fix(facts): preserve remote fence writes (#3659)

Co-authored-by: gbrain contributor <contributor@example.com>
Co-authored-by: Time Attakc <89218912+time-attack@users.noreply.github.com>

src/core/import-file.ts

@@ -39,6 +39,7 @@ import { normalizeAliasList } from './search/alias-normalize.ts';
 import { isUndefinedTableError, warnOncePerProcess, validateSlug } from './utils.ts';
 import { computeCorpusGeneration } from './contextual-retrieval-service.ts';
 import { runGuardrails } from './guardrails.ts';
+import { FACTS_FENCE_BEGIN, FACTS_FENCE_END, parseFactsFence } from './facts-fence.ts';
 
 /**
  * v0.20.0 Cathedral II Layer 8 D2 — markdown fence extraction helper.
@@ -104,6 +105,27 @@ function fenceTagToPseudoPath(lang: string | undefined): string | null {
  */
 const MAX_FENCES_PER_PAGE = Number.parseInt(process.env.GBRAIN_MAX_FENCES_PER_PAGE || '100', 10);
 
+function extractFactsFenceBlock(body: string): string | null {
+  const beginIdx = body.indexOf(FACTS_FENCE_BEGIN);
+  if (beginIdx === -1) return null;
+  const endIdx = body.indexOf(FACTS_FENCE_END, beginIdx + FACTS_FENCE_BEGIN.length);
+  if (endIdx === -1) return null;
+  return body.slice(beginIdx, endIdx + FACTS_FENCE_END.length);
+}
+
+function replaceOrAppendFactsFence(body: string, fenceBlock: string): string {
+  const beginIdx = body.indexOf(FACTS_FENCE_BEGIN);
+  if (beginIdx !== -1) {
+    const endIdx = body.indexOf(FACTS_FENCE_END, beginIdx + FACTS_FENCE_BEGIN.length);
+    if (endIdx !== -1) {
+      return body.slice(0, beginIdx) + fenceBlock + body.slice(endIdx + FACTS_FENCE_END.length);
+    }
+  }
+
+  const sep = body.endsWith('\n') ? '\n' : '\n\n';
+  return `${body}${sep}## Facts\n\n${fenceBlock}\n`;
+}
+
 /**
  * Walk the marked lexer output and extract recognizable code fences.
  * Returns one ChunkInput per fence whose language tag maps to a grammar
@@ -548,6 +570,26 @@ export async function importFromContent(
   // hash-match skip) and (b) the hash short-circuit below reuses this row.
   const existing = await engine.getPage(slug, sourceId ? { sourceId } : undefined);
 
+  // #2044: remote get_page intentionally strips private facts rows. A
+  // documented get_page -> edit -> put_page round-trip can therefore arrive
+  // with an empty/missing Facts fence even though the existing page still has
+  // canonical fence rows. Preserve the old fence in that narrow case so the
+  // system-of-record markdown is not truncated by the privacy boundary.
+  if (opts.remote === true && existing?.compiled_truth) {
+    const incomingFacts = parseFactsFence(parsed.compiled_truth);
+    const existingFacts = parseFactsFence(existing.compiled_truth);
+    const existingFenceBlock = extractFactsFenceBlock(existing.compiled_truth);
+    if (
+      incomingFacts.facts.length === 0 &&
+      incomingFacts.warnings.length === 0 &&
+      existingFacts.warnings.length === 0 &&
+      existingFacts.facts.length > 0 &&
+      existingFenceBlock
+    ) {
+      parsed.compiled_truth = replaceOrAppendFactsFence(parsed.compiled_truth, existingFenceBlock);
+    }
+  }
+
   // #1035: absence of an explicit frontmatter `type:` on an EXISTING page
   // means "preserve the stored type", not "re-infer". Pre-fix, a round-trip
   // put (get_page → edit body → put_page without `type:`) silently regressed

