fix: save filters whose rules contain */, line breaks or odd header names

The app stores its filter rules as JSON inside a `/* */` comment at the
top of the Sieve script. A `*/` anywhere in a rule name, a value or the
auto-reply text ended that comment early and turned the rest of the
rules into script, and a CR or LF in a rule name did the same to its
`# Rule:` comment. Stalwart (sieve-rs, on 0.16 and 1.0) also accepts
only the letters A-Z, digits, `-` and `_` in a header name. Any of these
made the server refuse the whole script, so saving any filter, and the
auto-reply with it, failed.

- `*/` in the embedded rules is written as `*\/`, which JSON reads back
  as `*/`, so every client parses the rules as before
- the `# Rule:` comment carries the rule name without line breaks, and
  the parser matches the comment back to its rule by that form
- the filter editor trims header names, turns autocorrect off for them
  and refuses to save one the server would reject, with a translated
  message; the generator leaves a rule with such a header name out of
  the script, since dropping only the condition could widen an "all of"
  rule, and keeps it in the stored rules for editing

locales/rn/ar.json

@@ -670,7 +670,8 @@
       "remove_condition": "إزالة الشرط",
       "sieve_editor": {
         "line_count": "{count, plural, zero {# سطر} one {سطر واحد} two {سطران} few {# أسطر} many {# سطرًا} other {# سطر}}"
-      }
+      },
+      "validation_header_name": "أدخل اسم ترويسة لا يحتوي إلا على الأحرف A-Z والأرقام والشرطات والشرطات السفلية، مثل X-Spam-Flag."
     },
     "folders": {
       "account": "الحساب",

locales/rn/ca.json

@@ -670,7 +670,8 @@
       "remove_condition": "Elimina la condició",
       "sieve_editor": {
         "line_count": "{count, plural, one {# línia} other {# línies}}"
-      }
+      },
+      "validation_header_name": "Introduïu un nom de capçalera que només contingui les lletres A-Z, xifres, guions i guions baixos, com ara X-Spam-Flag."
     },
     "folders": {
       "account": "Compte",

locales/rn/cs.json

@@ -670,7 +670,8 @@
       "remove_condition": "Odebrat podmínku",
       "sieve_editor": {
         "line_count": "{count, plural, one {# řádek} few {# řádky} many {# řádku} other {# řádků}}"
-      }
+      },
+      "validation_header_name": "Zadejte název hlavičky, který obsahuje jen písmena A–Z, číslice, pomlčky a podtržítka, například X-Spam-Flag."
     },
     "folders": {
       "account": "Účet",

locales/rn/da.json

@@ -670,7 +670,8 @@
       "remove_condition": "Fjern betingelse",
       "sieve_editor": {
         "line_count": "{count, plural, one {# linje} other {# linjer}}"
-      }
+      },
+      "validation_header_name": "Angiv et headernavn, der kun bruger bogstaverne A-Z, tal, bindestreger og understregninger, f.eks. X-Spam-Flag."
     },
     "folders": {
       "account": "Konto",

locales/rn/de.json

@@ -670,7 +670,8 @@
       "remove_condition": "Bedingung entfernen",
       "sieve_editor": {
         "line_count": "{count, plural, one {# Zeile} other {# Zeilen}}"
-      }
+      },
+      "validation_header_name": "Geben Sie einen Header-Namen ein, der nur die Buchstaben A–Z, Ziffern, Bindestriche und Unterstriche enthält, zum Beispiel X-Spam-Flag."
     },
     "folders": {
       "account": "Konto",

locales/rn/en.json

@@ -683,7 +683,8 @@
       "remove_condition": "Remove condition",
       "sieve_editor": {
         "line_count": "{count, plural, one {# line} other {# lines}}"
-      }
+      },
+      "validation_header_name": "Enter a header name that uses only the letters A-Z, digits, hyphens and underscores, such as X-Spam-Flag."
     },
     "folders": {
       "account": "Account",

