fix(build): lock around logging and archiving portions (#2262)

* fix: lock around logging and archiving portions

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* refactor: fewer locks

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

pyodide-build/pyodide_build/buildall.py

@@ -15,7 +15,7 @@ from pathlib import Path
 from queue import PriorityQueue, Queue
 from threading import Lock, Thread
 from time import perf_counter, sleep
-from typing import Any, Optional
+from typing import Any, ClassVar, Optional
 
 from . import common
 from .buildpkg import needs_rebuild
@@ -79,6 +79,9 @@ class StdLibPackage(BasePackage):
 
 @total_ordering
 class Package(BasePackage):
+    # If the CWD matters, hold this lock
+    cwd_lock: ClassVar[Lock] = Lock()
+
     def __init__(self, pkgdir: Path):
         self.pkgdir = pkgdir
 
@@ -120,6 +123,9 @@ class Package(BasePackage):
         return None
 
     def build(self, outputdir: Path, args) -> None:
+        with self.__class__.cwd_lock:
+            log_dir = Path(args.log_dir).resolve() if args.log_dir else None
+
         with open(self.pkgdir / "build.log.tmp", "w") as f:
             p = subprocess.run(
                 [
@@ -162,9 +168,10 @@ class Package(BasePackage):
 
         if rebuilt:
             shutil.move(self.pkgdir / "build.log.tmp", self.pkgdir / "build.log")
-            if args.log_dir and (self.pkgdir / "build.log").exists():
+            if log_dir and (self.pkgdir / "build.log").exists():
                 shutil.copy(
-                    self.pkgdir / "build.log", Path(args.log_dir) / f"{self.name}.log"
+                    self.pkgdir / "build.log",
+                    log_dir / f"{self.name}.log",
                 )
         else:
             (self.pkgdir / "build.log.tmp").unlink()
@@ -181,11 +188,12 @@ class Package(BasePackage):
         if self.library:
             return
         if self.shared_library:
-            file_path = shutil.make_archive(
-                f"{self.name}-{self.version}", "zip", self.pkgdir / "dist"
-            )
-            shutil.copy(file_path, outputdir)
-            Path(file_path).unlink()
+            with self.__class__.cwd_lock:
+                file_path = shutil.make_archive(
+                    f"{self.name}-{self.version}", "zip", self.pkgdir / "dist"
+                )
+                shutil.copy(file_path, outputdir)
+                Path(file_path).unlink()
             return
         shutil.copy(self.wheel_path(), outputdir)
         test_path = self.tests_path()
@@ -380,9 +388,8 @@ def build_from_graph(pkg_map: dict[str, BasePackage], outputdir: Path, args) ->
     built_queue: Queue = Queue()
     thread_lock = Lock()
     queue_idx = 1
-    package_set: dict[
-        str, None
-    ] = {}  # using dict keys for insertion order preservation
+    # Using dict keys for insertion order preservation
+    package_set: dict[str, None] = {}
 
     def builder(n):
         nonlocal queue_idx