fix: Reading json files from project root

[Root3287]

Previously the OpenAPI compiler attempted to require() the config file directly. This caused MODULE_NOT_FOUND errors when using --openapi:config-file option.

This patch:

• Changed require() to fs.readFileSync() with JSON.parse().
• Early Return when file does not exists.

Issue

When compiling my CAP project to openapi, I was getting an issue where compile would crash stating Error: Cannot find module './openapi.json'

Expected Behavour

CDS compiles to openapi using the provided config file.

Actual Behavour

The compilation fails with the attached log.

Environment

• Node: v24.8.0
• NPM: 11.6.0
• OS: Linux arch 6.16.8-arch2-1 SMP PREEMPT_DYNAMIC Sun, 21 Sep 2025 23:19:08 +0000 x86_64 GNU/Linux
• @sap/cds: 9.3.1
• @cap-js/openapi: 1.2.3

Steps to repoduce

1. Start a new project. mkdir cap-test && cd cap-test
2. cds init
3. cds a tiny-sample
4. npm i -D @cap-js/openapi
5. Create file openapi.json in project root with the following content:

{
	"servers": [
		{
			"url": "https://example.com",
			"description": "Example"
		}
	]
}

6. Run DEBUG=all cds compile srv -s all -o docs --to openapi --openapi:config-file ./openapi.json

Logs

[cds] - @sap/cds 9.3.1 loaded: ~/git/cap-test/node_modules/@sap/cds
[cds] - Command resolved: ~/git/cap-test/node_modules/@sap/cds-dk/bin/compile/index.js
[cds.env] - loading config for { context: 'cds', cwd: '~/git/cap-test' }
[cds.env] - checking {
  file: '~/git/cap-test/node_modules/@sap/cds-fiori/.cdsrc.yaml'
}
[cds.env] - checking {
  file: '~/git/cap-test/node_modules/@sap/cds-fiori/.cdsrc.json'
}
[cds.env] - checking {
  file: '~/git/cap-test/node_modules/@sap/cds-fiori/.cdsrc.js'
}
[cds.env] - checking {
  file: '~/git/cap-test/node_modules/@sap/cds-fiori/package.json'
}
[cds.env] - importing ~/git/cap-test/node_modules/@sap/cds-fiori/package.json
[cds.env] - checking { file: '~/.cdsrc.json' }
[cds.env] - checking { file: '~/.cdsrc.js' }
[cds.env] - checking { file: '~/git/cap-test/.cdsrc.yaml' }
[cds.env] - checking { file: '~/git/cap-test/.cdsrc.json' }
[cds.env] - checking { file: '~/git/cap-test/.cdsrc.js' }
[cds.env] - checking { file: '~/git/cap-test/package.json' }
[cds.env] - checking { file: '~/git/cap-test/.cdsrc-private.json' }
[cds.env] - checking { file: '~/git/cap-test/default-env.json' }
[cds.env] - checking { file: '~/git/cap-test/.env' }
[trace] - require cds.compiler  : 39.677ms
[trace] - cds.compile *.cds     : 51.465ms
[trace] - cds.compile 2edm      : 88.209ms
Error: Cannot find module './openapi.json'
Require stack:
- ~/git/cap-test/node_modules/@cap-js/openapi/lib/compile/index.js
- ~/git/cap-test/node_modules/@cap-js/openapi/index.js
- ~/git/cap-test/node_modules/@sap/cds-dk/lib/cds.js
- ~/git/cap-test/node_modules/@sap/cds-dk/lib/index.js
- ~/git/cap-test/node_modules/@sap/cds-dk/bin/cds.js
    at Module._resolveFilename (node:internal/modules/cjs/loader:1420:15)
    at defaultResolveImpl (node:internal/modules/cjs/loader:1058:19)
    at resolveForCJSWithHooks (node:internal/modules/cjs/loader:1063:22)
    at Module._load (node:internal/modules/cjs/loader:1226:37)
    at TracingChannel.traceSync (node:diagnostics_channel:322:14)
    at wrapModuleLoad (node:internal/modules/cjs/loader:244:24)
    at Module.require (node:internal/modules/cjs/loader:1503:12)
    at require (node:internal/modules/helpers:152:16)
    at toOpenApiOptions (~/git/cap-test/node_modules/@cap-js/openapi/lib/compile/index.js:96:27)
    at _getOpenApiForMultipleServices (~/git/cap-test/node_modules/@cap-js/openapi/lib/compile/index.js:38:28) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    '~/git/cap-test/node_modules/@cap-js/openapi/lib/compile/index.js',
    '~/git/cap-test/node_modules/@cap-js/openapi/index.js',
    '~/git/cap-test/node_modules/@sap/cds-dk/lib/cds.js',
    '~/git/cap-test/node_modules/@sap/cds-dk/lib/index.js',
    '~/git/cap-test/node_modules/@sap/cds-dk/bin/cds.js'
  ]
}

[daogrady]

Hi Timothy,

thanks for not only providing a MRE with your bug report, but also including a fix! 💪🎊

Change looks good to me and properly resolves the issue of different path resolution mechanisms between fs.exists and require.
Will happily merge as soon as you can resolve the remaining issues brought up by the CI pipeline.

Best,
Daniel

[daogrady]

Looks good now, thanks for the contribution! 🙂