Check TypeScript 7 compatibility in pnpm check

.changeset/typescript-7-compatibility-lane.md

@@ -0,0 +1,3 @@
+---
+
+---

CONTRIBUTING.md

@@ -76,6 +76,31 @@ understands imports, re-exports, and dynamic imports, and enforces:
 The checker has executable fixture tests and runs as part of `pnpm check`. Add
 new rules only with a failing fixture that demonstrates the boundary.
 
+## TypeScript compatibility
+
+The repository toolchain uses TypeScript 6. TypeDoc, tstyche, and the
+repository scripts load its JavaScript compiler API, so the root `typescript`
+dependency stays on 6.x.
+
+`pnpm check` also verifies the native TypeScript 7 compiler. The private
+`tooling/typescript-7` workspace package pins it in its own `node_modules`, so
+its `tsc` binary never replaces the TypeScript 6 `tsc` used by the root and the
+publishable packages:
+
+- `pnpm typecheck:ts7` type-checks every package project and
+  `tsconfig.tests.json` without emitting. Run it after `pnpm typecheck` or
+  `pnpm build`, because package references resolve to the TypeScript 6
+  declaration output.
+- `pnpm test:consumer` compiles the packed consumer fixture with TypeScript 6
+  and then with TypeScript 7. Set `TSGO_BIN` to an executable native compiler to
+  check another TypeScript 7 build.
+
+Type tests run only with TypeScript 6: tstyche 7.2 selects targets from
+TypeScript 5.4 up to, but not including, 7.0, because TypeScript 7 does not
+provide the in-process compiler API that tstyche uses. TypeScript 7 still
+compiles the public types through the package projects and the runtime tests,
+but type assertions are evaluated only with TypeScript 6.
+
 ## API reference data
 
 `pnpm docs:api` generates an Effect-compatible TypeDoc dataset under

package.json

@@ -12,6 +12,7 @@
     "check:architecture": "node --test scripts/check-architecture.test.mjs && node scripts/check-architecture.mjs packages/effect-machine && node scripts/check-devtools-architecture.mjs packages/devtools",
     "check:ci": "node --test scripts/ci-changes.test.mjs scripts/effect-compatibility.test.mjs scripts/invoke-autocomplete.test.mjs scripts/release-contract.test.mjs scripts/runtime-performance-compatibility.test.mjs scripts/runtime-performance-regression.test.mjs",
     "typecheck": "pnpm --recursive --filter \"./packages/**\" run check && tsc -p tsconfig.tests.json",
+    "typecheck:ts7": "pnpm --dir tooling/typescript-7 run typecheck",
     "perf:types": "pnpm build && node scripts/type-performance.mjs",
     "perf:runtime": "pnpm build && node --expose-gc scripts/runtime-performance.mjs",
     "format": "dprint fmt",
@@ -28,7 +29,7 @@
     "react:pack-check": "node scripts/react-pack-check.mjs",
     "devtools:pack-check": "node scripts/devtools-pack-check.mjs",
     "oxlint-plugin:pack-check": "node scripts/oxlint-plugin-pack-check.mjs",
-    "check": "pnpm format:check && pnpm check:architecture && pnpm check:ci && pnpm docs:api:check && pnpm docs:site:check && pnpm typecheck && pnpm build && pnpm test && pnpm test:types && pnpm test:consumer && pnpm pack:check && pnpm react:pack-check && pnpm devtools:pack-check && pnpm oxlint-plugin:pack-check",
+    "check": "pnpm format:check && pnpm check:architecture && pnpm check:ci && pnpm docs:api:check && pnpm docs:site:check && pnpm typecheck && pnpm typecheck:ts7 && pnpm build && pnpm test && pnpm test:types && pnpm test:consumer && pnpm pack:check && pnpm react:pack-check && pnpm devtools:pack-check && pnpm oxlint-plugin:pack-check",
     "changeset": "changeset",
     "version-packages": "changeset version && dprint fmt",
     "release": "pnpm build && changeset publish"

