Fix build tests failing silently (#8295)

* Prevent build tests from failing silently

* Fix failing build tests

* CHANGELOG

Author: cknitt

CHANGELOG.md

@@ -38,6 +38,7 @@
 #### :house: Internal
 
 - Reanalyze server: redesign incremental fixpoint with delete-then-rederive strategy and predecessor tracking, improving speed on deletions. https://github.com/rescript-lang/rescript/pull/8276
+- Fix build tests failing silently. https://github.com/rescript-lang/rescript/pull/8295
 
 # 13.0.0-alpha.2
 

lib_dev/process.js

@@ -32,6 +32,7 @@ export const {
   execBin,
   rescript,
   execBuild,
+  execBuildOrThrow,
   execClean,
 } = setup();
 
@@ -196,6 +197,25 @@ export function setup(cwd = process.cwd()) {
       return exec(rescript_exe, ["build", ...args], options);
     },
 
+    /**
+     * Execute ReScript `build` command directly and throw on non-zero exit
+     * while preserving captured stdout/stderr for quiet successful tests.
+     *
+     * @param {string[]} [args]
+     * @param {ExecOptions} [options]
+     * @return {Promise<ExecResult>}
+     */
+    async execBuildOrThrow(args = [], options = {}) {
+      const out = await exec(rescript_exe, ["build", ...args], options);
+      if (out.status !== 0) {
+        const err = new Error("ReScript build failed");
+        err.stack = out.stdout + out.stderr;
+        Object.assign(err, { execResult: out });
+        throw err;
+      }
+      return out;
+    },
+
     /**
      * Execute ReScript `clean` command directly
      *

tests/build_tests/case3/input.js

@@ -5,10 +5,10 @@ import fs from "node:fs/promises";
 import path from "node:path";
 import { setup } from "#dev/process";
 
-const { execBuild, execClean } = setup(import.meta.dirname);
+const { execBuildOrThrow, execClean } = setup(import.meta.dirname);
 
 await execClean();
-await execBuild();
+await execBuildOrThrow();
 
 const o = await fs.readFile(path.join("src", "hello.res.js"), "ascii");
 assert.ok(/HelloGen\.f/.test(o));

tests/build_tests/custom_namespace/input.js

@@ -1,10 +1,10 @@
 import * as assert from "node:assert";
 import { setup } from "#dev/process";
 
-const { execClean, execBuild } = setup(import.meta.dirname);
+const { execClean, execBuildOrThrow } = setup(import.meta.dirname);
 
 await execClean();
-await execBuild();
+await execBuildOrThrow();
 
 const x = await import("./src/demo.res.js");
 assert.equal(x.v, 42);

tests/build_tests/devonly/input.js

@@ -2,6 +2,6 @@
 
 import { setup } from "#dev/process";
 
-const { execBuild } = setup(import.meta.dirname);
+const { execBuildOrThrow } = setup(import.meta.dirname);
 
-await execBuild();
+await execBuildOrThrow();

tests/build_tests/exports/input.js

@@ -2,7 +2,8 @@
 
 import { setup } from "#dev/process";
 
-const { execBuild, execClean } = setup(import.meta.dirname);
+const { execBuildOrThrow, execClean } = setup(import.meta.dirname);
 
-await execBuild();
+await execClean();
+await execBuildOrThrow();
 await execClean();

tests/build_tests/hyphen2/input.js

@@ -2,7 +2,7 @@
 
 import { setup } from "#dev/process";
 
-const { execBuild, execClean } = setup(import.meta.dirname);
+const { execBuildOrThrow, execClean } = setup(import.meta.dirname);
 
-await execBuild();
+await execBuildOrThrow();
 await execClean();

tests/build_tests/jsx_settings_inheritance/input.js

@@ -2,7 +2,7 @@
 
 import { setup } from "#dev/process";
 
-const { execBuild, execClean } = setup(import.meta.dirname);
+const { execBuildOrThrow, execClean } = setup(import.meta.dirname);
 
 await execClean();
-await execBuild();
+await execBuildOrThrow();

tests/build_tests/nested/input.js

@@ -5,9 +5,9 @@ import * as fs from "node:fs/promises";
 import * as path from "node:path";
 import { setup } from "#dev/process";
 
-const { execBuild, execClean } = setup(import.meta.dirname);
+const { execBuildOrThrow, execClean } = setup(import.meta.dirname);
 
-await execBuild();
+await execBuildOrThrow();
 
 const content = await fs.readFile(
   path.join(import.meta.dirname, "src", "demo.js"),

tests/build_tests/nnest/input.js

@@ -5,9 +5,9 @@ import * as fs from "node:fs/promises";
 import * as path from "node:path";
 import { setup } from "#dev/process";
 
-const { execBuild, execClean } = setup(import.meta.dirname);
+const { execBuildOrThrow, execClean } = setup(import.meta.dirname);
 
-await execBuild();
+await execBuildOrThrow();
 
 const content = await fs.readFile(
   path.join(import.meta.dirname, "src", "demo.js"),