locales/rn/es.json

@@ -670,7 +670,8 @@
       "remove_condition": "Eliminar condición",
       "sieve_editor": {
         "line_count": "{count, plural, one {# línea} other {# líneas}}"
-      }
+      },
+      "validation_header_name": "Escribe un nombre de encabezado que solo use las letras A-Z, números, guiones y guiones bajos, por ejemplo X-Spam-Flag."
     },
     "folders": {
       "account": "Cuenta",

locales/rn/fa.json

@@ -670,7 +670,8 @@
       "remove_condition": "حذف شرط",
       "sieve_editor": {
         "line_count": "{count, plural, one {# خط} other {# خط}}"
-      }
+      },
+      "validation_header_name": "نام هدری وارد کنید که فقط از حروف A-Z، رقم، خط تیره و زیرخط تشکیل شده باشد، مانند X-Spam-Flag."
     },
     "folders": {
       "account": "حساب",

locales/rn/fr.json

@@ -670,7 +670,8 @@
       "remove_condition": "Supprimer la condition",
       "sieve_editor": {
         "line_count": "{count, plural, one {# ligne} other {# lignes}}"
-      }
+      },
+      "validation_header_name": "Saisissez un nom d'en-tête composé uniquement des lettres A à Z, de chiffres, de tirets et de tirets bas, par exemple X-Spam-Flag."
     },
     "folders": {
       "account": "Compte",

locales/rn/he.json

@@ -670,7 +670,8 @@
       "remove_condition": "הסר תנאי",
       "sieve_editor": {
         "line_count": "{count, plural, one {שורה אחת} two {שתי שורות} other {# שורות}}"
-      }
+      },
+      "validation_header_name": "הזן שם כותרת שכולל רק את האותיות A-Z, ספרות, מקפים וקווים תחתונים, למשל X-Spam-Flag."
     },
     "folders": {
       "account": "חשבון",

locales/rn/hu.json

@@ -670,7 +670,8 @@
       "remove_condition": "Feltétel eltávolítása",
       "sieve_editor": {
         "line_count": "{count, plural, one {# sor} other {# sor}}"
-      }
+      },
+      "validation_header_name": "Adj meg egy fejlécnevet, amely csak az A–Z betűket, számjegyeket, kötőjeleket és aláhúzásjeleket tartalmazza, például X-Spam-Flag."
     },
     "folders": {
       "account": "Fiók",

locales/rn/it.json

@@ -670,7 +670,8 @@
       "remove_condition": "Rimuovi condizione",
       "sieve_editor": {
         "line_count": "{count, plural, one {# riga} other {# righe}}"
-      }
+      },
+      "validation_header_name": "Inserisci un nome di intestazione che usi solo le lettere A-Z, cifre, trattini e trattini bassi, ad esempio X-Spam-Flag."
     },
     "folders": {
       "account": "Account",

locales/rn/ja.json

@@ -670,7 +670,8 @@
       "remove_condition": "条件を削除",
       "sieve_editor": {
         "line_count": "{count, plural, other {#行}}"
-      }
+      },
+      "validation_header_name": "ヘッダー名には英字（A～Z）、数字、ハイフン、アンダースコアのみを使用してください（例: X-Spam-Flag）。"
     },
     "folders": {
       "account": "アカウント",

locales/rn/ko.json

@@ -670,7 +670,8 @@
       "remove_condition": "조건 제거",
       "sieve_editor": {
         "line_count": "{count, plural, other {#줄}}"
-      }
+      },
+      "validation_header_name": "헤더 이름은 영문자(A-Z), 숫자, 하이픈, 밑줄만 사용해 입력해 주세요(예: X-Spam-Flag)."
     },
     "folders": {
       "account": "계정",

locales/rn/lv.json

@@ -670,7 +670,8 @@
       "remove_condition": "Noņemt nosacījumu",
       "sieve_editor": {
         "line_count": "{count, plural, zero {# rindas} one {# rinda} other {# rindas}}"
-      }
+      },
+      "validation_header_name": "Ievadiet galvenes nosaukumu, kurā ir tikai burti A–Z, cipari, defises un pasvītras, piemēram, X-Spam-Flag."
     },
     "folders": {
       "account": "Konts",