packages/effect-machine/test/machine/Machine.test.ts

@@ -33,7 +33,7 @@ const sendAndWaitForSnapshot = <State, Event, Error, Output>(
 const assertStateSnapshot = <Path extends string, Value>(
   actual:
     | Machine.Machine.AtomicSnapshot<Path, Value>
-    | Machine.Machine.CompoundSnapshot<"", undefined, Machine.Machine.AtomicSnapshot<Path, Value>>,
+    | Machine.Machine.CompoundSnapshot<"", undefined, NoInfer<Machine.Machine.AtomicSnapshot<Path, Value>>>,
   path: Path,
   value: Value
 ) => {
@@ -47,7 +47,7 @@ const assertStateSnapshot = <Path extends string, Value>(
 const assertCompoundStateSnapshot = <Path extends string, Value, Child>(
   actual:
     | Machine.Machine.CompoundSnapshot<Path, Value, Child>
-    | Machine.Machine.CompoundSnapshot<"", undefined, Machine.Machine.CompoundSnapshot<Path, Value, Child>>,
+    | Machine.Machine.CompoundSnapshot<"", undefined, NoInfer<Machine.Machine.CompoundSnapshot<Path, Value, Child>>>,
   path: Path,
   value: Value,
   state: Child
@@ -63,7 +63,7 @@ const assertCompoundStateSnapshot = <Path extends string, Value, Child>(
 const assertParallelStateSnapshot = <Path extends string, Value, States>(
   actual:
     | Machine.Machine.ParallelSnapshot<Path, Value, States>
-    | Machine.Machine.CompoundSnapshot<"", undefined, Machine.Machine.ParallelSnapshot<Path, Value, States>>,
+    | Machine.Machine.CompoundSnapshot<"", undefined, NoInfer<Machine.Machine.ParallelSnapshot<Path, Value, States>>>,
   path: Path,
   value: Value,
   states: States

pnpm-workspace.yaml

@@ -1,5 +1,6 @@
 packages:
   - "packages/*"
+  - "tooling/*"
 
 overrides:
   effect: 4.0.0

scripts/test-consumer.mjs

@@ -51,12 +51,26 @@ try {
     [join(repositoryRoot, "node_modules", "typescript", "bin", "tsc"), "-p", join(consumer, "tsconfig.json")],
     { cwd: consumer }
   )
+  // The consumer must also compile with the native TypeScript 7 compiler pinned
+  // by tooling/typescript-7. TSGO_BIN selects another native compiler binary.
   if (process.env.TSGO_BIN !== undefined) {
     run(process.env.TSGO_BIN, ["-p", join(consumer, "tsconfig.json")], { cwd: consumer })
+  } else {
+    run(
+      process.execPath,
+      [
+        join(repositoryRoot, "tooling", "typescript-7", "node_modules", "typescript", "bin", "tsc"),
+        "-p",
+        join(consumer, "tsconfig.json")
+      ],
+      { cwd: consumer }
+    )
   }
   run(process.execPath, [join(consumer, "runtime.mjs")], { cwd: consumer })
 
-  console.log("packed root, reactivity, cluster, and testing entrypoints passed strict consumer validation")
+  console.log(
+    "packed root, reactivity, cluster, and testing entrypoints passed strict consumer validation with TypeScript 6 and 7"
+  )
 } finally {
   await rm(destination, { recursive: true, force: true })
 }

tooling/typescript-7/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "@typeonce/effect-machine-typescript-7",
+  "private": true,
+  "type": "module",
+  "description": "Pins the native TypeScript 7 compiler for the compatibility lane without replacing the TypeScript 6 toolchain.",
+  "scripts": {
+    "typecheck": "tsc -p ../../packages/effect-machine/tsconfig.json --noEmit && tsc -p ../../packages/effect-machine-react/tsconfig.json --noEmit && tsc -p ../../packages/oxlint-plugin/tsconfig.json --noEmit && tsc -p ../../packages/devtools/tsconfig.json && tsc -p ../../tsconfig.tests.json"
+  },
+  "devDependencies": {
+    "typescript": "7.0.2"
+  }
+}