imorland · Nov 10, 2026 · Nov 10, 2026 · Nov 10, 2026
@@ -85,8 +85,8 @@ export interface DeckColumnField {
   input?: (attrs: { id: string; value: string; onchange: (value: string) => void }) => Mithril.Children;
   /** Converts what the member typed into the stored value; return null to reject it. */
   parse?: (value: string) => string | number | null;
-  /** Shown when `parse` rejects the value. */
-  invalidText?: Mithril.Children;
+  /** Shown when `parse` rejects the value; a function is given what was typed. */
+  invalidText?: Mithril.Children | ((value: string) => Mithril.Children);
 }
 
 /**

@@ -57,12 +57,17 @@ const memberField = (): DeckColumnField => ({
 const memberName = (config: DeckColumnConfig): string =>
   app.store.getById<User>('users', String(config.params.userId))?.displayName() ?? String(config.params.name);
 
-const onlyGambits = (query: string): string | null => {
-  const leftover = app.search.gambits.match('discussions', query, () => {});
+/** The words of a query that no discussion filter takes: plain words, or another resource's filters such as `group:`. */
+const unknownParts = (query: string): string[] => {
+  const matched = new Set<string>();
 
-  return query && !leftover ? query : null;
+  app.search.gambits.match('discussions', query, (gambit, matches, negate, bit) => matched.add(bit));
+
+  return query.split(/\s+/).filter((bit) => bit && !matched.has(bit));
 };
 
+const onlyGambits = (query: string): string | null => (query && !unknownParts(query).length ? query : null);
+
 export function registerDefaultColumnTypes(): void {
   deckColumnTypes.add(
     'all',
@@ -213,7 +218,13 @@ export function registerDefaultColumnTypes(): void {
           // Every extension's registered discussion gambits, as in the search modal.
           gambits: 'discussions',
           parse: onlyGambits,
-          invalidText: app.translator.trans('flarum-deck.forum.add_column.filter_invalid_message'),
+          invalidText: (query: string) => {
+            const unknown = unknownParts(query);
+
+            return unknown.length
+              ? app.translator.trans('flarum-deck.forum.add_column.filter_unknown_message', { count: unknown.length, parts: unknown.join(' ') })
+              : app.translator.trans('flarum-deck.forum.add_column.filter_invalid_message');
+          },
         },
       ],
       createSource: (config) => new DiscussionListSource({ filter: gambitFilters(String(config.params.query)) }),

@@ -268,7 +268,9 @@ export default class AddColumnModal<CustomAttrs extends IAddColumnModalAttrs = I
       const value = field.parse ? field.parse(raw) : raw || null;
 
       if (value === null || value === '') {
-        this.error = field.invalidText ?? app.translator.trans('flarum-deck.forum.add_column.invalid_value_message', { field: field.label });
+        const invalid = typeof field.invalidText === 'function' ? field.invalidText(raw) : field.invalidText;
+
+        this.error = invalid ?? app.translator.trans('flarum-deck.forum.add_column.invalid_value_message', { field: field.label });
         return;
       }
 

@@ -10,7 +10,8 @@ import DeckPickerModal, { type IDeckPickerModalAttrs } from './DeckPickerModal';
 export interface IDeckFilterModalAttrs extends IDeckPickerModalAttrs {
   /** Whether a query can be used, e.g. that it's filters only. */
   accept: (query: string) => boolean;
-  invalidText?: Mithril.Children;
+  /** Shown when `accept` turns the query away; a function is given the query. */
+  invalidText?: Mithril.Children | ((query: string) => Mithril.Children);
   onapply: (query: string) => void;
 }
 
@@ -21,6 +22,8 @@ export interface IDeckFilterModalAttrs extends IDeckPickerModalAttrs {
  */
 export default class DeckFilterModal<CustomAttrs extends IDeckFilterModalAttrs = IDeckFilterModalAttrs> extends DeckPickerModal<CustomAttrs> {
   protected error: Mithril.Children = null;
+  /** The query the error is about; it no longer applies once that changes. */
+  protected rejected: string | null = null;
 
