Allow ignoring single fields/errors

[Bluscream]

You have already researched for similar issues?

I hope so

What are you trying to achieve, or the steps to reproduce?

I want to merge all schemas from different API endpoint responses so i can let AI build a OpenAPI spec file for me

import fs from 'fs/promises';
import path from 'path';
import { defaultResolver, mergeSchemas } from '@fastify/merge-json-schemas';

async function getAllJsonFiles(directory) {
  const files = await fs.readdir(directory);
  const jsonFiles = [];

  for (const file of files) {
    const filePath = path.join(directory, file);
    const stats = await fs.stat(filePath);

    if (stats.isDirectory()) {
      jsonFiles.push(...await getAllJsonFiles(filePath));
    } else if (path.extname(file) === '.json') {
      jsonFiles.push(filePath);
    }
  }

  return jsonFiles;
}

async function loadSchema(file) {
  try {
    const content = await fs.readFile(file, 'utf8');
    return JSON.parse(content);
  } catch (error) {
    console.error(`Error loading schema from ${file}:`, error);
    throw error;
  }
}

async function mergeSchemasWithFallback(files) {
  let schemas = [];

  for (const file of files) {
    try {
      const schema = await loadSchema(file);
      
      // Check if the schema has a custom resolver
      if (schema.$ref && !schema.$ref.startsWith('#')) {
        console.log(`Found external reference: ${schema.$ref}`);
        
        // Try to resolve the $ref
        let resolvedRef;
        try {
          resolvedRef = await fs.promises.readFile(schema.$ref, 'utf8');
          resolvedRef = JSON.parse(resolvedRef);
        } catch (error) {
          console.error(`Failed to resolve reference: ${schema.$ref}`, error);
        }
        
        // Merge the resolved schema
        schemas.push(resolvedRef || schema);
      } else {
        schemas.push(schema);
      }
    } catch (error) {
      console.error(`Error processing schema from ${file}:`, error);
    }
  }

  try {
    return mergeSchemas(schemas, { onConflict: "first"});
  } catch (error) {
    console.error('An error occurred during schema merging:', error);
    throw error;
  }
}

async function writeMergedSchemaToFile(mergedSchema) {
  try {
    await fs.writeFile('merged.schema.json', JSON.stringify(mergedSchema, null, 2));
    console.log('Merged schema has been written to merged.schema.json');
  } catch (error) {
    console.error('Error writing merged schema to file:', error);
  }
}

(async () => {
  try {
    const jsonFiles = await getAllJsonFiles(process.cwd());
    
    const mergedSchema = await mergeSchemasWithFallback(jsonFiles);
    
    // Write the merged schema to a file
    await writeMergedSchemaToFile(mergedSchema);

    console.log(JSON.stringify(mergedSchema, null, 2));

  } catch (error) {
    console.error('An error occurred:', error);
  }
})();

What was the result you received?

PS C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\schemas\pietsmiet.de> node ..\..\scripts\merge-schemas.js
An error occurred during schema merging: MergeError [JsonSchemaMergeError]: Failed to merge "type" keyword schemas.
    at hybridArraysIntersection (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\lib\resolvers.js:33:11)
    at _mergeSchemas (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:310:5)
    at mergeProperties (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:208:34)
    at _mergeSchemas (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:310:5)
    at mergeObjects (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:228:34)
    at _mergeSchemas (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:310:5)
    at mergeSchemas (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:353:24)
    at mergeSchemasWithFallback (file:///C:/Users/blusc/AppData/Local/Temp/grayjay-source-pietsmietde/scripts/merge-schemas.js:64:12)
    at async file:///C:/Users/blusc/AppData/Local/Temp/grayjay-source-pietsmietde/scripts/merge-schemas.js:84:26 {
  code: 'JSON_SCHEMA_MERGE_ERROR',
  schemas: [ [ 'null' ], [ 'null' ], [ 'string' ], [ 'string' ], [ 'string' ] ]
}
An error occurred: MergeError [JsonSchemaMergeError]: Failed to merge "type" keyword schemas.
    at hybridArraysIntersection (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\lib\resolvers.js:33:11)
    at _mergeSchemas (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:310:5)
    at mergeProperties (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:208:34)
    at _mergeSchemas (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:310:5)
    at mergeObjects (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:228:34)
    at _mergeSchemas (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:310:5)
    at mergeSchemas (C:\Users\blusc\AppData\Local\Temp\grayjay-source-pietsmietde\node_modules\@fastify\merge-json-schemas\index.js:353:24)
    at mergeSchemasWithFallback (file:///C:/Users/blusc/AppData/Local/Temp/grayjay-source-pietsmietde/scripts/merge-schemas.js:64:12)
    at async file:///C:/Users/blusc/AppData/Local/Temp/grayjay-source-pietsmietde/scripts/merge-schemas.js:84:26 {
  code: 'JSON_SCHEMA_MERGE_ERROR',
  schemas: [ [ 'null' ], [ 'null' ], [ 'string' ], [ 'string' ], [ 'string' ] ]
}

What did you expect?

a merged.schema.json file in my directory

Context

• node version: v22.6.0
• fastify version: "@fastify/merge-json-schemas": "github:fastify/merge-json-schemas"
• os: Windows
• any other relevant information:

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[mcollina]

Thanks for reporting!

Can you provide steps to reproduce? We often need a reproducible example, e.g. some code that allows someone else to recreate your problem by just copying and pasting it. If it involves more than a couple of different file, create a new repository on GitHub and add a link to that.

[Bluscream]

I worked around this problem by generating a whole OpenAPI spec from scratch using a HAR file, which allowed me to extract all response schemas into one file.