Add unused translation key check

.changeset/empty-clouds-share.md

@@ -0,0 +1,9 @@
+---
+'@shopify/theme-check-common': minor
+'@shopify/theme-check-node': minor
+'@shopify/theme-language-server-common': patch
+---
+
+Add an `UnusedTranslationKey` check for default locale keys that are not statically referenced.
+
+Use preloaded theme files when collecting translation references for language server diagnostics.

packages/theme-check-common/src/checks/index.ts

@@ -50,6 +50,7 @@ import { UnrecognizedRenderSnippetArguments } from './unrecognized-render-snippe
 import { UnusedAssign } from './unused-assign';
 import { UnsupportedDocTag } from './unsupported-doc-tag';
 import { UnusedDocParam } from './unused-doc-param';
+import { UnusedTranslationKey } from './unused-translation-key';
 import { ValidContentForArguments } from './valid-content-for-arguments';
 import { ValidContentForArgumentTypes } from './valid-content-for-argument-types';
 import { ValidBlockTarget } from './valid-block-target';
@@ -122,6 +123,7 @@ export const allChecks: (LiquidCheckDefinition | JSONCheckDefinition)[] = [
   UnsupportedDocTag,
   UnusedAssign,
   UnusedDocParam,
+  UnusedTranslationKey,
   ValidBlockTarget,
   ValidHTMLTranslation,
   ValidContentForArguments,

