compile: separate project directory and file path in compile_file()

mpy-cross saves the file path as part of the binary file. To keep things
small and not leak host computer details, we want to only include the
portion of the path that is relative to the project directory.

Previously, this could only be done by changing the current working
directory to the project directory before calling compile_file(). Now,
that is no longer necessary and the project directory is passed as a
separate argument.

This fixes not being able to compile files piped from stdin when using
the cli tool.

Author: dlech

CHANGELOG.md

@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- Fix crash when running `pybricksdev run ble -` (bug introduced in alpha.49).
+
 ## [1.0.0-alpha.52] - 2024-11-29
 
 ### Added

pybricksdev/cli/flash.py

@@ -5,6 +5,7 @@
 import hashlib
 import json
 import logging
+import os
 import struct
 import sys
 import zipfile
@@ -117,7 +118,9 @@ async def download_and_run(client: BleakClient, script: str, abi: int) -> None:
         # file has to be closed so mpy-cross can open it
         temp.file.close()
 
-        mpy = await compile_file(temp.name, abi)
+        mpy = await compile_file(
+            os.path.dirname(temp.name), os.path.basename(temp.name), abi
+        )
 
     recv_queue = asyncio.Queue()
 

pybricksdev/compile.py

@@ -29,12 +29,17 @@ def make_build_dir():
         raise FileExistsError("A file named build already exists.")
 
 
-async def compile_file(path: str, abi: int, compile_args: Optional[List[str]] = None):
+async def compile_file(
+    proj_dir: str, proj_path: str, abi: int, compile_args: Optional[List[str]] = None
+):
     """Compiles a Python file with ``mpy-cross``.
 
     Arguments:
-        path:
-            Path to script that is to be compiled.
+        proj_dir:
+            Path to project containing the script to be compiled
+        proj_path:
+            Path to script that is to be compiled relative to proj_dir. This is
+            the portion of the name that is passed to ``mpy-cross``.
         abi:
             Expected MPY ABI version.
         compile_args:
@@ -50,22 +55,22 @@ async def compile_file(path: str, abi: int, compile_args: Optional[List[str]] =
     """
 
     # Get version info
-    with open(path, "r") as f:
+    with open(os.path.join(proj_dir, proj_path), "r") as f:
         loop = asyncio.get_running_loop()
         script = f.read()
 
         if abi == 5:
             proc, mpy = await loop.run_in_executor(
                 None,
                 lambda: mpy_cross_v5.mpy_cross_compile(
-                    path, script, no_unicode=True, extra_args=compile_args
+                    proj_path, script, no_unicode=True, extra_args=compile_args
                 ),
             )
         elif abi == 6:
             proc, mpy = await loop.run_in_executor(
                 None,
                 lambda: mpy_cross_v6.mpy_cross_compile(
-                    path, script, extra_args=compile_args
+                    proj_path, script, extra_args=compile_args
                 ),
             )
         else:
@@ -114,7 +119,8 @@ async def compile_multi_file(path: str, abi: Union[int, Tuple[int, int]]):
     """
 
     # compile files using Python to find imports contained within the same directory as path
-    search_path = [os.path.dirname(path)]
+    proj_path = os.path.dirname(path)
+    search_path = [proj_path]
     finder = ModuleFinder(search_path)
 
     try:
@@ -136,9 +142,9 @@ async def compile_multi_file(path: str, abi: Union[int, Tuple[int, int]]):
         if not module.__file__:
             continue
 
-        relative_file = os.path.relpath(module.__file__, os.path.dirname(path))
-
-        mpy = await compile_file(relative_file, abi_major)
+        mpy = await compile_file(
+            proj_path, os.path.relpath(module.__file__, proj_path), abi_major
+        )
 
         parts.append(len(mpy).to_bytes(4, "little"))
         parts.append(name.encode() + b"\x00")

pybricksdev/connections/pybricks.py

@@ -582,7 +582,9 @@ async def _legacy_run(self, py_path: str, wait: bool) -> None:
         Version of :meth:`run` for compatibility with older firmware ()
         """
         # Compile the script to mpy format
-        mpy = await compile_file(py_path, self._mpy_abi_version)
+        mpy = await compile_file(
+            os.path.dirname(py_path), os.path.basename(py_path), self._mpy_abi_version
+        )
 
         try:
             self._downloading_via_nus = True

pybricksdev/firmware.py

@@ -133,9 +133,11 @@ async def _create_firmware_v1(
 
     if "main.py" in archive.namelist():
         main_py = io.TextIOWrapper(archive.open("main.py"))
+        main_py_path = save_script(main_py.read())
 
         mpy = await compile_file(
-            save_script(main_py.read()),
+            os.path.dirname(main_py_path),
+            os.path.basename(main_py_path),
             metadata["mpy-abi-version"],
             metadata["mpy-cross-options"],
         )

tests/test_compile.py

@@ -19,7 +19,9 @@ async def test_compile_file(abi: int):
             f.write("print('test')")
             f.close()
 
-            mpy = await compile_file(f.name, abi=abi)
+            mpy = await compile_file(
+                os.path.dirname(f.name), os.path.basename(f.name), abi=abi
+            )
 
             magic, abi_ver, flags, int_bits = struct.unpack_from("<BBBB", mpy)