Fix M2A display templates from the native picker (#60)

CHANGELOG.md

@@ -5,6 +5,35 @@ All notable changes to the Super Layout Table Extension will be documented in th
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## v0.5.1 — M2A picker templates, field scopes & guard fix (Issue #60)
+
+### Fixed
+- **M2A column displays built with the native picker showed an empty cell.**
+  Rooted at the parent collection, the picker emits field-key-prefixed tokens
+  (`{{treatment.collection}}`, `{{treatment.item:service.name}}`) — not the
+  hand-written `{{item:...}}` form the renderer expected. A shared
+  `stripM2AFieldPrefix` helper now normalises both forms on the query and render
+  sides, so picked templates resolve correctly.
+- **Discriminator-only / non-item templates blanked the whole cell.** A template
+  with no `item:` token (e.g. `{{collection}}`) made the API omit the junction
+  `item`, and a guard then skipped every row as if the item were
+  permission-denied. The guard now distinguishes a not-fetched item
+  (`undefined`) from a genuinely absent one (`null`), so these templates render.
+
+### Added
+- **Parent-row and junction-level fields in M2A templates.** Bare tokens
+  (`{{code}}`) resolve against the parent row and field-prefixed tokens
+  (`{{treatment.sort}}`) against the junction row, alongside the discriminator
+  and per-collection `item:` values. On a name clash the most specific (deepest)
+  token wins. Every token is validated against its target before the request, so
+  an unknown token is dropped instead of 403'ing.
+
+### Refactor
+- M2A junction-row rendering extracted into a pure, unit-tested `buildM2ASegments`
+  helper; `resolveM2ARelation` now also reports the junction collection. The
+  conventional `collection` discriminator token lives in `displayHeuristics` and
+  is shared by the query and render sides so they cannot drift.
+
 ## v0.5.0 — Many-to-Any support (Issue #60)
 
 ### Added

README.md

@@ -37,7 +37,7 @@ Smart image handling with an enlarged hover preview, proper aspect ratios, and a
 Duplicate items with all their relationships and translations. Perfect for creating variations of complex data structures.
 
 ### 🧩 Many-to-Any (M2A) Display
-Render polymorphic Many-to-Any relationships directly in the table. Use the `related-values` display or a per-column template with the `{{item:collection.field}}` syntax — including nested chains like `{{item:partners_catalog.catalog_id.title}}`. Each junction row resolves against its own target collection.
+Render polymorphic Many-to-Any relationships directly in the table — built straight from the native field picker or by hand. Use `{{item:<collection>.<field>}}` for a target's fields (nested chains like `{{item:partners_catalog.catalog_id.title}}` work), `{{collection}}` for the discriminator, and bare tokens like `{{code}}` for parent-row fields. Each junction row resolves against its own target collection.
 
 
 
@@ -164,24 +164,28 @@ sidebar under **Layout Options → Column Displays**:
 3. **Templates** use the `{{ field }}` mustache syntax and may reference related fields
 
 #### Many-to-Any (M2A) templates
-M2A fields are polymorphic — each row points at one of several target collections —
-so their templates use a dedicated `item:` syntax. Tokens are written **relative to
-the field** (do not prefix the field name):
-
-- `{{collection}}` — the name of the row's target collection
-- `{{item:<collection>.<field>}}` — a field on a specific target collection
-- Nested paths are supported, e.g. `{{item:partners_catalog.catalog_id.title}}`
-  (M2A → M2O → value)
-
-Each junction row only resolves the token whose `<collection>` matches its own
+M2A fields are polymorphic — each junction row points at one of several target
+collections. Build the template straight from the **native field picker** (it now
+resolves correctly), or write tokens by hand. Tokens resolve per junction row; on a
+name clash the most specific (deepest) match wins:
+
+- `{{item:<collection>.<field>}}` — a field on a specific target collection;
+  nested paths work, e.g. `{{item:partners_catalog.catalog_id.title}}` (M2A → M2O → value)
+- `{{collection}}` — the name of the row's target collection (the discriminator)
+- The field-key-prefixed forms the picker emits also work, e.g.
+  `{{treatment.collection}}`, `{{treatment.item:service.name}}`, or a junction
+  column like `{{treatment.sort}}`
+- `{{<parentField>}}` — a bare token reads a field on the parent row, e.g.
+  `{{code}}` shows the order's own code next to each item
+
+Each junction row only resolves the item token whose `<collection>` matches its own
 target, so a template can cover every allowed collection at once:
 
 ```
 {{collection}}: {{item:partners_catalog.name}} {{item:service.name}}
 ```
 
-The editor shows the allowed collections and an example for the selected field. A
-bare token (e.g. `{{name}}`) is intentionally dropped for M2A — use the `item:` form.
+The editor shows the allowed collections and an example for the selected field.
 