locales/rn/mn.json

@@ -670,7 +670,8 @@
       "remove_condition": "Нөхцөлийг хасах",
       "sieve_editor": {
         "line_count": "{count, plural, one {# мөр} other {# мөр}}"
-      }
+      },
+      "validation_header_name": "Зөвхөн A-Z үсэг, тоо, зураас, доогуур зураас агуулсан толгойн нэр оруулна уу, жишээ нь X-Spam-Flag."
     },
     "folders": {
       "account": "Бүртгэл",

locales/rn/nb.json

@@ -670,7 +670,8 @@
       "remove_condition": "Fjern vilkår",
       "sieve_editor": {
         "line_count": "{count, plural, one {# linje} other {# linjer}}"
-      }
+      },
+      "validation_header_name": "Skriv inn et navn på meldingshode som bare bruker bokstavene A–Z, sifre, bindestreker og understreker, for eksempel X-Spam-Flag."
     },
     "folders": {
       "account": "Konto",

locales/rn/nl.json

@@ -670,7 +670,8 @@
       "remove_condition": "Voorwaarde verwijderen",
       "sieve_editor": {
         "line_count": "{count, plural, one {# regel} other {# regels}}"
-      }
+      },
+      "validation_header_name": "Voer een headernaam in met alleen de letters A-Z, cijfers, koppeltekens en underscores, zoals X-Spam-Flag."
     },
     "folders": {
       "account": "Account",

locales/rn/pl.json

@@ -670,7 +670,8 @@
       "remove_condition": "Usuń warunek",
       "sieve_editor": {
         "line_count": "{count, plural, one {# wiersz} few {# wiersze} many {# wierszy} other {# wiersza}}"
-      }
+      },
+      "validation_header_name": "Wpisz nazwę nagłówka, która zawiera tylko litery A–Z, cyfry, łączniki i podkreślenia, na przykład X-Spam-Flag."
     },
     "folders": {
       "account": "Konto",

locales/rn/pt.json

@@ -670,7 +670,8 @@
       "remove_condition": "Remover condição",
       "sieve_editor": {
         "line_count": "{count, plural, one {# linha} other {# linhas}}"
-      }
+      },
+      "validation_header_name": "Insira um nome de cabeçalho que use apenas as letras A-Z, algarismos, hífens e sublinhados, como X-Spam-Flag."
     },
     "folders": {
       "account": "Conta",

locales/rn/ro.json

@@ -670,7 +670,8 @@
       "remove_condition": "Eliminați condiția",
       "sieve_editor": {
         "line_count": "{count, plural, one {# linie} few {# linii} other {# de linii}}"
-      }
+      },
+      "validation_header_name": "Introduceți un nume de antet care folosește doar literele A–Z, cifre, cratime și liniuțe de subliniere, de exemplu X-Spam-Flag."
     },
     "folders": {
       "account": "Cont",

locales/rn/ru.json

@@ -670,7 +670,8 @@
       "remove_condition": "Удалить условие",
       "sieve_editor": {
         "line_count": "{count, plural, one {# строка} few {# строки} many {# строк} other {# строки}}"
-      }
+      },
+      "validation_header_name": "Введите имя заголовка, состоящее только из латинских букв A–Z, цифр, дефисов и подчёркиваний, например X-Spam-Flag."
     },
     "folders": {
       "account": "Аккаунт",

locales/rn/sk.json

@@ -670,7 +670,8 @@
       "remove_condition": "Odstrániť podmienku",
       "sieve_editor": {
         "line_count": "{count, plural, one {# riadok} few {# riadky} many {# riadka} other {# riadkov}}"
-      }
+      },
+      "validation_header_name": "Zadajte názov hlavičky, ktorý obsahuje iba písmená A – Z, číslice, spojovníky a podčiarkovníky, napríklad X-Spam-Flag."
     },
     "folders": {
       "account": "Účet",

locales/rn/tr.json

@@ -670,7 +670,8 @@
       "remove_condition": "Koşulu kaldır",
       "sieve_editor": {
         "line_count": "{count, plural, one {# satır} other {# satır}}"
-      }
+      },
+      "validation_header_name": "Yalnızca A-Z harfleri, rakamlar, kısa çizgiler ve alt çizgiler içeren bir başlık adı girin; örneğin X-Spam-Flag."
     },
     "folders": {
       "account": "Hesap",

