perry compile silently produces wrong output when import resolves through namespace re-export (export * as X from ...) #310

What happened

When user code does import { X } from "pkg" and the package's entry point re-exports X via the namespace form export * as X from "./X.js", Perry's module collector does not traverse the re-export. The compile succeeds, the binary links cleanly, and every property access on X (e.g. X.someFn(...)) silently returns 0 — Perry's "unknown identifier" lowering fallback. There is no warning that X.someFn was unresolved.

Reproduced with Effect but the bug is general: any npm package whose index.ts uses export * as Foo from "./Foo.js" exhibits the same silent-zero behavior under import { Foo } from "pkg".

What you expected

Either:

1. Preferred: traverse the re-export and pull ./X.js into the module graph the same way import * as X from "pkg/X" does.
2. At minimum: emit a hard error or loud warning ("namespace re-export X from pkg/index.ts not traversed; calls on X will return 0"). Today the user gets a silently-broken binary.

Minimal reproduction

mkdir nsre-zero && cd nsre-zero
cat > package.json <<'JSON'
{
  "name": "nsre-zero",
  "version": "0.0.0",
  "type": "module",
  "perry": { "compilePackages": ["effect"] }
}
JSON
bun add effect

// test_minimal.ts
import { Effect } from "effect";

const program = Effect.succeed(42);
const result = Effect.runSync(program);
console.log("result:", result);

Command:

perry compile test_minimal.ts -o /tmp/test_minimal
/tmp/test_minimal

Expected output: result: 42
Actual output: result: 0 — exit 0, no errors, no warnings about Effect being unresolved

Diagnostic output

perry compile -v test_minimal.ts ... surfaces the smoking gun:

Collecting modules...
  Compile package: effect
Found 3 module(s): 3 native, 0 JavaScript
Module init order (2 modules):
  [0] node_modules/effect/src/Function.ts
  [1] node_modules/effect/src/index.ts

Only 2 of Effect's 152 modules were collected. effect/src/Effect.ts (29,102 lines, the actual implementation) was never visited despite being explicitly named in the index.ts re-export. By contrast, import * as Effect from "effect/Effect" correctly pulls 152 modules (then OOMs on a separate Perry-side bug — filed as #309).

Relevant source

effect/src/index.ts line 229:

export * as Effect from "./Effect.js"

This is a standard ES2020 namespace re-export and is the recommended pattern for "deep stdlib" packages (Effect, lodash-fp, ramda, etc.) — Perry should support it for compilePackages resolution.

Environment

• Perry version: 0.5.399
• Host OS: macOS 26.4 (arm64, Apple Silicon)
• Target: native
• Installed via: from source
• Effect version: 3.21.2

Notes for triage

• Likely fix site: crates/perry/src/commands/compile/collect_modules.rs and / or crates/perry/src/commands/compile/resolve.rs (the v0.5.340 split). The import { Foo } from "pkg" code path needs to consult the resolved pkg's exports for Foo — and when Foo is itself a namespace re-export pointing at another file, recurse into that file's module graph.
• A scoped workaround that doesn't fix the silent-zero but stops the false success: when a user-side PropertyGet lowers to "unknown identifier X" AND X came from an import { X } from "pkg" binding, upgrade from "warn-and-lower-to-0" to a hard error. Today's "warn at lowering site, lower to 0" is the right default for genuinely-runtime-resolved globals (Intl, globalThis.foo) but completely wrong for an import that the resolver gave up on.

Why this matters

This is a silent-correctness bug — the binary produces wrong output and exits 0. Users with even modestly large dependency graphs will hit this without realizing it; the failure mode is "my Effect program prints all zeros" not "my Effect program won't compile." That is the worst possible failure mode for a compiler.