 ### Bookmarks
 Save table configurations for quick access:

package.json

@@ -1,6 +1,6 @@
 {
   "name": "directus-extension-super-table",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "description": "A powerful and feature-rich table layout extension for Directus 11+ with inline editing, quick filters, and manual sorting",
   "icon": "table_rows",
   "keywords": [

src/components/ColumnDisplayEditor.vue

@@ -24,8 +24,8 @@
         @input="form.template = $event ?? ''"
       />
       <div v-if="m2aHelp" class="hint">
-        Many-to-Any field — use <code>{{ itemToken }}</code> (no
-        <code>{{ m2aHelp.fieldKey }}.</code> prefix).
+        Many-to-Any field — pick fields from the tree, or write
+        <code>{{ itemToken }}</code> by hand.
       </div>
     </div>
 
@@ -103,10 +103,10 @@ const m2aHelp = computed(() => {
     : '{{collection}}: {{item:<collection>.name}}';
   const allowed = collections.length ? `Allowed collections: ${collections.join(', ')}. ` : '';
   const tooltip =
-    `Many-to-Any field. Write tokens relative to the field (no "${rootField}." prefix). ` +
-    `Use ${collectionToken} for the target collection and ${itemToken} for its values. ` +
+    `Many-to-Any field. Pick fields from the template tree, or write tokens by hand: ` +
+    `${collectionToken} for the target collection and ${itemToken} for its values. ` +
     `${allowed}Example: ${example}`;
-  return { fieldKey: rootField, collections, example, tooltip };
+  return { tooltip };
 });
 
 const canSave = computed(() => {

src/components/EditableCellRelational.vue

@@ -192,7 +192,7 @@ import TagCell from './TagCell.vue';
 import { isFieldEditable, getFieldEditWarning, getFieldSupportLevel } from '../utils/fieldSupport';
 import { pickHeuristic, isM2A } from '../utils/displayHeuristics';
 import { resolveM2ARelation } from '../utils/resolveM2ARelation';
-import { renderM2ATemplate } from '../utils/renderM2ATemplate';
+import { buildM2ASegments, isBlockedSegment, type M2ASegment } from '../utils/buildM2ASegments';
 import { resolveTranslationValue } from '../utils/resolveTranslationValue';
 import { usePermissions } from '../composables/usePermissions';
 
@@ -401,16 +401,11 @@ const displayValue = computed(() => {
 
 const isM2AField = computed(() => isM2A(props.field));
 
-// M2A cells render structurally so each junction row can show either its
-// resolved template value or a `block` icon when its target collection is not
-// readable by the current user.
-type M2ASegment = { text: string } | { blocked: true; collection: string };
-
+// M2A cells render structurally (see buildM2ASegments) so each junction row can
+// show either its resolved template value or a `block` icon when its target
+// collection is not readable by the current user.
 const m2aSegments = computed<M2ASegment[]>(() => {
   if (!isM2AField.value) return [];
-  const relationalValue = props.item[props.fieldKey];
-  if (!Array.isArray(relationalValue) || relationalValue.length === 0) return [];
-
   const collection = props.field?.collection;
   const fieldName = props.field?.field;
   const m2a =
@@ -425,27 +420,17 @@ const m2aSegments = computed<M2ASegment[]>(() => {
     props.field?.meta?.display_options?.template ||
     `{{${m2a.discriminator}}}`;
 
-  const segments: M2ASegment[] = [];
-  for (const row of relationalValue) {
-    if (!row || typeof row !== 'object') continue;
-    const rowCollection = row[m2a.discriminator];
-    // Missing item: only a permission denial (not a dangling FK) earns the icon.
-    if (rowCollection && row[m2a.itemField] == null) {
-      if (!permissions.canRead(String(rowCollection))) {
-        segments.push({ blocked: true, collection: String(rowCollection) });
-      }
-      continue;
-    }
-    const text = renderM2ATemplate(row, template, m2a.itemField, m2a.discriminator).trim();
-    if (text && text !== '—') segments.push({ text });
-  }
-  return segments;
+  return buildM2ASegments(
+    props.item[props.fieldKey],
+    template,
+    m2a.itemField,
+    m2a.discriminator,
+    String(fieldName),
+    props.item,
+    (c) => permissions.canRead(c)
+  );
 });
 
