feat(functions-compiler): carry the invocation-logs response channel

[yurynix]

Note

Description

Ports the invocation-logs response channel into @base44/functions-compiler. It was added to apper on 14 September 2026 by base44-dev/apper#22656 — feat(builder): test_backend_function returns its own invocation's logs, flag TEST_FUNCTION_RESPONSE_LOGS, commit 9d315265b06 — closing the last behavioural gap between this package and the compiler engine apper runs in production. When the server sets X-B44-Capture-Logs: 1, the per-app router buffers that invocation's own console.* lines on the request store and returns them on the X-B44-Invocation-Logs response header — covering the normal reply, the 404 / init-500 / 503 early returns, and the crash path. Without it, adopting 0.1.0 as-is would compile user workers that silently drop the feature, so this unblocks the apper swap.

Related Issue

None (ports base44-dev/apper#22656; enables retiring apper's in-tree base44-userapp-bundler engine)

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Other (please describe):

Changes Made

• New src/invocation-logs.ts — the injected runtime snippets: CAPTURE_PATCH (per-line buffering with budgets), INVOCATION_LOGS_PATCH (_b44CaptureStore / _b44AttachInvocationLogs / _b44CrashResponse), and ASCII_ESCAPE, plus the header names and caps (40 lines, 6 KB of captured payload, 7 KB response-header budget).
• Console patch (src/worker-entry.ts) — _b44Wrap now formats once and captures the line via _b44Capture before forwarding it to the original sink, so captured and shipped logs cannot diverge.
• Per-app entry generation — buildAppEntrySource injects INVOCATION_LOGS_PATCH, seeds the request store with ..._b44CaptureStore(request), and routes every reply through _b44AttachInvocationLogs (telemetry stays the inner wrap so its header survives); a thrown error answers through _b44CrashResponse, which mirrors the dispatcher's user-exception 500 body but rethrows CPU-limit / subrequest-quota errors so the dispatcher's own classification stands.
• Safety properties baked in — non-ASCII is \\uXXXX-escaped (workerd's headers.set throws above 0xff), overflow is reported as a dropped count rather than hidden, and when the function's own headers leave no room the payload degrades to drop-count-only and then to no header at all, never breaking a response that works with capture off. A silent invocation still gets an empty-list header, so "no header" stays the unambiguous "app has not rebundled" signal.
• Scope — per-function entries are deliberately untouched; the channel is per-app router scope only.
• Tests — new test/invocation-logs.test.ts (12 tests running the real patches in workerd via Miniflare: levels, line cap, byte budget under adversarial escaping, header squeeze, non-ASCII, passthrough of status/body/headers, crash body, quota rethrow) and 3 added assertions in test/worker-entry.test.ts on the generated entry.
• package.json — version 0.1.0 → 0.1.1, since 0.1.0 is already published.

What is verbatim from apper, and what is new

All of it is a port of apper's files at 9d315265b06 (the tip of base44-dev/apper#22656), with four deliberate deltas and nothing else. Every row below is reproducible with a plain diff against that commit.

File	Verbatim?	The delta
test/invocation-logs.test.ts	byte-identical	none
test/worker-entry.test.ts	byte-identical	none
src/invocation-logs.ts	verbatim except 2 lines	MAX_CAPTURED_BYTES and RESPONSE_HEADER_BUDGET lost their export. They are used only inside the module and knip fails the build on unused exports — the same treatment #621 gave four internal types
src/worker-entry.ts	every ported line verbatim except 1	the new import reads from "./invocation-logs.js"; apper's has no extension. This repo resolves NodeNext-style
package.json	new	0.1.0 → 0.1.1, since 0.1.0 is already published

No formatting or restructuring rode along. The diff on src/worker-entry.ts is 8 hunks and every one of them is the feature. The file still differs from apper's copy in .js import extensions, import ordering and Biome line wrapping — all of that is pre-existing from #621 and untouched here.

To repeat the check: pull every line in either copy of worker-entry.ts mentioning ASCII_ESCAPE, CAPTURE_PATCH, INVOCATION_LOGS_PATCH, _b44Wrap, _b44CaptureStore, _b44AttachInvocationLogs or _b44CrashResponse — 20 lines on each side — and diff them. The only difference is the .js extension above.

Nothing was renamed, re-commented or otherwise improved on the way over. The behaviour is apper's; a divergence would be a bug that only surfaces once apper compiles through this package.

Testing

• I have tested these changes locally
• I have added/updated tests as needed
• All tests pass (`npm test`)

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (if applicable)
• My changes generate no new warnings
• I have updated `docs/` (AGENTS.md) if I made architectural changes

How the gap opened

	When
apper commit this package was snapshotted from (b27ce1f6)	2026-09-10 12:11 +03:00
#621 merged here, extracting the engine without the feature	2026-09-14 11:01 +03:00
base44-dev/apper#22656 merged, adding it (9d315265b06)	2026-09-14 11:19 +03:00

Eighteen minutes after the extraction landed, and four days after the commit it was snapshotted from. The extraction was verbatim against a commit that predated the feature, and the feature landed in apper while the extraction was in review — which is exactly why apper cannot adopt 0.1.0: the package's worker-entry.ts is the older one.

While both copies exist, the check before any swap is a directory diff of the two src/ trees, not a read of either changelog.

Additional Notes

• Do not reformat `src/invocation-logs.ts`. Its exported strings are injected verbatim into every compiled user worker, so its text is part of the emitted bytes.
• Behaviour is additive and opt-in per request. With no `X-B44-Capture-Logs` header the store carries no buffer, capture is a no-op, and crashes rethrow exactly as before — verified by two dedicated tests.
• Known gap (documented in-code): lines logged after the response body starts streaming land past the header, the same frame boundary that already drops those events from per-function log views.
• Publishing 0.1.1 is manual. `manual-publish.yml` is hardcoded to `packages/cli` and npm trusted publishing keys on the workflow filename, so this package has no release lane yet; adding one needs its own trusted-publisher registration.
• Test-suite results above (252 tests green, typecheck/lint/knip clean) are as reported by the author's local run — the full suite was not re-executed in this description-generation environment; CI covers it.

---

_{🤖 Generated by Claude | 2026-09-16 17:14 UTC | ddce31b}

[github-actions]

🚀 Package Preview Available!

---

Install this PR's preview build with npm:

npm i @base44-preview/cli@0.1.15-pr.628.ddce31b

Prefer not to change any import paths? Install using npm alias so your code still imports base44:

npm i "base44@npm:@base44-preview/cli@0.1.15-pr.628.ddce31b"

Or add it to your package.json dependencies:

{
  "dependencies": {
    "base44": "npm:@base44-preview/cli@0.1.15-pr.628.ddce31b"
  }
}

• 📦 Preview Package: @base44-preview/cli@0.1.15-pr.628.ddce31b
• 🔗 View this commit on GitHub

---

_{Preview published to npm registry — try new features instantly!}