   /**
    * @param resource Whose filters to offer, e.g. 'discussions'.
@@ -31,7 +34,7 @@ export default class DeckFilterModal<CustomAttrs extends IDeckFilterModalAttrs =
       title: Mithril.Children;
       value: string;
       accept: (query: string) => boolean;
-      invalidText?: Mithril.Children;
+      invalidText?: IDeckFilterModalAttrs['invalidText'];
       onapply: (query: string) => void;
     }
   ): void {
@@ -51,7 +54,7 @@ export default class DeckFilterModal<CustomAttrs extends IDeckFilterModalAttrs =
     return [
       super.content(),
       <div className="Modal-footer DeckFilterModal-footer">
-        {this.error && <p className="DeckFilterModal-error">{this.error}</p>}
+        {this.error && this.query().trim() === this.rejected && <p className="DeckFilterModal-error">{this.error}</p>}
         <Button className="Button Button--primary" type="button" onclick={() => this.apply()}>
           {app.translator.trans('flarum-deck.forum.add_column.use_filters_button')}
         </Button>
@@ -87,7 +90,10 @@ export default class DeckFilterModal<CustomAttrs extends IDeckFilterModalAttrs =
     const query = this.query().trim();
 
     if (!this.attrs.accept(query)) {
-      this.error = this.attrs.invalidText ?? null;
+      const invalidText = this.attrs.invalidText;
+
+      this.error = (typeof invalidText === 'function' ? invalidText(query) : invalidText) ?? null;
+      this.rejected = query;
       m.redraw();
       return;
     }

@@ -0,0 +1,54 @@
+import app from 'flarum/forum/app';
+import extractText from 'flarum/common/utils/extractText';
+import deckColumnTypes, { registerDefaultColumnTypes } from '../../../../src/forum/columns/deckColumnTypes';
+import type { DeckColumnField } from '../../../../src/forum/columns/DeckColumnType';
+import { boot, loadDeckTranslations } from '../helpers';
+
+beforeAll(() => {
+  boot();
+  loadDeckTranslations();
+  if (!deckColumnTypes.has('filter')) registerDefaultColumnTypes();
+});
+
+const queryField = (): DeckColumnField => deckColumnTypes.get('filter').fields!().find((field) => field.key === 'query')!;
+
+const invalidText = (value: string): string => {
+  const text = queryField().invalidText;
+
+  return extractText(typeof text === 'function' ? text(value) : text);
+};
+
+describe('the custom filter field', () => {
+  it('takes several filters, negated ones too', () => {
+    expect(queryField().parse!('is:unread -author:normal')).toBe('is:unread -author:normal');
+  });
+
+  // A pasted query can hold tabs or runs of spaces between its filters.
+  it('takes filters separated by any whitespace', () => {
+    expect(queryField().parse!('is:unread \t  -author:normal')).not.toBeNull();
+  });
+
+  it('refuses plain words and filters that aren’t for discussions', () => {
+    expect(queryField().parse!('group:mods is:unread')).toBeNull();
+    expect(queryField().parse!('hello is:unread')).toBeNull();
+  });
+
+  // group: is a filter for members, so "plain words aren't supported" left
+  // people looking for words they hadn't typed.
+  it('names what it couldn’t use', () => {
+    expect(invalidText('group:mods is:unread -author:normal')).toMatch(/^group:mods isn't a filter for discussions\./);
+  });
+
+  // That sentence is what sent people looking for words they hadn't typed.
+  it('doesn’t blame plain words when it names the parts', () => {
+    expect(invalidText('group:mods is:unread')).not.toContain('Plain words');
+  });
+
+  it('names every part it couldn’t use', () => {
+    expect(invalidText('group:mods is:unread hello')).toMatch(/^group:mods hello aren't filters for discussions\./);
+  });
+
+  it('asks for filters when nothing was typed', () => {
+    expect(invalidText('')).toBe(extractText(app.translator.trans('flarum-deck.forum.add_column.filter_invalid_message')));
+  });
+});
@@ -68,6 +68,40 @@ describe('adding a custom filter column', () => {
   });
 });
 
