fix: suppress $batch path for REST services

[daogrady]

Fixes #192

The field is specifc for odata and should therefore not be produced for other protocols (REST, specifically):
https://docs.oasis-open.org/odata/odata/v4.0/errata03/os/complete/part1-protocol/odata-v4.0-errata03-os-part1-protocol-complete.html#_Toc453752313

[tim-sh]

Looks good to me.

I just found one gap: in REST-collection GETs we still have the OData query options $filter, $top, $skip, $select, $count, $search, $orderby, whereas CAP's REST adapter doesn't support them. So docs still show unsupported features (as with /$batch).

[daogrady]

Fair observation. I adjusted the output accordingly.

[tim-sh]

$batch suppression is correct (returns 404 on POST and GET; confirmed with a live REST service).

But I made a mistake earlier in terms of the query-option suppression (statement wasn't verified at runtime). The REST adapter does support all eight options, so dropping them removes valid docs. Let's keep only the $batch change and revert the query options (i.e. the second CHANGELOG bullet, the isODataProtocol guard, and the associated test).

This repro checks both cases in one go:

repro.mjs – Node, no deps, run with node repro.mjs

#!/usr/bin/env node
// PR #194 repro: real CAP REST service on in-memory sqlite. Asserts /$batch -> 404
// (claim correct) and that all eight OData query options work end-to-end (claim wrong).
import { spawn } from 'node:child_process';
import { mkdtemp, writeFile, mkdir, rm } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import net from 'node:net';

const freePort = () =>
  new Promise((resolve, reject) => {
    const srv = net.createServer();
    srv.on('error', reject);
    srv.listen(0, () => {
      const { port } = srv.address();
      srv.close(() => resolve(port));
    });
  });

const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

function killTree(child) {
  if (!child || child.exitCode !== null || child.signalCode !== null) return;
  if (process.platform === 'win32') {
    spawn('taskkill', ['/pid', String(child.pid), '/T', '/F'], { stdio: 'ignore' });
  } else {
    try {
      process.kill(-child.pid, 'SIGTERM');
    } catch {
      /* group already gone */
    }
  }
}

async function main() {
  const app = await mkdtemp(join(tmpdir(), 'claim-repro-'));
  const port = await freePort();
  let server;
  const cleanup = async () => {
    killTree(server);
    await rm(app, { recursive: true, force: true });
  };
  process.on('exit', () => killTree(server));

  try {
    await mkdir(join(app, 'db', 'data'), { recursive: true });
    await mkdir(join(app, 'srv'), { recursive: true });

    await writeFile(
      join(app, 'db', 'schema.cds'),
      `namespace my;
entity Authors { key ID : Integer; name : String;
  books : Association to many Books on books.author = $self; }
entity Books { key ID : Integer; title : String; stock : Integer;
  author : Association to Authors; }
`,
    );
    await writeFile(
      join(app, 'srv', 'cat.cds'),
      `using my from '../db/schema';
@path: '/rest/books'
@protocol: 'rest'
service RestService {
  entity Books   as projection on my.Books;
  entity Authors as projection on my.Authors;
}
`,
    );
    await writeFile(join(app, 'db', 'data', 'my-Authors.csv'), 'ID,name\n1,Austen\n2,Tolkien\n');
    await writeFile(
      join(app, 'db', 'data', 'my-Books.csv'),
      'ID,title,stock,author_ID\n1,Alpha,10,1\n2,Beta,20,2\n3,Gamma,30,1\n',
    );
    await writeFile(
      join(app, '.cdsrc.json'),
      JSON.stringify({ requires: { db: { kind: 'sqlite', credentials: { url: ':memory:' } } } }),
    );

    console.log(`## building & starting REST service on :${port} (cds-dk 10.x) ...`);
    server = spawn('npx', ['cds', 'run', '--port', String(port), '--in-memory'], {
      cwd: app,
      detached: process.platform !== 'win32',
      stdio: 'ignore',
    });

    const base = `http://localhost:${port}/rest/books`;
    const ready = async () => {
      try {
        const r = await fetch(`${base}/Books`);
        return (await r.text()).includes('Alpha');
      } catch {
        return false;
      }
    };
    let up = false;
    for (let i = 0; i < 60 && !(up = await ready()); i++) await sleep(500);
    if (!up) {
      console.error(`ABORT: data not available at ${base}/Books – server did not deploy cleanly`);
      process.exitCode = 2;
      return;
    }

    let pass = 0;
    let fail = 0;
    const get = async (q) => (await fetch(`${base}/Books${q}`)).text();
    const check = (label, needle, got) => {
      if (got.includes(needle)) {
        console.log(`PASS  ${label}`);
        pass++;
      } else {
        console.log(`FAIL  ${label}  (expected to contain: ${needle} | got: ${got})`);
        fail++;
      }
    };

    console.log('\n## Claim A: /$batch returns 404 on a REST service');
    const post = await fetch(`${base}/$batch`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: '{}',
    });
    const batchGet = await fetch(`${base}/$batch`);
    check('$batch POST -> 404', '404', String(post.status));
    check('$batch GET  -> 404', '404', String(batchGet.status));

    console.log('\n## Claim B: collection GET honours all eight OData query options');
    check('$top=2', '"ID":1', await get('?$top=2'));
    check('$top=2 excludes 3rd', 'ok', (await get('?$top=2')).includes('Gamma') ? 'HASGAMMA' : 'ok');
    check('$skip=1 drops Alpha', 'Beta', await get('?$skip=1'));
    check('$filter stock gt 15', 'Beta', await get('?$filter=stock%20gt%2015'));
    check('$filter excludes Alpha', 'ok', (await get('?$filter=stock%20gt%2015')).includes('Alpha') ? 'HAS' : 'ok');
    check('$select=title', '"title":"Alpha"', await get('?$select=title'));
    check('$orderby=stock desc', '"title":"Gamma"', await get('?$orderby=stock%20desc'));
    check('$count=true', '"count":3', await get('?$count=true'));
    check('$search=Alpha', 'Alpha', await get('?$search=Alpha'));
    check('$expand=author', '"name":"Austen"', await get('?$expand=author'));
    check('$expand nested $select', '"author":{"name"', await get('?$expand=author($select=name)&$top=1'));
    check('combined filter+ob+top', '"title":"Gamma"', await get('?$filter=stock%20gt%205&$orderby=stock%20desc&$top=2'));

    console.log(`\n## result: ${pass} passed, ${fail} failed  (cds-dk 10.x, runtime via npx cds)`);
    process.exitCode = fail === 0 ? 0 : 1;
  } finally {
    await cleanup();
  }
}

main();