From 12ddcb273a2bb85e5e7af2f11f9463b6e85dabe7 Mon Sep 17 00:00:00 2001
From: Eric <eric@dgren.dev>
Date: Wed, 4 Mar 2026 03:10:35 +0000
Subject: [PATCH] feat: add phase 3 bun_binary bootstrap and tests

---
 README.md                       |  6 ++++
 bun/defs.bzl                    |  2 ++
 internal/bun_binary.bzl         | 51 +++++++++++++++++++++++++++++++--
 tests/binary_test/BUILD.bazel   | 35 ++++++++++++++++++++++
 tests/binary_test/hello.js      |  1 +
 tests/binary_test/hello.ts      |  2 ++
 tests/binary_test/run_binary.sh | 11 +++++++
 7 files changed, 106 insertions(+), 2 deletions(-)
 create mode 100644 tests/binary_test/BUILD.bazel
 create mode 100644 tests/binary_test/hello.js
 create mode 100644 tests/binary_test/hello.ts
 create mode 100755 tests/binary_test/run_binary.sh

diff --git a/README.md b/README.md
index a07dae7..67d7abf 100644
--- a/README.md
+++ b/README.md
@@ -16,3 +16,9 @@ Phase 2 bootstrap is in place:
 - Repository-rule based `bun_install` (`/internal/bun_install.bzl`)
 - Public export via `bun/defs.bzl`
 - Focused install behavior tests (`//tests/install_test:all`)
+
+Phase 3 bootstrap is in place:
+
+- Executable `bun_binary` rule (`/internal/bun_binary.bzl`)
+- Public export via `bun/defs.bzl`
+- Focused JS/TS runnable tests (`//tests/binary_test:all`)
diff --git a/bun/defs.bzl b/bun/defs.bzl
index 220f084..48cd3f7 100644
--- a/bun/defs.bzl
+++ b/bun/defs.bzl
@@ -1,9 +1,11 @@
+load("//internal:bun_binary.bzl", "bun_binary")
 load("//internal:bun_install.bzl", "bun_install")
 load(":repositories.bzl", "bun_register_toolchains", "bun_repositories")
 load(":toolchain.bzl", "BunToolchainInfo", "bun_toolchain")
 
 __all__ = [
     "BunToolchainInfo",
+    "bun_binary",
     "bun_install",
     "bun_register_toolchains",
     "bun_repositories",
diff --git a/internal/bun_binary.bzl b/internal/bun_binary.bzl
index e9808f9..0e2caf8 100644
--- a/internal/bun_binary.bzl
+++ b/internal/bun_binary.bzl
@@ -1,2 +1,49 @@
-def bun_binary(**_kwargs):
-    fail("bun_binary is not implemented yet")
+"""Rule for running JS/TS scripts with Bun."""
+
+
+def _bun_binary_impl(ctx):
+    toolchain = ctx.toolchains["//bun:toolchain_type"]
+    bun_bin = toolchain.bun.bun_bin
+    entry_point = ctx.file.entry_point
+
+    launcher = ctx.actions.declare_file(ctx.label.name)
+    ctx.actions.write(
+        output = launcher,
+        is_executable = True,
+        content = """#!/usr/bin/env bash
+set -euo pipefail
+
+exec \"{}\" run \"{}\" \"$@\"
+""".format(bun_bin.path, entry_point.path),
+    )
+
+    transitive_files = []
+    if ctx.attr.node_modules:
+        transitive_files.append(ctx.attr.node_modules[DefaultInfo].files)
+
+    runfiles = ctx.runfiles(
+        files = [bun_bin, entry_point] + ctx.files.data,
+        transitive_files = depset(transitive = transitive_files),
+    )
+
+    return [
+        DefaultInfo(
+            executable = launcher,
+            runfiles = runfiles,
+        ),
+    ]
+
+
+bun_binary = rule(
+    implementation = _bun_binary_impl,
+    attrs = {
+        "entry_point": attr.label(
+            mandatory = True,
+            allow_single_file = [".js", ".ts", ".jsx", ".tsx", ".mjs", ".cjs"],
+        ),
+        "node_modules": attr.label(),
+        "data": attr.label_list(allow_files = True),
+    },
+    executable = True,
+    toolchains = ["//bun:toolchain_type"],
+)
diff --git a/tests/binary_test/BUILD.bazel b/tests/binary_test/BUILD.bazel
new file mode 100644
index 0000000..e4b43d6
--- /dev/null
+++ b/tests/binary_test/BUILD.bazel
@@ -0,0 +1,35 @@
+load("//bun:defs.bzl", "bun_binary")
+
+bun_binary(
+    name = "hello_js_bin",
+    entry_point = "hello.js",
+    data = ["hello.js"],
+)
+
+sh_test(
+    name = "bun_binary_js_test",
+    srcs = ["run_binary.sh"],
+    args = ["$(location :hello_js_bin)", "hello-js"],
+    data = [":hello_js_bin"],
+    target_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+)
+
+bun_binary(
+    name = "hello_ts_bin",
+    entry_point = "hello.ts",
+    data = ["hello.ts"],
+)
+
+sh_test(
+    name = "bun_binary_ts_test",
+    srcs = ["run_binary.sh"],
+    args = ["$(location :hello_ts_bin)", "hello-ts"],
+    data = [":hello_ts_bin"],
+    target_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+)
diff --git a/tests/binary_test/hello.js b/tests/binary_test/hello.js
new file mode 100644
index 0000000..8f2ee2f
--- /dev/null
+++ b/tests/binary_test/hello.js
@@ -0,0 +1 @@
+console.log("hello-js");
diff --git a/tests/binary_test/hello.ts b/tests/binary_test/hello.ts
new file mode 100644
index 0000000..5740a46
--- /dev/null
+++ b/tests/binary_test/hello.ts
@@ -0,0 +1,2 @@
+const message: string = "hello-ts";
+console.log(message);
diff --git a/tests/binary_test/run_binary.sh b/tests/binary_test/run_binary.sh
new file mode 100755
index 0000000..e8b8757
--- /dev/null
+++ b/tests/binary_test/run_binary.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+binary="$1"
+expected="$2"
+output="$(${binary})"
+
+if [[ "${output}" != "${expected}" ]]; then
+  echo "Unexpected output from ${binary}: ${output}" >&2
+  exit 1
+fi