+describe('a value the column type turns away', () => {
+  beforeAll(() => {
+    if (deckColumnTypes.has('test-code')) return;
+
+    deckColumnTypes.add('test-code', {
+      icon: 'fas fa-vial',
+      label: () => 'Code',
+      title: () => 'Code',
+      isAvailable: () => true,
+      fields: () => [{ key: 'code', label: 'Code', parse: (value: string) => (value === 'ok' ? value : null), invalidText: (value: string) => `${value} won't do` }],
+      createSource: () => ({}) as any,
+    });
+  });
+
+  it('shows what the type says about what was typed', () => {
+    setLayout([]);
+
+    m.mount(root, {
+      view: () => m(AddColumnModal, { state: new ModalManagerState(), animateShow: () => {}, animateHide: () => {}, deck: new DeckState() }),
+    });
+
+    [...root.querySelectorAll<HTMLButtonElement>('.AddColumnModal-type')].find((button) => button.textContent?.includes('Code'))!.click();
+    m.redraw.sync();
+
+    const input = root.querySelector<HTMLInputElement>('#AddColumnModal-code')!;
+    input.value = 'nope';
+    input.dispatchEvent(new Event('input', { bubbles: true }));
+    root.querySelector<HTMLFormElement>('form')!.dispatchEvent(new Event('submit', { bubbles: true, cancelable: true }));
+    m.redraw.sync();
+
+    expect(root.querySelector('.AddColumnModal-error')?.textContent).toBe("nope won't do");
+  });
+});
+
 describe('what is already in the deck', () => {
   function mount(deck: DeckState) {
     m.mount(root, {

@@ -55,7 +55,7 @@ class FakeSource {
 /** Filters only, as the custom filter column wants. */
 const filtersOnly = (query: string) => !!query && !app.search.gambits.match('discussions', query, () => {});
 
-function open(query: string) {
+function open(query: string, invalidText: any = 'Filters only, please.') {
   const onapply = jest.fn();
   const animateHide = jest.fn();
   const searchState = new SearchState();
@@ -73,7 +73,7 @@ function open(query: string) {
         onchange: () => {},
         onpick: () => {},
         accept: filtersOnly,
-        invalidText: 'Filters only, please.',
+        invalidText,
         onapply,
       }),
   });
@@ -104,6 +104,30 @@ describe('DeckFilterModal', () => {
     expect(root.querySelector('.DeckFilterModal-error')?.textContent).toBe('Filters only, please.');
   });
 
+  it('can say what was wrong with the query written', () => {
+    open('group:mods is:unread', (query: string) => `Can't use ${query}`);
+
+    useButton().click();
+    m.redraw.sync();
+
+    expect(root.querySelector('.DeckFilterModal-error')?.textContent).toBe("Can't use group:mods is:unread");
+  });
+
+  // It names what was wrong with that query, which no longer holds once edited.
+  it('stops showing the error once the query changes', () => {
+    open('group:mods is:unread', (query: string) => `Can't use ${query}`);
+
+    useButton().click();
+    m.redraw.sync();
+
+    const input = root.querySelector<HTMLInputElement>('.SearchModal-input')!;
+    input.value = 'is:unread';
+    input.dispatchEvent(new Event('input', { bubbles: true }));
+    m.redraw.sync();
+
+    expect(root.querySelector('.DeckFilterModal-error')).toBeNull();
+  });
+
   it('uses the filters on Enter', () => {
     const { onapply } = open('is:unread');
 

@@ -32,6 +32,7 @@ flarum-deck:
       in_deck_badge: In your deck
       in_deck_count_badge: "In your deck ×{count}"
       filter_placeholder: e.g. tag:support is:unread
+      filter_unknown_message: "{count, plural, one {{parts} isn't a filter for discussions.} other {{parts} aren't filters for discussions.}} Use filters such as tag:support or is:unread."
       invalid_value_message: "Please enter a valid value for {field}."
       pick_a_result_message: "Choose a result for {field} from the suggestions."
       submit_button: Add column