otk: implement simple --preload

src/otk/command.py

@@ -143,6 +143,12 @@ def parser_create() -> argparse.ArgumentParser:
         default=None,
         help="Target to output, required if more than one target exists in an omnifest.",
     )
+    parser_compile.add_argument(
+        "-p",
+        "--preload",
+        default=None,
+        help="Preload the given otk file before processing the input",
+    )
 
     parser_validate = subparsers.add_parser("validate", help="Validate an omnifest.")
     parser_validate.add_argument(

src/otk/document.py

@@ -30,7 +30,11 @@ def __init__(self, path: pathlib.Path, target: str = "", *, warn_duplicated_defs
                 raise OTKError("only target osbuild supported right now")
             self._osbuild_ctx = OSBuildContext(self._ctx)
         state = State()
-        tree = process_include(self._ctx, state, path)
+        if not isinstance(path, list):
+            path = [path]
+        tree = {}
+        for p in path:
+            tree.update(process_include(self._ctx, state, p))
         # XXX: review this code, the idea is to find top-level keys that
         # have no targets but that of course only works if there are
         # no targets in the resolving. this means we are currently forced

test/test_preload.py

@@ -0,0 +1,36 @@
+import logging
+import os
+import textwrap
+
+import pytest
+
+from otk.command import run
+
+
+def test_otk_preload_works(tmp_path, caplog):
+    preload_otk = tmp_path / "preload.yaml"
+    preload_otk.write_text(textwrap.dedent("""
+    otk.target.osbuild:
+      otk.define:
+        user:
+          modifications:
+            language: nl_NL.UTF-8
+    """))
+
+    test_otk = tmp_path / "foo.yaml"
+    test_otk.write_text(textwrap.dedent("""
+    otk.version: 1
+    otk.target.osbuild:
+      otk.define:
+        default:
+          modifications:
+            language: en_US.UTF-8   
+        modifications:
+          otk.op.join:
+            values:
+              - ${default.modifications}
+              - ${user.modifications}
+    """))
+    result_otk = tmp_path / "output.yaml"
+    run(["compile", os.fspath(test_otk), "-o", result_otk.as_posix()])
+    assert "xx" == result_otk.read_text()