From 8104c79042bc2998e71bfe3f5e6b556fdbac1b7d Mon Sep 17 00:00:00 2001
From: Omar Ramadan <omar@blockcast.net>
Date: Mon, 18 May 2026 04:01:23 +0000
Subject: [PATCH] fix(sync-gbrain): fall through to filesystem walk when source
 has 0 code pages
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`/sync-gbrain --full` was a silent no-op on sources that had never been
initially synced. The orchestrator's --full path routed to
`gbrain reindex-code`, which only re-chunks existing `type='code'`
pages — it does NOT walk the filesystem (see reindex-code.ts docstring:
"Explicit backfill for v0.19.0 → v0.21.0 brains... walk every page
where type='code'"). For a source with zero code pages, reindex-code
exits 0 with `codePages: 0` and the orchestrator reports success
despite indexing nothing.

Side-by-side proof on the same source ID:

    gbrain sync --strategy code --source <id> --dry-run  -> 14,799 files
    gbrain reindex-code --source <id> --dry-run          -> 0 code page(s)

Fix: probe the source's existing code page count via
`reindex-code --dry-run --json` before deciding the subcommand. If
zero pages (or probe fails), fall through to `sync --strategy code`
which does the filesystem walk via `performFullSync`. Preserves the
v0.21.0 backfill semantics for sources that already have code pages.

Repro:
1. Fresh source: `gbrain sources add my-repo --path ~/my-repo --federated`
2. `/sync-gbrain --full` (or invoke orchestrator directly)
3. Before this fix: completes in ~10s, page_count=0
4. After this fix: walks the filesystem as expected

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 bin/gstack-gbrain-sync.ts | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/bin/gstack-gbrain-sync.ts b/bin/gstack-gbrain-sync.ts
index 732ee430c4..bf0e19bfba 100644
--- a/bin/gstack-gbrain-sync.ts
+++ b/bin/gstack-gbrain-sync.ts
@@ -401,8 +401,32 @@ async function runCodeImport(args: CliArgs): Promise<StageResult> {
     };
   }
 
-  // Step 2: Run sync or reindex.
-  const syncArgs = args.mode === "full"
+  // Step 2: Choose between filesystem walk and existing-page reindex.
+  // `gbrain reindex-code` only re-chunks existing `type='code'` pages — it
+  // does NOT walk the filesystem (see reindex-code.ts docstring). For a
+  // source that has never been initially synced, reindex-code is a silent
+  // no-op. So for --full we first probe the source's existing code page
+  // count; if zero, fall back to `sync --strategy code` which walks the
+  // filesystem via performFullSync. Preserves the v0.21.0 backfill
+  // semantics for sources that already have code pages.
+  let useReindex = false;
+  if (args.mode === "full") {
+    const probe = spawnSync(
+      "gbrain",
+      ["reindex-code", "--source", sourceId, "--dry-run", "--json"],
+      { encoding: "utf-8", timeout: 30_000, stdio: ["ignore", "pipe", "pipe"] },
+    );
+    if (probe.status === 0) {
+      try {
+        const out = JSON.parse(probe.stdout.trim());
+        useReindex = typeof out.codePages === "number" && out.codePages > 0;
+      } catch {
+        // Unparseable JSON → fall through to sync (safe default).
+      }
+    }
+    // Probe failure (non-zero exit) → fall through to sync (safe default).
+  }
+  const syncArgs = useReindex
     ? ["reindex-code", "--source", sourceId, "--yes"]
     : ["sync", "--strategy", "code", "--source", sourceId];