From 9868933b27de58befbce8a9b800e4dce918b5e4f Mon Sep 17 00:00:00 2001
From: Eric <eric@dgren.dev>
Date: Wed, 4 Mar 2026 07:31:19 +0000
Subject: [PATCH] feat: add phase 6 js_library and ts_library bootstrap

---
 README.md                           |  6 +++++
 bun/defs.bzl                        |  3 +++
 internal/bun_bundle.bzl             |  8 ++++++
 internal/bun_test.bzl               |  8 ++++++
 internal/js_library.bzl             | 40 ++++++++++++++++++++++++++++
 tests/library_test/BUILD.bazel      | 41 +++++++++++++++++++++++++++++
 tests/library_test/app.test.ts      |  6 +++++
 tests/library_test/app.ts           |  3 +++
 tests/library_test/helper.ts        |  3 +++
 tests/library_test/verify_bundle.sh |  9 +++++++
 10 files changed, 127 insertions(+)
 create mode 100644 internal/js_library.bzl
 create mode 100644 tests/library_test/BUILD.bazel
 create mode 100644 tests/library_test/app.test.ts
 create mode 100644 tests/library_test/app.ts
 create mode 100644 tests/library_test/helper.ts
 create mode 100755 tests/library_test/verify_bundle.sh

diff --git a/README.md b/README.md
index 4b178e5..43598c1 100644
--- a/README.md
+++ b/README.md
@@ -34,3 +34,9 @@ Phase 5 bootstrap is in place:
 - Bundle rule `bun_bundle` (`/internal/bun_bundle.bzl`)
 - Public export via `bun/defs.bzl`
 - Focused output/minify tests (`//tests/bundle_test:all`)
+
+Phase 6 bootstrap is in place:
+
+- Source grouping rules `js_library` / `ts_library` (`/internal/js_library.bzl`)
+- Transitive `deps` propagation wired into `bun_bundle` and `bun_test`
+- Focused dependency-propagation tests (`//tests/library_test:all`)
diff --git a/bun/defs.bzl b/bun/defs.bzl
index 85fd304..91bfc90 100644
--- a/bun/defs.bzl
+++ b/bun/defs.bzl
@@ -1,6 +1,7 @@
 load("//internal:bun_binary.bzl", _bun_binary = "bun_binary")
 load("//internal:bun_bundle.bzl", _bun_bundle = "bun_bundle")
 load("//internal:bun_test.bzl", _bun_test = "bun_test")
+load("//internal:js_library.bzl", _js_library = "js_library", _ts_library = "ts_library")
 load(":toolchain.bzl", _BunToolchainInfo = "BunToolchainInfo", _bun_toolchain = "bun_toolchain")
 
 visibility("public")
@@ -8,5 +9,7 @@ visibility("public")
 bun_binary = _bun_binary
 bun_bundle = _bun_bundle
 bun_test = _bun_test
+js_library = _js_library
+ts_library = _ts_library
 BunToolchainInfo = _BunToolchainInfo
 bun_toolchain = _bun_toolchain
diff --git a/internal/bun_bundle.bzl b/internal/bun_bundle.bzl
index 13af4bc..56b6aee 100644
--- a/internal/bun_bundle.bzl
+++ b/internal/bun_bundle.bzl
@@ -1,5 +1,7 @@
 """Rule for bundling JS/TS sources with Bun."""
 
+load("//internal:js_library.bzl", "BunSourcesInfo")
+
 
 def _output_name(target_name, entry):
     stem = entry.basename.rsplit(".", 1)[0]
@@ -13,6 +15,11 @@ def _bun_bundle_impl(ctx):
     transitive_inputs = []
     if ctx.attr.node_modules:
         transitive_inputs.append(ctx.attr.node_modules[DefaultInfo].files)
+    for dep in ctx.attr.deps:
+        if BunSourcesInfo in dep:
+            transitive_inputs.append(dep[BunSourcesInfo].transitive_sources)
+        else:
+            transitive_inputs.append(dep[DefaultInfo].files)
 
     outputs = []
     for entry in ctx.files.entry_points:
@@ -59,6 +66,7 @@ bun_bundle = rule(
             allow_files = [".js", ".ts", ".jsx", ".tsx", ".mjs", ".cjs"],
         ),
         "node_modules": attr.label(),
+        "deps": attr.label_list(),
         "data": attr.label_list(allow_files = True),
         "target": attr.string(
             default = "browser",
diff --git a/internal/bun_test.bzl b/internal/bun_test.bzl
index 63f2c4d..5e46a71 100644
--- a/internal/bun_test.bzl
+++ b/internal/bun_test.bzl
@@ -1,5 +1,7 @@
 """Rule for running test suites with Bun."""
 
