:993", user: "kami", mailbox: "INBOX",
+		lookback: 72 * time.Hour, max: 25, timeout: 5 * time.Second,
+		state: newSeenState(statePath),
+		dial:  f.dial,
+	}
+}
+
+func TestPollHandsMessagesToCore(t *testing.T) {
+	f := &fakeIMAP{
+		uids: []uint32{1, 2},
+		msgs: map[uint32]string{
+			1: mail("Счёт", "Оплатить до 5 августа."),
+			2: mail("Скидки", "Sale!", "List-Unsubscribe: <mailto:u@x>"),
+		},
+	}
+	core := &fakeCore{resp: ipc.IngestMailResp{TaskIDs: []int64{1}, Created: 1}}
+	r := newTestReader(t, f, core, "")
+	r.pollOnce(context.Background(), "secret")
+
+	// The newsletter is filtered before core is asked: only the real mail crosses.
+	if len(core.got) != 1 {
+		t.Fatalf("core saw %d messages, want 1 (the bulk one must not cross): %+v", len(core.got), core.got)
+	}
+	got := core.got[0]
+	if got.UID != 1 || got.Mailbox != "INBOX" || got.Subject != "Счёт" {
+		t.Errorf("ingest req = %+v", got)
+	}
+	if !strings.Contains(got.Body, "Оплатить") {
+		t.Errorf("body = %q", got.Body)
+	}
+}
+
+// A second poll must not re-send what core already saw — extraction is a
+// multi-second LLM call per message.
+func TestPollSkipsSeenUIDs(t *testing.T) {
+	f := &fakeIMAP{uids: []uint32{5}, msgs: map[uint32]string{5: mail("Счёт", "текст")}}
+	core := &fakeCore{}
+	r := newTestReader(t, f, core, "")
+	r.pollOnce(context.Background(), "secret")
+	r.pollOnce(context.Background(), "secret")
+	if len(core.got) != 1 {
+		t.Errorf("core saw %d messages over two polls, want 1", len(core.got))
+	}
+}
+
+// An ingest that failed is NOT marked seen: the next poll retries it.
+func TestPollRetriesFailedIngest(t *testing.T) {
+	f := &fakeIMAP{uids: []uint32{5}, msgs: map[uint32]string{5: mail("Счёт", "текст")}}
+	core := &fakeCore{err: fmt.Errorf("llama-server is warming up")}
+	r := newTestReader(t, f, core, "")
+	r.pollOnce(context.Background(), "secret")
+	core.err = nil
+	r.pollOnce(context.Background(), "secret")
+	if len(core.got) != 2 {
+		t.Errorf("core saw %d attempts, want 2 (a failed ingest is retried)", len(core.got))
+	}
+}
+
+// Core without an email block ⇒ stop, don't hammer the socket.
+func TestPollStopsWhenCoreRefusesMail(t *testing.T) {
+	f := &fakeIMAP{uids: []uint32{1, 2}, msgs: map[uint32]string{1: mail("a", "b"), 2: mail("c", "d")}}
+	core := &fakeCore{err: fmt.Errorf("call: %w", ipc.ErrUnknownMethod)}
+	r := newTestReader(t, f, core, "")
+	r.pollOnce(context.Background(), "secret")
+	if !r.disabled {
+		t.Error("ErrUnknownMethod must disable the reader")
+	}
+	if len(core.got) != 1 {
+		t.Errorf("core saw %d messages, want 1 — stop at the first refusal", len(core.got))
+	}
+}
+
+func TestSeenStatePersists(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "state", "seen.json")
+	f := &fakeIMAP{uids: []uint32{9}, msgs: map[uint32]string{9: mail("Счёт", "текст")}}
+	core := &fakeCore{}
+	r := newTestReader(t, f, core, path)
+	r.pollOnce(context.Background(), "secret")
+
+	fi, err := os.Stat(path)
+	if err != nil {
+		t.Fatalf("state file: %v", err)
+	}
+	// A list of message ids from his mailbox is metadata about his mail.
+	if perm := fi.Mode().Perm(); perm != 0o600 {
+		t.Errorf("state file mode = %v, want 0600", perm)
+	}
+
+	// A fresh reader with the same state file must not re-read the message.
+	core2 := &fakeCore{}
+	r2 := newTestReader(t, f, core2, path)
+	if err := r2.state.load(); err != nil {
+		t.Fatalf("load: %v", err)
+	}
+	r2.pollOnce(context.Background(), "secret")
+	if len(core2.got) != 0 {
+		t.Errorf("after a restart core saw %d messages, want 0", len(core2.got))
+	}
+}
+
+func TestSeenStateHighWaterMark(t *testing.T) {
+	s := newSeenState("")
+	s.mark(1)
+	s.mark(3)
+	s.mark(2)
+	if s.high != 3 {
+		t.Errorf("high = %d, want 3 (contiguous run collapses)", s.high)
+	}
+	if len(s.set) != 0 {
+		t.Errorf("explicit set = %v, want empty", s.set)
+	}
+	if !s.seen(2) || s.seen(4) {
+		t.Errorf("seen(2)=%v seen(4)=%v", s.seen(2), s.seen(4))
+	}
+}
+
+func TestSeenStateCorruptFileIsNotFatal(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "seen.json")
+	if err := os.WriteFile(path, []byte("{not json"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	s := newSeenState(path)
+	if err := s.load(); err == nil {
+		t.Error("a corrupt state file should report an error the caller logs")
+	}
+	if s.seen(1) {
+		t.Error("a corrupt state file must leave an empty seen-set, not a poisoned one")
+	}
+}
+
+// Off unless configured, and the credential is never a flag value.
