Fix up imports

Author: dwoz

relenv/build/darwin.py

@@ -6,7 +6,14 @@
 """
 from __future__ import annotations
 
+import glob
 import io
+import os
+import pathlib
+import shutil
+import tarfile
+import time
+import urllib.request
 from typing import IO, MutableMapping
 
 from ..common import DARWIN, MACOS_DEVELOPMENT_TARGET, arches
@@ -18,6 +25,7 @@
     finalize,
     get_dependency_version,
     runcmd,
+    update_sbom_checksums,
 )
 
 ARCHES = arches[DARWIN]
@@ -53,12 +61,6 @@ def update_expat(dirs: Dirs, env: MutableMapping[str, str]) -> None:
     Python ships with an older bundled expat. This function updates it
     to the latest version for security and bug fixes.
     """
-    import pathlib
-    import shutil
-    import glob
-    import urllib.request
-    import tarfile
-
     # Get version from JSON
     expat_info = get_dependency_version("expat", "darwin")
     if not expat_info:
@@ -97,16 +99,11 @@ def update_expat(dirs: Dirs, env: MutableMapping[str, str]) -> None:
 
     # Touch all updated files to ensure make rebuilds them
     # (The tarball may contain files with newer timestamps)
-    import time
-    import os
-
     now = time.time()
     for target_file in updated_files:
         os.utime(target_file, (now, now))
 
     # Update SBOM with correct checksums for updated expat files
-    from relenv.build.common import update_sbom_checksums
-
     files_to_update = {}
     for target_file in updated_files:
         # SBOM uses relative paths from Python source root

relenv/build/linux.py

@@ -6,11 +6,15 @@
 """
 from __future__ import annotations
 
+import glob
 import io
 import os
 import pathlib
 import shutil
+import tarfile
 import tempfile
+import time
+import urllib.request
 from typing import IO, MutableMapping
 
 from .common import (
@@ -22,6 +26,7 @@
     finalize,
     get_dependency_version,
     runcmd,
+    update_sbom_checksums,
 )
 from ..common import LINUX, Version, arches
 
@@ -368,13 +373,6 @@ def update_expat(dirs: Dirs, env: EnvMapping) -> None:
     Python ships with an older bundled expat. This function updates it
     to the latest version for security and bug fixes.
     """
-    from .common import get_dependency_version
-    import urllib.request
-    import tarfile
-    import glob
-    import pathlib
-    import shutil
-
     # Get version from JSON
     expat_info = get_dependency_version("expat", "linux")
     if not expat_info:
@@ -413,15 +411,11 @@ def update_expat(dirs: Dirs, env: EnvMapping) -> None:
 
     # Touch all updated files to ensure make rebuilds them
     # (The tarball may contain files with newer timestamps)
-    import time
-
     now = time.time()
     for target_file in updated_files:
         os.utime(target_file, (now, now))
 
     # Update SBOM with correct checksums for updated expat files
-    from relenv.build.common import update_sbom_checksums
-
     files_to_update = {}
     for target_file in updated_files:
         # SBOM uses relative paths from Python source root

relenv/build/windows.py

@@ -14,6 +14,7 @@
 import shutil
 import sys
 import tarfile
+import time
 from typing import IO, MutableMapping, Union
 
 from .common import (
@@ -28,6 +29,7 @@
     patch_file,
     runcmd,
     update_ensurepip,
+    update_sbom_checksums,
 )
 from ..common import WIN32, arches
 
