Search: a paste whose slug starts with '-' or '_' is indexed as paste_<row id> (a Search document id starts with a letter or digit; Search refused -wgXuYn0); the refused id is forgotten, with no tombstone

ddiff --git a/server/search/documents.js b/server/search/documents.js
iindex 4463590..fe7166f 100644
---- a/server/search/documents.js
++++ b/server/search/documents.js
@@@ -21,6 +21,10 @@ const events = require('../events');
  const SCAN_MS = 60 * 1000;
  const REFRESH_MS = 60 * 60 * 1000;
  const SLUG_RE = /^[A-Za-z0-9_-]{1,80}$/;
++// A Search document id starts with a letter or digit (search.index-document@1): a paste whose slug starts
++// with '-' or '_' is indexed as paste_<row id> instead.
++const DOC_ID_RE = /^[A-Za-z0-9][A-Za-z0-9_-]{0,79}$/;
++const pasteDocId = (p) => (DOC_ID_RE.test(String(p.slug || '')) ? p.slug : `paste_${p.id}`);
  
  const iso = (v) => {
      if (!v) return null;
@@@ -93,7 +97,7 @@ function createSearchDocuments({ db }) {
          if (!shot && p.language) facets.syntax = String(p.language).slice(0, 200);
          if (tags.length) facets.tags = tags;
          const doc = {
--            owner: 'community', type: 'paste', id: p.slug, deleted: false, visibility: 'public',
++            owner: 'community', type: 'paste', id: pasteDocId(p), deleted: false, visibility: 'public',
              canonical_url: `${config.baseUrl}/p/${encodeURIComponent(p.slug)}`,
              title: clean(p.title, 500) || (shot ? 'Screenshot' : 'Untitled'),
              summary: clean(p.ai_summary, 4000) || clean(shot ? '' : p.content, 300) || `A ${shot ? 'screenshot' : 'paste'} on OpenVibe.Community.`,
@@@ -129,7 +133,7 @@ function createSearchDocuments({ db }) {
      const publishThread = (threadId) => send('thread', String(threadId), threadDocument(threadId));
      function publishPaste(row) {
          if (!row || !SLUG_RE.test(String(row.slug || ''))) return 'skipped';
--        return send('paste', row.slug, pasteDocument(row));
++        return send('paste', pasteDocId(row), pasteDocument(row));
      }
      const guard = (fn) => { try { fn(); } catch (err) { stats.lastError = err.message; } };
  
@@@ -150,9 +154,12 @@ function createSearchDocuments({ db }) {
          if (!enabled()) return 0;
          const rows = db.prepare('SELECT * FROM pastes').all();
          const seen = new Set();
--        for (const p of rows) { seen.add(p.slug); guard(() => publishPaste(p)); }
++        for (const p of rows) { seen.add(pasteDocId(p)); guard(() => publishPaste(p)); }
          for (const r of db.prepare("SELECT id FROM search_doc_pushes WHERE type = 'paste' AND deleted = 0").all()) {
--            if (!seen.has(r.id)) guard(() => send('paste', r.id, { deleted: true }));
++            if (seen.has(r.id)) continue;
++            // An id Search could never accept (sent before paste_<id> existed): nothing to remove there.
++            if (!DOC_ID_RE.test(r.id)) db.prepare("DELETE FROM search_doc_pushes WHERE type = 'paste' AND id = ?").run(r.id);
++            else guard(() => send('paste', r.id, { deleted: true }));
          }
          return rows.length;
      }
ddiff --git a/test/search-documents.test.js b/test/search-documents.test.js
iindex fa071e4..6ca7ebb 100644
---- a/test/search-documents.test.js
++++ b/test/search-documents.test.js
@@@ -96,5 +96,18 @@ check('the scan finds a paste changed since the last scan; the refresh removes o
      assert.deepStrictEqual(last.payload, { type: 'paste', id: 'green-elk-3', revision: 2 });
  });
  
++check('a slug starting with a dash is indexed as paste_<id> (a document id starts with a letter or digit)', () => {
++    const p = pastes.insertPaste(db, { slug: '-wgXuYn0', owner_subject: USR, type: 'paste', title: 'Dash', content: 'dash body', visibility: 'public' });
++    db.prepare("INSERT INTO search_doc_pushes (type, id, hash, revision) VALUES ('paste', '-wgXuYn0', 'x', 1)").run();
++    assert.strictEqual(docs.publishPaste(db.prepare('SELECT * FROM pastes WHERE id = ?').get(p.id)), 'sent');
++    const ev = index().at(-1); ok(ev);
++    assert.strictEqual(ev.payload.id, `paste_${p.id}`); assert.strictEqual(ev.payload.canonical_url, `${base}/p/-wgXuYn0`);
++    const r = contracts.validate('search.index-document@1', ev.payload); assert.ok(r.valid, JSON.stringify(r.errors));
++    const before = index().length;
++    docs.refresh();
++    assert.ok(!db.prepare("SELECT 1 FROM search_doc_pushes WHERE id = '-wgXuYn0'").get(), 'the unacceptable id is forgotten');
++    assert.ok(!index().slice(before).some((e) => e.payload.id === '-wgXuYn0'), 'and no tombstone is sent for it');
++});
++
  events._reset();
  console.log(`search documents: ${n} checks passed`);