packages/theme-check-common/src/checks/unused-translation-key/index.spec.ts

@@ -0,0 +1,373 @@
+import { expect, describe, it } from 'vitest';
+import { check } from '../../test';
+import { UnusedTranslationKey } from '.';
+
+describe('Module: UnusedTranslationKey', () => {
+  it('reports unused default locale keys', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          actions: {
+            add: 'Add',
+            remove: 'Remove',
+          },
+        }),
+        'snippets/cart.liquid': `{{ 'actions.add' | t }}`,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(1);
+    expect(offenses).to.containOffense({
+      check: UnusedTranslationKey.meta.code,
+      message: "Translation key 'actions.remove' is not statically referenced",
+      uri: 'file:///locales/en.default.json',
+    });
+    expect(offenses[0]!).to.suggest(
+      JSON.stringify({
+        actions: {
+          add: 'Add',
+          remove: 'Remove',
+        },
+      }),
+      'Delete unused translation key',
+      {
+        startIndex: 0,
+        endIndex: JSON.stringify({
+          actions: {
+            add: 'Add',
+            remove: 'Remove',
+          },
+        }).length,
+        insert: JSON.stringify({ actions: { add: 'Add' } }, null, 2),
+      },
+    );
+  });
+
+  it('does not report non-default locale keys', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          actions: {
+            add: 'Add',
+          },
+        }),
+        'locales/fr.json': JSON.stringify({
+          actions: {
+            add: 'Ajouter',
+            remove: 'Supprimer',
+          },
+        }),
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(1);
+    expect(offenses[0].uri).to.equal('file:///locales/en.default.json');
+  });
+
+  it('does not report keys referenced with the translate filter', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          actions: {
+            add: 'Add',
+          },
+        }),
+        'snippets/cart.liquid': `{{ 'actions.add' | translate }}`,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(0);
+  });
+
+  it('does not report keys referenced by static append chains', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          products: {
+            product: {
+              add_to_cart: 'Add to cart',
+            },
+          },
+        }),
+        'snippets/product-form.liquid': `
+          {{ 'products.' | append: 'product.' | append: 'add_to_cart' | t }}
+        `,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(0);
+  });
+
+  it('does not report keys below a statically known prefix', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          products: {
+            product: {
+              add_to_cart: 'Add to cart',
+            },
+          },
+          cart: {
+            title: 'Cart',
+          },
+        }),
+        'snippets/product-form.liquid': `{{ 'products.product.' | append: button_state | t }}`,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(1);
+    expect(offenses).to.containOffense("Translation key 'cart.title' is not statically referenced");
+  });
+
+  it('does not report storefront locale keys when a dynamic translation key has no static prefix', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          actions: {
+            add: 'Add',
+          },
+        }),
+        'snippets/cart.liquid': `{{ translation_key | t }}`,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(0);
+  });
+
+  it('does not infer a static prefix from assigned dynamic translation keys', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          actions: {
+            add: 'Add',
+          },
+        }),
+        'snippets/cart.liquid': `
+          {% assign translation_key = 'actions.' | append: action %}
+          {{ translation_key | t }}
+        `,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(0);
+  });
+
+  it('treats pluralization leaves as used when their parent key is referenced', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          cart: {
+            items: {
+              one: '{{ count }} item',
+              other: '{{ count }} items',
+            },
+          },
+        }),
+        'snippets/cart.liquid': `{{ 'cart.items' | t: count: cart.item_count }}`,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(0);
+  });
+
+  it('does not report schema locale keys referenced by schema t-prefixed values', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.schema.json': JSON.stringify({
+          sections: {
+            header: {
+              name: 'Header',
+              settings: {
+                title: {
+                  label: 'Title',
+                  info: 'Info',
+                },
+              },
+            },
+          },
+        }),
+        'sections/header.liquid': `
+          {% schema %}
+          {
+            "name": "t:sections.header.name",
+            "settings": [
+              {
+                "type": "text",
+                "id": "title",
+                "label": "t:sections.header.settings.title.label"
+              }
+            ]
+          }
+          {% endschema %}
+        `,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(1);
+    expect(offenses).to.containOffense(
+      "Translation key 'sections.header.settings.title.info' is not statically referenced",
+    );
+  });
+
+  it('does not report schema locale keys referenced by settings_schema.json t-prefixed values', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.schema.json': JSON.stringify({
+          theme_settings: {
+            colors: {
+              name: 'Colors',
+              accent: {
+                label: 'Accent',
+                info: 'Choose an accent color',
+              },
+            },
+          },
+        }),
+        'config/settings_schema.json': JSON.stringify([
+          {
+            name: 't:theme_settings.colors.name',
+            settings: [
+              {
+                type: 'color',
+                id: 'accent',
+                label: 't:theme_settings.colors.accent.label',
+              },
+            ],
+          },
+        ]),
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(1);
+    expect(offenses).to.containOffense(
+      "Translation key 'theme_settings.colors.accent.info' is not statically referenced",
+    );
+  });
+
+  it('does not count schema translation references as storefront locale references', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          sections: {
+            header: {
+              name: 'Header',
+            },
+          },
+        }),
+        'locales/en.default.schema.json': JSON.stringify({
+          sections: {
+            header: {
+              name: 'Header',
+            },
+          },
+        }),
+        'sections/header.liquid': `
+          {% schema %}
+          {
+            "name": "t:sections.header.name"
+          }
+          {% endschema %}
+        `,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(1);
+    expect(offenses).to.containOffense({
+      message: "Translation key 'sections.header.name' is not statically referenced",
+      uri: 'file:///locales/en.default.json',
+    });
+  });
+
+  it('still reports schema locale keys when a storefront dynamic key has no static prefix', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          actions: {
+            add: 'Add',
+          },
+        }),
+        'locales/en.default.schema.json': JSON.stringify({
+          sections: {
+            header: {
+              name: 'Header',
+              settings: {
+                title: {
+                  label: 'Title',
+                },
+              },
+            },
+          },
+        }),
+        'snippets/cart.liquid': `{{ translation_key | t }}`,
+        'sections/header.liquid': `
+          {% schema %}
+          {
+            "name": "t:sections.header.name"
+          }
+          {% endschema %}
+        `,
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(1);
+    expect(offenses).to.containOffense({
+      message:
+        "Translation key 'sections.header.settings.title.label' is not statically referenced",
+      uri: 'file:///locales/en.default.schema.json',
+    });
+  });
+
+  it('ignores configured translation key patterns', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          dynamic: {
+            managed_elsewhere: 'Managed elsewhere',
+          },
+        }),
+      },
+      [UnusedTranslationKey],
+      {},
+      {
+        UnusedTranslationKey: {
+          enabled: true,
+          ignoreKeys: ['dynamic.*'],
+        },
+      },
+    );
+
+    expect(offenses).to.have.length(0);
+  });
+
+  it('ignores Shopify-provided translation key namespaces by default', async () => {
+    const offenses = await check(
+      {
+        'locales/en.default.json': JSON.stringify({
+          shopify: {
+            sentence: {
+              words_connector: ', ',
+            },
+          },
+          customer_accounts: {
+            sign_in: 'Sign in',
+          },
+        }),
+      },
+      [UnusedTranslationKey],
+    );
+
+    expect(offenses).to.have.length(0);
+  });
+});