refactor: register_node_modules_linker just writes the manifest

This makes it easier to reuse in nodejs_binary

internal/linker/link_node_modules.bzl

@@ -34,14 +34,12 @@ def add_arg(args, arg):
     else:
         args.add(arg)
 
-def register_node_modules_linker(ctx, args, inputs, data = []):
-    """Helps an action to run node by setting up the node_modules linker as a pre-process
+def write_node_modules_manifest(ctx, extra_data = []):
+    """Writes a manifest file read by the linker, containing info about resolving runtime dependencies
 
     Args:
-      ctx: Bazel's starlark execution context, used to get attributes and actions
-      args: Arguments being passed to the program; a linker argument will be appended
-      inputs: inputs being passed to the program; a linker input will be appended
-      data: labels to search for npm packages that need to be linked (ctx.attr.deps and ctx.attr.data will always be searched)
+        ctx: starlark rule execution context
+        extra_data: labels to search for npm packages that need to be linked (ctx.attr.deps and ctx.attr.data will always be searched)
     """
 
     mappings = {
@@ -53,7 +51,7 @@ def register_node_modules_linker(ctx, args, inputs, data = []):
     node_modules_root = ""
 
     # Look through data/deps attributes to find...
-    for dep in data + getattr(ctx.attr, "data", []) + getattr(ctx.attr, "deps", []):
+    for dep in extra_data + getattr(ctx.attr, "data", []) + getattr(ctx.attr, "deps", []):
         # ...the root directory for the third-party node_modules; we'll symlink the local "node_modules" to it
         if NpmPackageInfo in dep:
             possible_root = "/".join([dep[NpmPackageInfo].workspace, "node_modules"])
@@ -80,8 +78,7 @@ def register_node_modules_linker(ctx, args, inputs, data = []):
         "workspace": ctx.workspace_name,
     }
     ctx.actions.write(modules_manifest, str(content))
-    add_arg(args, "--bazel_node_modules_manifest=%s" % modules_manifest.path)
-    inputs.append(modules_manifest)
+    return modules_manifest
 
 def get_module_mappings(label, attrs, vars, rule_kind, srcs = [], workspace_name = None):
     """Returns the module_mappings from the given attrs.

internal/linker/test/integration/rule.bzl

@@ -1,18 +1,17 @@
 "Minimal fixture for executing the linker's starlark code"
 
-load("@build_bazel_rules_nodejs//internal/linker:link_node_modules.bzl", "module_mappings_aspect", "register_node_modules_linker")
+load("@build_bazel_rules_nodejs//internal/linker:link_node_modules.bzl", "module_mappings_aspect", "write_node_modules_manifest")
 
 def _linked(ctx):
-    inputs = ctx.files.deps[:]
-    outputs = [ctx.outputs.out]
-    args = ctx.actions.args()
-    register_node_modules_linker(ctx, args, inputs)
-    args.add(ctx.outputs.out.path)
+    modules_manifest = write_node_modules_manifest(ctx)
     ctx.actions.run(
-        inputs = inputs,
-        outputs = outputs,
+        inputs = ctx.files.deps + [modules_manifest],
+        outputs = [ctx.outputs.out],
         executable = ctx.executable.program,
-        arguments = [args],
+        arguments = [
+            "--bazel_node_modules_manifest=%s" % modules_manifest.path,
+            ctx.outputs.out.path,
+        ],
     )
 
 linked = rule(_linked, attrs = {

internal/providers/node_runtime_deps_info.bzl

@@ -14,7 +14,7 @@
 
 """ Custom provider that mimics the Runfiles, but doesn't incur the expense of creating the runfiles symlink tree"""
 
-load("//internal/linker:link_node_modules.bzl", "add_arg", "register_node_modules_linker")
+load("//internal/linker:link_node_modules.bzl", "add_arg", "write_node_modules_manifest")
 
 NodeRuntimeDepsInfo = provider(
     doc = """Stores runtime dependencies of a nodejs_binary or nodejs_test
@@ -54,7 +54,9 @@ def run_node(ctx, inputs, arguments, executable, **kwargs):
         extra_inputs = exec_attr[NodeRuntimeDepsInfo].deps.to_list()
         link_data = exec_attr[NodeRuntimeDepsInfo].pkgs
 
-    register_node_modules_linker(ctx, arguments, inputs, link_data)
+    modules_manifest = write_node_modules_manifest(ctx, link_data)
+    add_arg(arguments, "--bazel_node_modules_manifest=%s" % modules_manifest.path)
+    inputs.append(modules_manifest)
 
     # By using the run_node helper, you suggest that your program
     # doesn't implicitly use runfiles to require() things