locales/rn/uk.json

@@ -670,7 +670,8 @@
       "remove_condition": "Видалити умову",
       "sieve_editor": {
         "line_count": "{count, plural, one {# рядок} few {# рядки} many {# рядків} other {# рядка}}"
-      }
+      },
+      "validation_header_name": "Введіть назву заголовка, що містить лише латинські літери A–Z, цифри, дефіси та підкреслення, наприклад X-Spam-Flag."
     },
     "folders": {
       "account": "Обліковий запис",

locales/rn/zh-TW.json

@@ -670,7 +670,8 @@
       "remove_condition": "移除條件",
       "sieve_editor": {
         "line_count": "{count, plural, other {# 行}}"
-      }
+      },
+      "validation_header_name": "請輸入僅包含字母 A-Z、數字、連字號和底線的標頭名稱，例如 X-Spam-Flag。"
     },
     "folders": {
       "account": "帳號",

locales/rn/zh.json

@@ -670,7 +670,8 @@
       "remove_condition": "移除条件",
       "sieve_editor": {
         "line_count": "{count, plural, other {# 行}}"
-      }
+      },
+      "validation_header_name": "请输入仅包含字母 A-Z、数字、连字符和下划线的标头名称，例如 X-Spam-Flag。"
     },
     "folders": {
       "account": "账户",

src/components/filters/FilterRuleModal.tsx

@@ -28,6 +28,7 @@ import {
   updateFilterAction,
   withMailboxTarget,
 } from '../../lib/sieve/rule-actions';
+import { isValidSieveHeaderName } from '../../lib/sieve/generator';
 import type { Mailbox } from '../../api/types';
 import type {
   FilterRule,
@@ -197,13 +198,24 @@ export function FilterRuleModal({ visible, rule, mailboxes, onSave, onClose }: F
       .map((cond) => {
         if (isHasAny(cond)) return { ...cond, value: '' };
         if (cond.field === 'size') return cond; // numeric, single-value only
-        if (typeof cond.value !== 'string') return cond; // already structured
-        return { ...cond, value: inputStringToValue(cond.value) };
+        // A keyboard's trailing space is never part of a header name.
+        const named = cond.field === 'header' ? { ...cond, headerName: cond.headerName?.trim() } : cond;
+        if (typeof named.value !== 'string') return named; // already structured
+        return { ...named, value: inputStringToValue(named.value) };
       });
     if (validConditions.length === 0) {
       Alert.alert(t('settings.filters.validation_empty_conditions', 'At least one condition with a value is required'));
       return;
     }
+    // The server refuses the whole filter script over one header name it
+    // can't read (a space, a dot or a colon in it), so say so here.
+    if (validConditions.some((cond) => cond.field === 'header' && !isValidSieveHeaderName(cond.headerName ?? ''))) {
+      Alert.alert(t(
+        'settings.filters.validation_header_name',
+        'Enter a header name that uses only the letters A-Z, digits, hyphens and underscores, such as X-Spam-Flag.',
+      ));
+      return;
+    }
     const validActions = actions
       .map((a) => withMailboxTarget(a, mailboxTargets))
       .filter((a) => !ACTIONS_WITH_VALUE.has(a.type) || a.value?.trim());
@@ -313,6 +325,8 @@ export function FilterRuleModal({ visible, rule, mailboxes, onSave, onClose }: F
                         value={condition.headerName || ''}
                         onChangeText={(v) => updateCondition(index, { headerName: v })}
                         placeholder={t('settings.filters.header_name', 'Header name')}
+                        autoCapitalize="none"
+                        autoCorrect={false}
                       />
                     )}
 

src/lib/sieve/__tests__/generator.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { generateScript } from '../generator';
+import { generateScript, isValidSieveHeaderName } from '../generator';
 import { parseScript } from '../parser';
 import type { FilterRule } from '../types';
 
@@ -471,6 +471,88 @@ describe('generateScript', () => {
     });
   });
 
