diff --git a/labgrid/config/managers.bzl b/labgrid/config/managers.bzl
index df1bb66e8558868615e28c1336dd44575c60cbc9..beeaa821084c6b4eccaf8e523fb5a2365bbf7627 100644
--- a/labgrid/config/managers.bzl
+++ b/labgrid/config/managers.bzl
@@ -15,7 +15,7 @@ managers = rule(
     doc = DOC,
     attrs = ATTRS,
     implementation = implementation,
-    provides = [DefaultInfo, PyInfo],
+    provides = [PyInfo],
     toolchains = ["//labgrid/toolchain/config:type"],
     cfg = _cfg,
 )
diff --git a/labgrid/config/rule.bzl b/labgrid/config/rule.bzl
index 3751ead02327b86b8679dc230166496acc736dc3..35d8aea9541dfd1133090907e868ddd6865f1e6f 100644
--- a/labgrid/config/rule.bzl
+++ b/labgrid/config/rule.bzl
@@ -99,32 +99,18 @@ def _runfile(value, separator = "~"):
     return value
 
 def _merge_py_info(targets):
-    transitive_sources = []
-    imports = []
-    for target in targets:
-        p = target[PyInfo]
-        transitive_sources.extend(p.transitive_sources.to_list() if p.transitive_sources else [])
-        imports.extend(p.imports.to_list() if p.imports else [])
     return PyInfo(
-        transitive_sources = depset(transitive_sources),
-        imports = depset(imports),
+        transitive_sources = depset(transitive = [t[PyInfo].transitive_sources for t in targets]),
+        imports = depset(transitive = [t[PyInfo].imports for t in targets]),
     )
 
-def _merge_default_info(targets):
-    files = []
-    data_runfiles = []
-    default_runfiles = []
-    for target in targets:
-        d = target[DefaultInfo]
-        files.extend(d.files.to_list() if d.files else [])
-        if d.data_runfiles:
-            data_runfiles.append(d.data_runfiles)
-        if d.default_runfiles:
-            default_runfiles.append(d.default_runfiles)
+def _merge_default_info(ctx, targets):
+    files = depset(transitive = [t.files for t in targets])
+    runfiles = ctx.runfiles()
+    runfiles = runfiles.merge_all([t.default_runfiles for t in targets])
     return DefaultInfo(
-        files = depset(files),
-        data_runfiles = data_runfiles[0].merge_all(data_runfiles) if data_runfiles else None,
-        default_runfiles = default_runfiles[0].merge_all(default_runfiles) if default_runfiles else None,
+        files = files,
+        runfiles = runfiles,
     )
 
 def implementation(ctx):
@@ -133,10 +119,10 @@ def implementation(ctx):
     default = DefaultInfo(files = depset([ctx.file.src]))
     toolchain = platform_common.ToolchainInfo(
         src = ctx.file.src,
-        deps = [_merge_default_info(ctx.attr.deps), _merge_py_info(ctx.attr.deps)],
+        deps = [_merge_default_info(ctx, ctx.attr.deps), _merge_py_info(ctx.attr.deps)],
         env = env,
         data = depset(transitive = [d.files for d in data]),
-        managers = [_merge_default_info(ctx.attr.managers), _merge_py_info(ctx.attr.managers)],
+        managers = [_merge_default_info(ctx, ctx.attr.managers), _merge_py_info(ctx.attr.managers)],
     )
 
     return [default, toolchain]
diff --git a/labgrid/executor/args.bzl b/labgrid/executor/args.bzl
index 138aad82e8e1b618b03d715fbd3bc1529e73eb29..e09419c6459724a5ac4450e6b39f402c10e2a337 100644
--- a/labgrid/executor/args.bzl
+++ b/labgrid/executor/args.bzl
@@ -5,8 +5,7 @@ visibility("//labgrid/executor/...")
 DOC = "Creates an args file to be passed to `//labgrid/executor`"
 
 ATTRS = {
-    "_manager": attr.label_list(
-        allow_files = True,
+    "_managers": attr.label_list(
         doc = "The manager to use",
         default = ["//labgrid/config:managers"],
         cfg = "exec",
@@ -28,7 +27,7 @@ def implementation(ctx):
     output = ctx.actions.declare_file("executor-args.txt")
 
     lines = []
-    for m in ctx.files._manager:
+    for m in ctx.files._managers:
         lines.extend(["--manager", "{}:{}".format(_import_path(m.short_path), "manager")])
     for name, value in ctx.attr._env[EnvironmentInfo].environment.items():
         lines.extend(["--env", name, value])
diff --git a/labgrid/executor/executor.py b/labgrid/executor/executor.py
index b593cf604153819051a8aedd385f6092416aed52..fe189732904cb0f775c892a6259e37d431d97d72 100644
--- a/labgrid/executor/executor.py
+++ b/labgrid/executor/executor.py
@@ -19,7 +19,10 @@ from bazel.labgrid.executor.manager import Data, Manager
 
 
 def load(value: str) -> Manager:
-    name, _, attr = value.partition(":")
+    name, found, attr = value.partition(":")
+    if not found:
+        raise ArgumentTypeError(f"Must be of the form `<module>:<attr>`: {value}")
+
     module = import_module(name)
 
     try:
@@ -47,6 +50,8 @@ def arguments(prsr: ArgumentParser) -> None:
         help="A manager to load from a Python module, of the form `module.to.load:Manager`.",
         action="append",
         type=load,
+        default=[],
+        dest="managers",
     )
     prsr.add_argument(
         "--env",
@@ -78,9 +83,8 @@ def main(exe: Path, *args: str) -> int:
 
     data = Data(env={})
     with ExitStack() as stack:
-        if parsed.manager:
-            for manager in parsed.manager:
-                data = stack.enter_context(manager(data))
+        for manager in parsed.managers:
+            data = stack.enter_context(manager(data))
         env = {k: resolve_runfile(v) for k, v in parsed.env}
         env |= {k: v for k, v in data.env.items() if k != "RUNFILES_DIR"}
         try: