feat: bun_script

internal/bun_script.bzl

@@ -0,0 +1,91 @@
+"""Rule for running package.json scripts with Bun."""
+
+
+def _shell_quote(value):
+    return "'" + value.replace("'", "'\"'\"'") + "'"
+
+
+def _bun_script_impl(ctx):
+    toolchain = ctx.toolchains["//bun:toolchain_type"]
+    bun_bin = toolchain.bun.bun_bin
+    package_json = ctx.file.package_json
+
+    launcher = ctx.actions.declare_file(ctx.label.name)
+    ctx.actions.write(
+        output = launcher,
+        is_executable = True,
+        content = """#!/usr/bin/env bash
+set -euo pipefail
+
+runfiles_dir="${{RUNFILES_DIR:-$0.runfiles}}"
+workspace_root="${{runfiles_dir}}/_main"
+bun_bin="${{runfiles_dir}}/_main/{bun_short_path}"
+package_json="${{runfiles_dir}}/_main/{package_json_short_path}"
+package_dir="$(dirname "${{package_json}}")"
+
+working_dir="{working_dir}"
+if [[ "${{working_dir}}" == "package" ]]; then
+    cd "${{package_dir}}"
+else
+    cd "${{workspace_root}}"
+fi
+
+exec "${{bun_bin}}" --bun run {script} "$@"
+""".format(
+            bun_short_path = bun_bin.short_path,
+            package_json_short_path = package_json.short_path,
+            working_dir = ctx.attr.working_dir,
+            script = _shell_quote(ctx.attr.script),
+        ),
+    )
+
+    transitive_files = []
+    if ctx.attr.node_modules:
+        transitive_files.append(ctx.attr.node_modules[DefaultInfo].files)
+
+    runfiles = ctx.runfiles(
+        files = [bun_bin, package_json] + ctx.files.data,
+        transitive_files = depset(transitive = transitive_files),
+    )
+
+    return [
+        DefaultInfo(
+            executable = launcher,
+            runfiles = runfiles,
+        ),
+    ]
+
+
+bun_script = rule(
+    implementation = _bun_script_impl,
+    doc = """Runs a named `package.json` script with Bun as an executable target.
+
+Use this rule to expose existing package scripts such as `dev`, `build`, or
+`check` via `bazel run` without adding wrapper shell scripts.
+""",
+    attrs = {
+        "script": attr.string(
+            mandatory = True,
+            doc = "Name of the `package.json` script to execute via `bun run <script>`.",
+        ),
+        "package_json": attr.label(
+            mandatory = True,
+            allow_single_file = True,
+            doc = "Label of the `package.json` file containing the named script.",
+        ),
+        "node_modules": attr.label(
+            doc = "Optional label providing Bun/npm package files in runfiles.",
+        ),
+        "data": attr.label_list(
+            allow_files = True,
+            doc = "Additional runtime files required by the script.",
+        ),
+        "working_dir": attr.string(
+            default = "package",
+            values = ["workspace", "package"],
+            doc = "Working directory at runtime: Bazel runfiles `workspace` root or the directory containing `package.json`.",
+        ),
+    },
+    executable = True,
+    toolchains = ["//bun:toolchain_type"],
+)