src/core/pglite-engine.ts

@@ -4309,7 +4309,11 @@ export class PGLiteEngine implements BrainEngine {
                  $14, $15,
                  $16, $17, $18, $19,
                  $20
-               ) RETURNING id`
+               )
+               ON CONFLICT (source_id, source_markdown_slug, row_num)
+               WHERE row_num IS NOT NULL
+               DO NOTHING
+               RETURNING id`
             : `INSERT INTO facts (
                  source_id, entity_slug, fact, kind, visibility, notability, context,
                  valid_from, valid_until, source, source_session, confidence,
@@ -4323,12 +4327,16 @@ export class PGLiteEngine implements BrainEngine {
                  $15, $16,
                  $17, $18, $19, $20,
                  $21
-               ) RETURNING id`,
+               )
+               ON CONFLICT (source_id, source_markdown_slug, row_num)
+               WHERE row_num IS NOT NULL
+               DO NOTHING
+               RETURNING id`,
           embedStr === null
             ? [ctx.source_id, entitySlug, input.fact, kind, visibility, notability, context, validFrom, validUntil, input.source, sourceSession, confidence, embeddedAt, input.row_num, input.source_markdown_slug, claimMetric, claimValue, claimUnit, claimPeriod, eventType]
             : [ctx.source_id, entitySlug, input.fact, kind, visibility, notability, context, validFrom, validUntil, input.source, sourceSession, confidence, embedStr, embeddedAt, input.row_num, input.source_markdown_slug, claimMetric, claimValue, claimUnit, claimPeriod, eventType],
         );
-        out.push(ins.rows[0].id);
+        if (ins.rows[0]) out.push(ins.rows[0].id);
       }
       return out;
     });

src/core/postgres-engine.ts

@@ -4491,9 +4491,13 @@ export class PostgresEngine implements BrainEngine {
             ${input.row_num}, ${input.source_markdown_slug},
             ${claimMetric}, ${claimValue}, ${claimUnit}, ${claimPeriod},
             ${eventType}
-          ) RETURNING id
+          )
+          ON CONFLICT (source_id, source_markdown_slug, row_num)
+          WHERE row_num IS NOT NULL
+          DO NOTHING
+          RETURNING id
         `;
-        out.push(Number(ins[0].id));
+        if (ins[0]) out.push(Number(ins[0].id));
       }
       return out;
     });

test/e2e/system-of-record-invariant.test.ts

@@ -38,11 +38,11 @@ import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 
 import { PGLiteEngine } from '../../src/core/pglite-engine.ts';
-import { importFromFile } from '../../src/core/import-file.ts';
+import { importFromContent, importFromFile } from '../../src/core/import-file.ts';
 import { runExtractCore } from '../../src/commands/extract.ts';
 import { extractTakes } from '../../src/core/cycle/extract-takes.ts';
 import { runExtractFacts } from '../../src/core/cycle/extract-facts.ts';
-import { stripFactsFence } from '../../src/core/facts-fence.ts';
+import { parseFactsFence, stripFactsFence } from '../../src/core/facts-fence.ts';
 
