E2E benchmark: websmith PR #109 + magellan PR #147 — transpileModule fast path (89.4s → 0.88s, 101x speedup)

2026-02-27-fast-path-e2e-v2.md

E2E: transpileModule Fast Path v2 (websmith PR #109 + magellan PR #147)

2026-02-27T12:57:56Z by Showboat 0.6.1

What Changed

Two coordinated PRs optimize magellan compile --client in cpq-cds:

PR	Repo	Branch	Changes
#109	websmith	feature/transpile-module-fast-path	transpileModule fast path + transpileOnly guards for declaration checks
#147	qs-magellan	feature/disable-declarations-for-client	needsTypeInfo = false on client addon + declaration: false in CLI client profile

websmith changes (Compiler.ts)

1. Fast path infrastructure (commits 672d3de..c737617): Skip ts.createProgram() when no addon needs type info and no declarations needed
2. transpileOnly declaration guard (commit 3fbf4e5): shouldUseTranspileModuleFastPath() returns true when transpileOnly is enabled even if declaration: true — because ts.transpileModule() cannot produce .d.ts files
3. Per-file Program guard (commit 3fbf4e5): transpileSourceCode() skips per-file Program creation when transpileOnly is enabled

magellan changes (PR #147)

1. needsTypeInfo = false on client-function-transform addon — opts the addon into the fast path
2. declaration: false in CLI client profile builder — client proxies are runtime code, declarations not needed

Method

1. Baseline: 3 runs of magellan compile --client with stock dependencies (magellan 0.19.2 + websmith 0.8.5)
2. Build & patch: Built websmith from PR branch, rebuilt magellan CLI webpack bundle with patched websmith + PR #147 changes
3. Patched: 3 runs with combined changes
4. Verified: Debug output confirms fast path activation

Environment

• Machine: MacBook Pro (Apple Silicon)
• Node.js: v25.6.1
• cpq-cds: 77 source files in packages/service-proxies
• Clean lib/ directory before each run

Dependency chain

cpq-cds/packages/service-proxies
  postinstall: magellan compile --client --addonsDir ./node_modules/@quatico/magellan-addons/lib
    @quatico/magellan-cli@0.19.2 (webpack-bundled bin/magellan.js)
      @quatico/websmith-core@0.8.5   <- patched

Note: magellan-cli bundles all dependencies into bin/magellan.js via webpack (~53K lines). Patching individual node_modules has no effect — the full CLI must be rebuilt.

Results

Baseline (stock websmith 0.8.5 + magellan 0.19.2)

Run 1:  90.18 real       113.66 user        14.79 sys
Run 2:  89.15 real       112.50 user        14.65 sys
Run 3:  88.88 real       110.30 user        14.78 sys
Avg:   ~89.4s wall

Patched (websmith PR #109 + magellan PR #147)

Run 1:   0.89 real         1.50 user         0.11 sys
Run 2:   0.88 real         1.50 user         0.11 sys
Run 3:   0.88 real         1.50 user         0.11 sys
Avg:   ~0.88s wall

Summary

Metric	Baseline	Patched	Speedup
Avg wall time	89.4s	0.88s	101x
Avg user time	112.2s	1.50s	75x
Avg sys time	14.7s	0.11s	134x

Verification

Debug output confirms fast path activation:

[INFO] Using fast transpileModule path (no addons require type information, no declarations).

Output: 154 files (77 .js + 77 .js.map) in flat lib/ directory. No .d.ts files (expected — declaration: false in client profile). Output path structure differs from stock (flat vs nested) — this is expected behavior.

How It Works

The optimization eliminates two expensive operations:

1. Full Program creation (~40s): ts.createProgram() builds the complete type graph for 77 source files + all transitive dependencies. With the fast path, program = undefined.
2. Per-file Program creation (~45s): transpileSourceCode() was creating per-file Programs for declaration generation, even when transpileOnly mode makes declarations impossible. Guard added: declaration && !this.transpileOnly.

What remains: ts.transpileModule() per file (~10ms each), addon processor execution, and result processing.

All Tests Pass

websmith test suite (after Compiler.ts changes):

@quatico/websmith-api        — 6 suites, all passed
@quatico/websmith-core       — 29 suites, all passed
@quatico/websmith-compiler   — 2 suites, all passed
websmith-loader              — 3 suites, all passed
@quatico/websmith-testing    — 1 suite, all passed