@@ -145,6 +147,25 @@ def update_sqlite(dirs: Dirs, env: EnvMapping) -> None:
 def update_xz(dirs: Dirs, env: EnvMapping) -> None:
     """
     Update the XZ library.
+
+    COMPATIBILITY NOTE: We use config.h from XZ 5.4.7 for all XZ versions.
+    Starting with XZ 5.5.0, the project removed Visual Studio .vcxproj files
+    and switched to CMake. Python's build system (PCbuild/liblzma.vcxproj)
+    still expects MSBuild-compatible builds, so we maintain a compatibility
+    shim at relenv/_resources/xz/config.h.
+
+    When updating XZ versions, verify compatibility by checking:
+    1. Build completes without compiler errors
+    2. test_xz_lzma_functionality passes
+    3. No new HAVE_* defines required in src/liblzma source files
+    4. No removed HAVE_* defines that config.h references
+
+    If compatibility breaks, you have two options:
+    - Use CMake to generate new config.h for Windows (see discussion at
+      https://discuss.python.org/t/building-python-from-source-on-windows-using-a-custom-version-of-xz/74717)
+    - Update relenv/_resources/xz/config.h manually from newer XZ source
+
+    See also: relenv/_resources/xz/readme.md
     """
     # Try to get version from JSON
     # Note: Windows may use a different XZ version than Linux/Darwin due to MSBuild compatibility
@@ -237,16 +258,12 @@ def update_expat(dirs: Dirs, env: EnvMapping) -> None:
 
     # Touch all updated files to ensure MSBuild rebuilds them
     # (The original files may have newer timestamps)
-    import time
-
     now = time.time()
     for target_file in updated_files:
         os.utime(target_file, (now, now))
 
     # Update SBOM with correct checksums for updated expat files
     # Map SBOM file names to actual file paths
-    from relenv.build.common import update_sbom_checksums
-
     files_to_update = {}
     for target_file in updated_files:
         # SBOM uses relative paths from Python source root

tests/test_verify_build.py

@@ -2249,3 +2249,79 @@ def test_openssl_version(pyexec):
         f"OpenSSL version mismatch on {platform}: expected {expected_version}, "
         f"found {actual_version} (from {actual_version_str})"
     )
+
+
+def test_xz_lzma_functionality(pyexec):
+    """
+    Verify that the lzma module works correctly.
+
+    This is especially important for Windows builds which use a config.h
+    compatibility shim from XZ 5.4.7 to support newer XZ versions that
+    removed MSBuild support.
+
+    If this test fails, it indicates that the config.h in
+    relenv/_resources/xz/config.h is no longer compatible with the
+    current XZ version being used.
+
+    Works on all platforms: Linux, Darwin (macOS), and Windows.
+    """
+    # Test that lzma module loads and basic compression works
+    test_code = """
+import lzma
+import sys
+
+# Test basic compression/decompression
+test_data = b"Hello, World! " * 100
+compressed = lzma.compress(test_data)
+decompressed = lzma.decompress(compressed)
+
+if test_data != decompressed:
+    print("ERROR: Decompressed data does not match original", file=sys.stderr)
+    sys.exit(1)
+
+# Verify compression actually happened
+if len(compressed) >= len(test_data):
+    print("ERROR: Compression did not reduce size", file=sys.stderr)
+    sys.exit(2)
+
+# Test different formats (skip FORMAT_RAW as it requires explicit filters)
+for fmt in [lzma.FORMAT_XZ, lzma.FORMAT_ALONE]:
+    try:
+        data = lzma.compress(test_data, format=fmt)
+        result = lzma.decompress(data)
+        if result != test_data:
+            print(f"ERROR: Format {fmt} failed round-trip", file=sys.stderr)
+            sys.exit(3)
+    except Exception as e:
+        print(f"ERROR: Format {fmt} raised exception: {e}", file=sys.stderr)
+        sys.exit(4)
+
+# Test streaming compression/decompression
+import io
+output = io.BytesIO()
+with lzma.LZMAFile(output, "w") as f:
+    f.write(test_data)
+
+compressed_stream = output.getvalue()
+input_stream = io.BytesIO(compressed_stream)
+with lzma.LZMAFile(input_stream, "r") as f:
+    decompressed_stream = f.read()
+
+if decompressed_stream != test_data:
+    print("ERROR: Streaming compression/decompression failed", file=sys.stderr)
+    sys.exit(5)
+
+print("OK")
+"""
+
+    proc = subprocess.run(
+        [str(pyexec), "-c", test_code],
+        capture_output=True,
+        check=False,
+    )
+
+    assert proc.returncode == 0, (
+        f"LZMA functionality test failed (exit code {proc.returncode}): "
+        f"{proc.stderr.decode()}"
+    )
+    assert proc.stdout.decode().strip() == "OK"