Fix the single file libraries being copied as source.

The code generates a temp file with the library version.
By mistake that was ALWAYS copied back to the mpy file for single file libraries.
The temporary files for the package libraries were also not deleted.

For windows compatibility, the temporary file must be copied (and therefore erased) outside of the with block. In this PR we only keep the temporary file open the time to write to it, and then do the rest.

Author: Neradoc

circuitpython_build_tools/build.py

@@ -258,50 +258,49 @@ def library(library_path, output_directory, package_folder_prefix,
             output_directory,
             filename.relative_to(library_path).with_suffix(new_extension)
         )
-        temp_filename = ""
         with tempfile.NamedTemporaryFile(delete=False) as temp_file:
             _munge_to_temp(full_path, temp_file, library_version)
-
-            if mpy_cross:
-                mpy_success = subprocess.call([
-                    mpy_cross,
-                    "-o", output_file,
-                    "-s", str(filename.relative_to(library_path)),
-                    temp_file.name
-                ])
-                if mpy_success != 0:
-                    raise RuntimeError("mpy-cross failed on", full_path)
             temp_filename = temp_file.name
-        shutil.copyfile(temp_filename, output_file)
+            # Windows: close the temp file before it can be read or copied by name
+        if mpy_cross:
+            mpy_success = subprocess.call([
+                mpy_cross,
+                "-o", output_file,
+                "-s", str(filename.relative_to(library_path)),
+                temp_filename
+            ])
+            if mpy_success != 0:
+                raise RuntimeError("mpy-cross failed on", full_path)
+        else:
+            shutil.copyfile(temp_filename, output_file)
         os.remove(temp_filename)
 
     for filename in package_files:
         full_path = os.path.join(library_path, filename)
-        temp_filename = ""
         output_file = ""
         with tempfile.NamedTemporaryFile(delete=False) as temp_file:
             _munge_to_temp(full_path, temp_file, library_version)
-            if not mpy_cross or os.stat(full_path).st_size == 0:
-                output_file = os.path.join(output_directory,
-                                           filename.relative_to(library_path))
-                temp_filename = temp_file.name
-            else:
-                output_file = os.path.join(
-                    output_directory,
-                    filename.relative_to(library_path).with_suffix(new_extension)
-                )
-
-                mpy_success = subprocess.call([
-                    mpy_cross,
-                    "-o", output_file,
-                    "-s", str(filename.relative_to(library_path)),
-                    temp_file.name
-                ])
-                if mpy_success != 0:
-                    raise RuntimeError("mpy-cross failed on", full_path)
-        if temp_filename and output_file:
+            temp_filename = temp_file.name
+            # Windows: close the temp file before it can be read or copied by name
+        if not mpy_cross or os.stat(full_path).st_size == 0:
+            output_file = os.path.join(output_directory,
+                                       filename.relative_to(library_path))
             shutil.copyfile(temp_filename, output_file)
-            os.remove(temp_filename)
+        else:
+            output_file = os.path.join(
+                output_directory,
+                filename.relative_to(library_path).with_suffix(new_extension)
+            )
+
+            mpy_success = subprocess.call([
+                mpy_cross,
+                "-o", output_file,
+                "-s", str(filename.relative_to(library_path)),
+                temp_filename
+            ])
+            if mpy_success != 0:
+                raise RuntimeError("mpy-cross failed on", full_path)
+        os.remove(temp_filename)
 
     requirements_files = lib_path.glob("requirements.txt*")
     requirements_files = [f for f in requirements_files if f.stat().st_size > 0]