+  // The rules ride in a `/* */` comment, which the first `*/` ends, and each
+  // rule's code starts with a `# Rule:` comment, which a line break ends.
+  describe('text that could break out of its comment', () => {
+    const tricky = makeRule({
+      id: 'rule-*/',
+      name: 'Newsletters */ and more',
+      conditions: [
+        { field: 'subject', comparator: 'contains', value: ['*/ spam', 'end */ here'] },
+        { field: 'header', comparator: 'is', value: 'a*/b', headerName: 'X-Spam-Flag' },
+      ],
+      actions: [{ type: 'move', value: 'News */ letters' }, { type: 'mark_read' }],
+    });
+    const vacation = { isEnabled: true, subject: 'Away */', textBody: 'Back soon */ really' };
+
+    it('keeps */ inside the metadata comment and reads every value back', () => {
+      const script = generateScript([tricky], vacation);
+
+      // The comment's first */ is its own end marker.
+      const begin = script.indexOf('/* @metadata:begin');
+      expect(script.indexOf('*/', begin)).toBe(script.indexOf('@metadata:end */') + '@metadata:end '.length);
+      const parsed = parseScript(script);
+      expect(parsed.isOpaque).toBe(false);
+      expect(parsed.rules).toEqual([tricky]);
+      expect(parsed.vacation).toEqual(vacation);
+    });
+
+    it('writes an escape that JSON, and so every older client, reads back as */', () => {
+      const script = generateScript([makeRule({ name: 'a */ b' })]);
+
+      const json = script.match(/@metadata:begin\n(.*)\n@metadata:end/)![1];
+      expect(json).toContain('"name":"a *\\/ b"');
+      expect(JSON.parse(json).rules[0].name).toBe('a */ b');
+    });
+
+    it('keeps a line break in a rule name out of the script and still recognises the block', () => {
+      const rule = makeRule({ name: 'Line one\r\nline two\nthree' });
+      const script = generateScript([rule]);
+
+      expect(script).toContain('\n# Rule: Line one line two three\nif ');
+      const parsed = parseScript(script);
+      // Not kept a second time as an external rule.
+      expect(parsed.rules).toEqual([rule]);
+      expect(parseScript(generateScript(parsed.rules, undefined, { externalRequires: parsed.externalRequires })).rules)
+        .toEqual([rule]);
+    });
+  });
+
+  // sieve-rs (Stalwart 0.16 and 1.0) refuses the whole script over one of
+  // these, the auto-reply and every other rule with it.
+  describe('header names the server would refuse', () => {
+    it.each(['X-Spam Flag', 'X-Foo.Bar', 'X-Foo:', 'X-"Quoted"', 'Grüße'])(
+      'skips a rule that tests %j and keeps it in the metadata',
+      (headerName) => {
+        const bad = makeRule({
+          id: 'bad',
+          name: 'Bad',
+          conditions: [{ field: 'header', comparator: 'contains', value: 'yes', headerName }],
+        });
+        const good = makeRule({ id: 'good', name: 'Good' });
+
+        const script = generateScript([bad, good]);
+
+        const code = script.slice(script.indexOf('@metadata:end */'));
+        expect(code).not.toContain('# Rule: Bad');
+        expect(code).toContain('# Rule: Good');
+        expect(parseScript(script).rules).toEqual([bad, good]);
+      },
+    );
+
+    it('accepts letters, digits, hyphens and underscores, blanks around them aside', () => {
+      expect(isValidSieveHeaderName('X-Spam_Flag2')).toBe(true);
+      expect(isValidSieveHeaderName(' X-Spam-Flag ')).toBe(true);
+      expect(isValidSieveHeaderName('')).toBe(false);
+      expect(isValidSieveHeaderName('X Spam')).toBe(false);
+
+      const script = generateScript([makeRule({
+        conditions: [{ field: 'header', comparator: 'contains', value: 'yes', headerName: ' X-Spam-Flag ' }],
+      })]);
+      expect(script).toContain('if header :contains "X-Spam-Flag" "yes" {');
+    });
+  });
+
   describe('round-trip', () => {
     it('preserves rules through generate → parse cycle', () => {
       const rules: FilterRule[] = [

src/lib/sieve/generator.ts

@@ -22,6 +22,29 @@ function escapeString(value: string): string {
   return value.replace(/\\/g, '\\\\').replace(/"/g, '\\"');
 }
 
