Added in a check for theme block settings validation

[AribaRajput]

What are you adding in this PR?

First part of #602

Adding in a theme check for checking theme blocks for valid preset setting keys. The preset setting keys (and the presets of any theme block preset settings) must match the settings keys configured in either the preset settings or the nested theme block settings.

Docs PR: https://github.com/Shopify/shopify-dev/pull/51243

What's next? Any followup issues?

The next issue is to add the exact same type of theme check for section files, just with more coverage.

What did you learn?

A lot about presets, sections and theme blocks and how they are configured. That was the trickiest part of all of this (managing the types, knowing how to grab nested information, etc).

Before you deploy

• This PR includes a new checks or changes the configuration of a check
  • I included a minor bump changeset
  • It's in the allChecks array in src/checks/index.ts
  • I ran yarn build and committed the updated configuration files
    • If applicable, I've updated the theme-app-extension.yml config

• I included a minor bump changeset
• My feature is backward compatible

• I included a patch bump changeset

[charlespwd]

Suggested change

	url: 'https://shopify.dev/docs/storefronts/themes/tools/theme-check/checks/preset-key-exists',
	url: 'https://shopify.dev/docs/storefronts/themes/tools/theme-check/checks/valid-block-preset-settings,

[charlespwd]

Is it only theme blocks or just blocks in general?

[AribaRajput]

I think it will validate on any block. I can remove "theme" so its more clear?

[AribaRajput]

Or, whatever block is in the presets settings.

[charlespwd]

yeah I think abstract block would be fine here

[charlespwd]

We need to highlight the node. I don't think it's ok to have 0:0 for this check.

schema has a ast property you can use to find the node. We also have the nodeAtPath util that can give you the AST node for a given "JSONPath"

const schema = await getSchema();
if (!schema) return;
if (isError(schema.validSchema) || isError(schema.ast)) return;

// imagine that we somehow find out that ["presets", 0, "settings", "unknown-id"] is invalid:
// we can report an error like this:
const settingsNode = nodeAtPath(schema.ast, ['presets', 0, 'settings']) as ObjectNode;
if (!settingsNode) throw new Error('Should not be happening');

// This is a PropertyNode | undefined
const propertyNode = settingsNode.children.find((child) => child.key.value === 'unknown-id');
if (!propertyNode) throw new Error('Should not be happening');

context.report({
  message: `...`,
  startIndex: schemaNodeOffset + propertyNode.loc!.start.offset,
  endIndex: schemaNodeOffset + propertyNode.loc!.end.offset,
});

[charlespwd]

Position information can't be ignored for this check. We'll probably need to rewrite it and iterate over each blocks separately rather than push all of them in the same bucket.