 let engine: PGLiteEngine;
 let brainDir: string;
@@ -305,6 +305,46 @@ describe('get_page privacy strip via stripFactsFence({keepVisibility:["world"]})
     expect(remoteBody).not.toContain('PRIVATE_DETAIL_PROOF');  // remote MCP strips
     expect(remoteBody).toContain('Founded Acme in 2017');       // world fact retained
   });
+
+  test('remote put_page round-trip preserves an existing private-only facts fence', async () => {
+    const slug = 'people/private-only-facts';
+    await importFromContent(engine, slug, `---
+type: person
+title: Private Only Facts
+slug: ${slug}
+---
+
+# Private Only Facts
+
+## Facts
+
+<!--- gbrain:facts:begin -->
+| # | claim | kind | confidence | visibility | notability | valid_from | valid_until | source | context |
+|---|-------|------|------------|------------|------------|------------|-------------|--------|---------|
+| 1 | PRIVATE_ONLY_FACT | preference | 0.9 | private | medium | 2026-07-30 |  | meeting |  |
+<!--- gbrain:facts:end -->
+`, { noEmbed: true, sourceId: 'default' });
+
+    const trusted = await engine.getPage(slug, { sourceId: 'default' });
+    expect(trusted).not.toBeNull();
+    if (!trusted) return;
+
+    const remoteBody = stripFactsFence(trusted.compiled_truth ?? '', { keepVisibility: ['world'] });
+    expect(remoteBody).toContain('gbrain:facts:begin');
+    expect(remoteBody).not.toContain('PRIVATE_ONLY_FACT');
+
+    await importFromContent(engine, slug, `---
+type: person
+title: Private Only Facts
+slug: ${slug}
+---
+
+${remoteBody}`, { noEmbed: true, sourceId: 'default', remote: true });
+
+    const after = await engine.getPage(slug, { sourceId: 'default' });
+    expect(after?.compiled_truth).toContain('PRIVATE_ONLY_FACT');
+    expect(parseFactsFence(after?.compiled_truth ?? '').facts).toHaveLength(1);
+  });
 });
 
 afterAll(() => {

test/insert-facts-batch.test.ts

@@ -5,7 +5,7 @@
  *   - Batch insert N rows persists row_num + source_markdown_slug
  *   - Empty batch is a no-op
  *   - Returns ids in input-order
- *   - v51 partial UNIQUE index rolls back the whole batch on a collision
+ *   - v51 partial UNIQUE index collisions are idempotently skipped
  *   - deleteFactsForPage scopes by (source_id, source_markdown_slug);
  *     never touches other pages or pre-v51 NULL-source_markdown_slug rows
  *   - deleteFactsForPage on an empty page returns deleted:0 (idempotent)
@@ -135,30 +135,26 @@ describe('engine.insertFacts — batch insert', () => {
     });
   });
 
-  test('v51 partial UNIQUE index rolls back the whole batch on collision', async () => {
+  test('v51 partial UNIQUE index collision skips duplicate rows without rolling back the batch', async () => {
     // Seed row #1 first.
     await engine.insertFacts([fixtureFact(1, { fact: 'seeded' })], { source_id: 'default' });
 
-    // Now try to batch-insert rows that include a colliding row_num=1.
-    let threw = false;
-    try {
-      await engine.insertFacts(
-        [
-          fixtureFact(2, { fact: 'second' }),
-          fixtureFact(1, { fact: 'collides' }),  // row_num=1 on same (source_id, source_markdown_slug)
-          fixtureFact(3, { fact: 'third' }),
-        ],
-        { source_id: 'default' },
-      );
-    } catch {
-      threw = true;
-    }
-    expect(threw).toBe(true);
+    // Now try to batch-insert rows that include a colliding row_num=1. The
+    // duplicate is skipped, but the non-conflicting rows still land.
+    const r = await engine.insertFacts(
+      [
+        fixtureFact(2, { fact: 'second' }),
+        fixtureFact(1, { fact: 'collides' }),  // row_num=1 on same (source_id, source_markdown_slug)
+        fixtureFact(3, { fact: 'third' }),
+      ],
+      { source_id: 'default' },
+    );
+    expect(r.inserted).toBe(2);
+    expect(r.ids).toHaveLength(2);
 
-    // Verify the transaction rolled back — only the seeded row should remain.
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    const rows = await (engine as any).db.query('SELECT fact FROM facts ORDER BY id');
-    expect(rows.rows.map((r: { fact: string }) => r.fact)).toEqual(['seeded']);
+    const rows = await (engine as any).db.query('SELECT fact, row_num FROM facts ORDER BY row_num');
+    expect(rows.rows.map((row: { fact: string }) => row.fact)).toEqual(['seeded', 'second', 'third']);
   });
 
   test('different source_markdown_slug values DO NOT collide on the same row_num', async () => {