-function isBlockedSegment(seg: M2ASegment): seg is { blocked: true; collection: string } {
-  return 'blocked' in seg;
-}
-
 type ResolvedDisplay = {
   display: string | null;
   options: Record<string, unknown>;

src/utils/adjustFieldsForDisplays.ts

@@ -8,6 +8,9 @@ import {
   pickHeuristic,
   parseM2AToken,
   buildM2AFieldPath,
+  isM2APrefix,
+  stripM2AFieldPrefix,
+  M2A_COLLECTION_TOKEN,
 } from './displayHeuristics';
 import { resolveM2ARelation } from './resolveM2ARelation';
 
@@ -160,26 +163,54 @@ export function expandTokensThroughRelation(
   if (isM2A) {
     const m2a = resolveM2ARelation(parentCollection, fieldKey, relationsStore, fieldsStore);
     if (!m2a) return [];
-    const { itemField, discriminator, allowedCollections } = m2a;
+    const { itemField, discriminator, allowedCollections, junctionCollection } = m2a;
 
     // The discriminator is always needed so the renderer knows which target
     // collection each row points at before resolving per-collection tokens.
     const expanded: string[] = [`${fieldKey}.${discriminator}`];
-    for (const tok of tokens) {
-      if (tok === discriminator) continue;
-      // Per-collection M2A token: "item:collection.path". Bare tokens are dropped
-      // on purpose — they would resolve against the wrong collection and 403.
+    const add = (path: string) => {
+      if (!expanded.includes(path)) expanded.push(path);
+    };
+
+    for (const rawTok of tokens) {
+      // The native picker prefixes relation tokens with the field key. A prefix
+      // means a junction/item field; a bare token is a parent-level field.
+      const hadPrefix = rawTok.startsWith(`${fieldKey}.`);
+      const tok = stripM2AFieldPrefix(rawTok, fieldKey);
+      // The discriminator (and its conventional `collection` alias) is always
+      // emitted above; skip so it's never re-emitted as a junction/parent field.
+      if (tok === discriminator || tok === M2A_COLLECTION_TOKEN) continue;
+
+      // Per-collection item token: "item:collection.path".
       const parsed = parseM2AToken(tok);
-      if (!parsed) continue;
-      const { prefix, collection: col, path } = parsed;
-      if (prefix !== itemField && prefix !== 'item') continue;
-      if (allowedCollections.length > 0 && !allowedCollections.includes(col)) continue;
-      // Only the first path segment is validated against the target — deep
-      // leaves are unvalidated, matching the M2M/M2O branches below.
-      const firstSegment = (path.split('.')[0] ?? '') as string;
-      if (!fieldsStore.getField(col, firstSegment)) continue;
-      const expandedPath = buildM2AFieldPath(fieldKey, itemField, col, path);
-      if (!expanded.includes(expandedPath)) expanded.push(expandedPath);
+      if (parsed && isM2APrefix(parsed.prefix, fieldKey, itemField)) {
+        const { collection: col, path } = parsed;
+        if (allowedCollections.length > 0 && !allowedCollections.includes(col)) continue;
+        // Only the first path segment is validated against the target — deep
+        // leaves are unvalidated, matching the M2M/M2O branches below.
+        const firstSegment = (path.split('.')[0] ?? '') as string;
+        if (!fieldsStore.getField(col, firstSegment)) continue;
+        add(buildM2AFieldPath(fieldKey, itemField, col, path));
+        continue;
+      }
+
+      const firstSegment = (tok.split('.')[0] ?? '') as string;
+      if (!firstSegment) continue;
+
+      if (hadPrefix) {
+        // Junction-level field (e.g. `treatment.sort`); validate against the
+        // junction so an unknown token never reaches the API and 403s.
+        if (junctionCollection && fieldsStore.getField(junctionCollection, firstSegment)) {
+          add(`${fieldKey}.${tok}`);
+        }
+        continue;
+      }
+
+      // Bare token → parent-level field (e.g. `code`), fetched at the top level.
+      // Validated against the parent so a stray token is dropped, not 403'd.
+      if (fieldsStore.getField(parentCollection, firstSegment)) {
+        add(tok);
+      }
     }
     return expanded;
   }