+func TestRunRequiresConfig(t *testing.T) {
+	if err := run([]string{}); err == nil {
+		t.Error("no -socket must be an error")
+	}
+	if err := run([]string{"-socket", "/tmp/nope.sock"}); err == nil {
+		t.Error("no mailbox configuration must be an error, not a default mailbox")
+	}
+	// There is no -password flag at all: only -password-file.
+	if err := run([]string{"-socket", "/x", "-imap", "h", "-user", "u", "-password", "p"}); err == nil ||
+		!strings.Contains(err.Error(), "flag provided but not defined") {
+		t.Errorf("a -password flag must not exist; err = %v", err)
+	}
+}
+
+func TestRunRejectsEmptyPasswordFile(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "pass")
+	if err := os.WriteFile(path, []byte("  \n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	err := run([]string{"-socket", "/x/y.sock", "-imap", "h", "-user", "u", "-password-file", path})
+	if err == nil || !strings.Contains(err.Error(), "empty") {
+		t.Errorf("an empty password file must be refused before dialling; err = %v", err)
+	}
+}
@@ -113,6 +113,31 @@ services:
      - sockets:/run/maven
      # - ./deploy/zenmoney.token:/run/secrets/zenmoney.token:ro

+  # The mail reader (Vikunja #246) is OFF and commented out: it needs an IMAP
+  # account, and there is none on this box. mavmaild reads the password from a
+  # FILE so it never appears in `ps`, in this file, or in shell history — the
+  # same rule mavpoll follows for the zenmoney token. Core never sees the
+  # password: the reader hands core message text on one IPC method, and core
+  # writes what the model extracts as task CANDIDATES he reviews on /tasks.
+  # Nothing here can create a reminder, so a misread mail cannot fire.
+  #
+  # To enable: write the password to deploy/imap.password (0600, gitignored),
+  # add an "email": {} block to deploy/mavend.json, and uncomment this service.
+  # mavmaild:
+  #   <<: *image
+  #   command: ["mavmaild", "-socket", "/run/maven/mavend.sock",
+  #             "-imap", "imap.example.org:993",
+  #             "-user", "kami@example.org",
+  #             "-password-file", "/run/secrets/imap.password",
+  #             "-mailbox", "INBOX",
+  #             "-interval", "15m",
+  #             "-state", "/var/lib/maven/mail-seen.json"]
+  #   depends_on: [mavend]
+  #   volumes:
+  #     - sockets:/run/maven
+  #     - dbdata:/var/lib/maven
+  #     - ./deploy/imap.password:/run/secrets/imap.password:ro
+
 volumes:
  dbdata:
  sockets:
@@ -26,21 +26,23 @@ type FetchSince struct {
 	Since   time.Time
 	Max     int
 	Skip    func(uid uint32) bool
-
-	// dial is the connection seam. nil means Dial (implicit TLS); the tests set
-	// it to an in-process fake. Unexported so no configuration path can point
-	// the reader at a non-TLS transport.
-	dial func(addr string, timeout time.Duration) (*Conn, error)
 }

 // Run performs one read. password is passed here, not stored in the struct, so
 // the configuration of a mailbox and the secret for it are never the same value
 // sitting in the same place.
 func (f FetchSince) Run(password string) ([]Message, error) {
+	return f.RunWith(password, nil)
+}
+
+// RunWith is Run with an explicit connection function, which is how the reader
+// daemon and the tests substitute an in-process server. nil ⇒ Dial, i.e.
+// implicit TLS with certificate verification; there is no configuration path
+// that reaches this, so no deployment can end up talking cleartext IMAP.
+func (f FetchSince) RunWith(password string, dial func(addr string, timeout time.Duration) (*Conn, error)) ([]Message, error) {
 	if f.Addr == "" || f.User == "" || f.Mailbox == "" {
 		return nil, fmt.Errorf("email: mailbox not configured (addr/user/mailbox)")
 	}
-	dial := f.dial
 	if dial == nil {
 		dial = Dial
 	}
@@ -21,13 +21,12 @@ func TestFetchSinceRun(t *testing.T) {
 		Since:   time.Date(2026, 7, 30, 0, 0, 0, 0, time.UTC),
 		Max:     2,
 		Skip:    func(uid uint32) bool { return uid == 3 },
-		dial: func(addr string, timeout time.Duration) (*Conn, error) {
-			cli, srv := net.Pipe()
-			go f.serve(t, srv)
-			return NewConn(cli, timeout)
-		},
 	}
-	msgs, err := fs.Run("secret")
+	msgs, err := fs.RunWith("secret", func(addr string, timeout time.Duration) (*Conn, error) {
+		cli, srv := net.Pipe()
+		go f.serve(t, srv)
+		return NewConn(cli, timeout)
+	})
 	if err != nil {
 		t.Fatalf("run: %v", err)
 	}