Add typed JSON output to theme metafields pull

[gonzaloriestra]

Original PR and review history: #8682.

WHY are these changes introduced?

Fixes https://github.com/shop/issues-develop/issues/23694

Metafield downloads need structured outcomes and discoverable JSON support.

WHAT is this pull request doing?

Return strict flattened definitions, absolute artifact paths and explicit success/partial/skipped/cancelled outcomes. Preserve the native owner-keyed metafields.json file, successful downloads and owner-type failures; include a minor changeset for newly added theme JSON flags.

The public output follows docs/cli/json-output.md; explicitly named environments use one {environments: [...]} object.

How to manually test your changes?

shopify theme metafields pull --store example.myshopify.com --json
shopify theme metafields pull --json-schema

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add

[isaacroldan]

The new JSON contract needs to expose the fetch limit.

---

🤖 Generated by the review-pr skill

[isaacroldan]

this could be just a string, to not hardcode a list of values that might change in the future.

[gonzaloriestra]

The public ownerType schema is already a string, so it accepts future upstream values. This map translates the artifact’s keys to API owner types, including variant → PRODUCTVARIANT, and also drives the fetch loop. Replacing it with the raw handle would change the output values. We only fetch the owner types listed here today.

[github-actions]

⚠️ Potential Breaking Changes Detected

This PR contains changes that may break the existing contract.

@shopify/dev_experience — this PR contains breaking changes that require coordination for the next major release.

📦 Major Version Changesets

The following changesets request a major version bump:

Changeset	Package
theme-check-json-contract.md	'@shopify/cli': major
theme-preview-json-contract.md	'@shopify/cli': major
theme-profile-environments.md	'@shopify/cli': major

[github-actions]

Differences in type declarations

We detected differences in the type declarations generated by Typescript for this branch compared to the baseline ('main' branch). Please, review them to ensure they are backward-compatible. Here are some important things to keep in mind:

• Some seemingly private modules might be re-exported through public modules.
• If the branch is behind main you might see odd diffs, rebase main into this branch.

New type declarations

We found no new type declarations in this PR

Existing type declarations

packages/cli-kit/dist/public/node/base-command.d.ts

@@ -21,6 +21,7 @@ declare abstract class BaseCommand extends Command {
     static descriptionWithoutMarkdown(): string | undefined;
     static analyticsNameOverride(): string | undefined;
     static analyticsStopCommand(): string | undefined;
+    private jsonOutputFromFlags;
     catch(error: Error & {
         skipOclifErrorHandling: boolean;
     }): Promise<void>;
@@ -36,6 +37,7 @@ declare abstract class BaseCommand extends Command {
     }, TGlobalFlags extends FlagOutput, TArgs extends ArgOutput>(options?: Input<TFlags, TGlobalFlags, TArgs>, argv?: string[]): Promise<ParserOutput<TFlags, TGlobalFlags, TArgs> & {
         argv: string[];
     }>;
+    protected runWithParsedOutput<T>(flags: FlagOutput, execute: () => T): T;
     protected environmentsFilename(): string | undefined;
     protected parseEnvironmentFlags<TFlags extends FlagOutput, TGlobalFlags extends FlagOutput, TArgs extends ArgOutput>(environment: JsonMap, options: Input<TFlags, TGlobalFlags, TArgs>, explicitFlags: FlagOutput): Promise<FlagOutput>;
     protected validateNonTTYFlags(flags: FlagOutput): void;

packages/cli-kit/dist/cli/api/graphql/admin/generated/metafield_definitions_by_owner_type.d.ts

@@ -2,9 +2,14 @@ import * as Types from './types.js';
 import { TypedDocumentNode as DocumentNode } from '@graphql-typed-document-node/core';
 export type MetafieldDefinitionsByOwnerTypeQueryVariables = Types.Exact<{
     ownerType: Types.MetafieldOwnerType;
+    after?: Types.InputMaybe<Types.Scalars['String']['input']>;
 }>;
 export type MetafieldDefinitionsByOwnerTypeQuery = {
     metafieldDefinitions: {
+        pageInfo: {
+            hasNextPage: boolean;
+            endCursor?: string | null;
+        };
         nodes: {
             key: string;
             name: string;