+load("//internal:js_library.bzl", "BunSourcesInfo")
+
 
 def _shell_quote(value):
     return "'" + value.replace("'", "'\"'\"'") + "'"
@@ -34,6 +36,11 @@ exec "{bun_bin}" test {src_args} "${{extra_args[@]}}" "$@"
     transitive_files = []
     if ctx.attr.node_modules:
         transitive_files.append(ctx.attr.node_modules[DefaultInfo].files)
+    for dep in ctx.attr.deps:
+        if BunSourcesInfo in dep:
+            transitive_files.append(dep[BunSourcesInfo].transitive_sources)
+        else:
+            transitive_files.append(dep[DefaultInfo].files)
 
     runfiles = ctx.runfiles(
         files = [bun_bin] + ctx.files.srcs + ctx.files.data,
@@ -56,6 +63,7 @@ bun_test = rule(
             allow_files = [".js", ".ts", ".jsx", ".tsx", ".mjs", ".cjs"],
         ),
         "node_modules": attr.label(),
+        "deps": attr.label_list(),
         "data": attr.label_list(allow_files = True),
     },
     test = True,
diff --git a/internal/js_library.bzl b/internal/js_library.bzl
new file mode 100644
index 0000000..4247824
--- /dev/null
+++ b/internal/js_library.bzl
@@ -0,0 +1,40 @@
+"""Lightweight JS/TS source grouping rules."""
+
+BunSourcesInfo = provider(fields = ["transitive_sources"])
+
+
+def _bun_library_impl(ctx):
+    transitive_sources = [
+        dep[BunSourcesInfo].transitive_sources
+        for dep in ctx.attr.deps
+        if BunSourcesInfo in dep
+    ]
+    all_sources = depset(
+        direct = ctx.files.srcs,
+        transitive = transitive_sources,
+    )
+    return [
+        BunSourcesInfo(transitive_sources = all_sources),
+        DefaultInfo(files = all_sources),
+    ]
+
+
+js_library = rule(
+    implementation = _bun_library_impl,
+    attrs = {
+        "srcs": attr.label_list(
+            allow_files = [".js", ".jsx", ".mjs", ".cjs"],
+        ),
+        "deps": attr.label_list(),
+    },
+)
+
+ts_library = rule(
+    implementation = _bun_library_impl,
+    attrs = {
+        "srcs": attr.label_list(
+            allow_files = [".ts", ".tsx"],
+        ),
+        "deps": attr.label_list(),
+    },
+)
diff --git a/tests/library_test/BUILD.bazel b/tests/library_test/BUILD.bazel
new file mode 100644
index 0000000..2cfacac
--- /dev/null
+++ b/tests/library_test/BUILD.bazel
@@ -0,0 +1,41 @@
+load("//bun:defs.bzl", "bun_bundle", "bun_test", "ts_library")
+
+ts_library(
+    name = "helper_lib",
+    srcs = ["helper.ts"],
+    target_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+)
+
+bun_bundle(
+    name = "bundle_with_deps",
+    entry_points = ["app.ts"],
+    deps = [":helper_lib"],
+    target_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+)
+
+sh_test(
+    name = "bundle_dep_propagation_test",
+    srcs = ["verify_bundle.sh"],
+    args = ["$(location :bundle_with_deps)"],
+    data = [":bundle_with_deps"],
+    target_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+)
+
+bun_test(
+    name = "test_with_deps",
+    srcs = ["app.test.ts"],
+    deps = [":helper_lib"],
+    target_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+)
diff --git a/tests/library_test/app.test.ts b/tests/library_test/app.test.ts
new file mode 100644
index 0000000..46535b9
--- /dev/null
+++ b/tests/library_test/app.test.ts
@@ -0,0 +1,6 @@
+import { expect, test } from "bun:test";
+import { greeting } from "./helper";
+
+test("uses helper from ts_library dep", () => {
+  expect(greeting("test")).toBe("hello-test");
+});
diff --git a/tests/library_test/app.ts b/tests/library_test/app.ts
new file mode 100644
index 0000000..d248746
--- /dev/null
+++ b/tests/library_test/app.ts
@@ -0,0 +1,3 @@
+import { greeting } from "./helper";
+
+console.log(greeting("bundle"));
diff --git a/tests/library_test/helper.ts b/tests/library_test/helper.ts
new file mode 100644
index 0000000..cdf8ab7
--- /dev/null
+++ b/tests/library_test/helper.ts
@@ -0,0 +1,3 @@
+export function greeting(name: string): string {
+  return `hello-${name}`;
+}
diff --git a/tests/library_test/verify_bundle.sh b/tests/library_test/verify_bundle.sh
new file mode 100755
index 0000000..006fd97
--- /dev/null
+++ b/tests/library_test/verify_bundle.sh
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+bundle="$1"
+
+if [[ ! -s "${bundle}" ]]; then
+  echo "Expected bundled output to exist and be non-empty: ${bundle}" >&2
+  exit 1
+fi