+// What sieve-rs (Stalwart 0.16 and 1.0) accepts as a header name. Anything
+// else - a space, a dot, a colon - makes the server refuse the whole script.
+const HEADER_NAME = /^[A-Za-z0-9_-]+$/;
+
+/** Whether `name` can go into a Sieve `header` test (surrounding blanks aside). */
+export function isValidSieveHeaderName(name: string): boolean {
+  return HEADER_NAME.test(name.trim());
+}
+
+/**
+ * A rule's name as it appears in its `# Rule:` comment, which ends at the
+ * line break: a CR or LF in the name would have turned the rest of it into
+ * script. The parser matches the comment back to the rule by this form.
+ */
+export function ruleCommentName(name: string): string {
+  return name.replace(/[\r\n]+/g, ' ').trim();
+}
+
+/** A `header` condition whose name the server would refuse. */
+function hasInvalidHeaderName(condition: FilterCondition): boolean {
+  return condition.field === 'header' && !!condition.headerName?.trim() && !isValidSieveHeaderName(condition.headerName);
+}
+
 // Normalise the condition value to a non-empty string array. Single-value
 // conditions stay one-element; arrays are filtered for empty strings.
 function toValueList(value: string | string[]): string[] {
@@ -78,7 +101,7 @@ function generateCondition(condition: FilterCondition): string {
   }
 
   const headerName = field === 'header'
-    ? (condition.headerName || 'X-Unknown')
+    ? (condition.headerName?.trim() || 'X-Unknown')
     : HEADER_MAP[field];
 
   // A field this client does not know (a rule authored by a newer webmail)
@@ -290,7 +313,10 @@ export function generateScript(
   if (options.includeVacation) {
     metadata.includeVacation = true;
   }
-  const metadataJson = JSON.stringify(metadata);
+  // The rules ride in a `/* */` comment, which the first `*/` ends: one in a
+  // rule name or value cut the metadata short and turned the rest into
+  // script. JSON reads `\/` back as `/`, so every client parses it as before.
+  const metadataJson = JSON.stringify(metadata).replace(/\*\//g, '*\\/');
   const lines: string[] = [];
 
   lines.push('/* @metadata:begin');
@@ -334,9 +360,16 @@ export function generateScript(
       console.warn(`[filters] Skipping rule "${rule.name}": empty conditions or actions`);
       continue;
     }
+    // The server would refuse the whole script, every other rule and the
+    // auto-reply with it. Dropping just the condition could widen an "all
+    // of" rule, so the rule sits out; the metadata keeps it for editing.
+    if (rule.conditions.some(hasInvalidHeaderName)) {
+      console.warn(`[filters] Skipping rule "${rule.name}": a header name the server would refuse`);
+      continue;
+    }
 
     lines.push('');
-    lines.push(`# Rule: ${rule.name}`);
+    lines.push(`# Rule: ${ruleCommentName(rule.name)}`);
 
     const conditions = rule.conditions.map(generateCondition);
     let conditionStr: string;

src/lib/sieve/parser.ts

@@ -7,6 +7,7 @@ import type {
   FilterRule,
   VacationSieveConfig,
 } from './types';
+import { ruleCommentName } from './generator';
 
 // Ported from the webmail's lib/sieve/parser.ts. Parses a Sieve script back
 // into structured rules. Bulwark-authored scripts carry an `@metadata` JSON
@@ -838,7 +839,8 @@ export function parseScript(content: string): ParseResult {
       const match = raw.match(/#\s*Rule:\s*(.+?)\s*$/m);
       if (match) {
         const name = match[1].trim();
-        if (bulwarkRules.some(b => b.name === name)) return false;
+        // The comment carries the name without line breaks (ruleCommentName).
+        if (bulwarkRules.some(b => ruleCommentName(b.name) === name)) return false;
       }
       if (/#\s*Vacation auto-reply/i.test(raw)) return false;
       return true;