src/utils/buildM2ASegments.ts

@@ -0,0 +1,60 @@
+import { renderM2ATemplate } from './renderM2ATemplate';
+
+/**
+ * One rendered M2A junction row: either resolved template text, or a `block`
+ * marker when its target collection is not readable by the current user.
+ */
+export type M2ASegment = { text: string } | { blocked: true; collection: string };
+
+/** Narrow a segment to the blocked variant (for template branching). */
+export function isBlockedSegment(seg: M2ASegment): seg is { blocked: true; collection: string } {
+  return 'blocked' in seg;
+}
+
+/**
+ * Build the per-junction-row segments for an M2A cell.
+ *
+ * The `item` value distinguishes three cases:
+ *  - `null`  → the item is genuinely absent: a permission denial (emit a `block`
+ *    marker when the target can't be read) or a dangling FK (skip the row).
+ *  - `undefined` → the item simply wasn't fetched because the template references
+ *    no item field; render anyway so a discriminator-only template still shows.
+ *  - present (object or scalar FK) → render the template.
+ *
+ * Pure: `canRead` is injected so this is unit-testable without the stores.
+ */
+export function buildM2ASegments(
+  rows: unknown,
+  template: string,
+  itemField: string,
+  discriminator: string,
+  fieldName: string,
+  parentRow: Record<string, any> | null | undefined,
+  canRead: (collection: string) => boolean
+): M2ASegment[] {
+  if (!Array.isArray(rows) || rows.length === 0) return [];
+
+  const segments: M2ASegment[] = [];
+  for (const row of rows) {
+    if (!row || typeof row !== 'object') continue;
+    const rowCollection = (row as Record<string, any>)[discriminator];
+
+    if (rowCollection && (row as Record<string, any>)[itemField] === null) {
+      if (!canRead(String(rowCollection))) {
+        segments.push({ blocked: true, collection: String(rowCollection) });
+      }
+      continue;
+    }
+
+    const text = renderM2ATemplate(
+      row as Record<string, any>,
+      template,
+      itemField,
+      discriminator,
+      fieldName,
+      parentRow
+    ).trim();
+    if (text && text !== '—') segments.push({ text });
+  }
+  return segments;
+}

src/utils/displayHeuristics.ts

@@ -32,6 +32,13 @@ export function parseTemplateTokens(template: string): string[] {
   return [...new Set(fields)];
 }
 
+/**
+ * Conventional token for the M2A discriminator, accepted on both the query and
+ * render sides regardless of the relation's actual `one_collection_field` name
+ * (which it usually is anyway). Kept here so both sides resolve it identically.
+ */
+export const M2A_COLLECTION_TOKEN = 'collection';
+
 /**
  * Grammar for a per-collection M2A template token: `item:collection.path`
  * (e.g. `item:articles.title`). Captures [, prefix, collection, path].
@@ -65,6 +72,30 @@ export function buildM2AFieldPath(
   return `${fieldKey}.${itemField}:${collection}.${path}`;
 }
 
+/**
+ * Whether a token prefix addresses this M2A relation, once any parent field-key
+ * prefix has been stripped (see `stripM2AFieldPrefix`). The polymorphic item
+ * field (`item:col.field`) is the picker/conventional form; the parent field
+ * name is also accepted for hand-written `field:col.field` shorthand.
+ */
+export function isM2APrefix(prefix: string, fieldName: string, itemField: string): boolean {
+  return prefix === fieldName || prefix === itemField || prefix === 'item';
+}
+
+/**
+ * Strip the parent field-key prefix the native display-template picker prepends
+ * to M2A tokens. Rooted at the parent collection (M2A has no single related
+ * collection to root at), the picker emits `treatment.collection` and
+ * `treatment.item:service.name`; stripping `<fieldName>.` makes them field-
+ * relative (`collection`, `item:service.name`), matching a hand-written
+ * template. Returns the token unchanged when it carries no such prefix.
+ */
+export function stripM2AFieldPrefix(token: string, fieldName: string): string {
+  if (!fieldName) return token;
+  const prefix = `${fieldName}.`;
+  return token.startsWith(prefix) ? token.slice(prefix.length) : token;
+}
+
 interface RelationsStoreLike {
   getRelationsForField: (
     collection: string,