Use --metadata=STDOUT to simplify pdal_execute_pipeline

kart/point_cloud/__init__.py

@@ -1,8 +1,5 @@
 import json
-from pathlib import Path
-import tempfile
 
-from kart import is_windows
 from kart import subprocess_util as subprocess
 
 
@@ -15,37 +12,13 @@ def pdal_execute_pipeline(pipeline, *, env_overrides=None):
     # NOTE: Kart itself doesn't currently use env_overrides, but don't remove it.
     # PDAL uses environment variables for various purposes, and this is helpful for `kart ext-run` scripts.
 
-    if is_windows:
-        # On windows we can't keep the metadata file open while pdal writes to it:
-        with tempfile.NamedTemporaryFile(delete=False) as f_metadata:
-            metadata_path = Path(f_metadata.name)
+    output = subprocess.check_output(
+        ["pdal", "pipeline", "--stdin", "--metadata=STDOUT"],
+        input=json.dumps(pipeline),
+        encoding="utf-8",
+        env_overrides=env_overrides,
+    )
 
-        subprocess.run(
-            ["pdal", "pipeline", "--stdin", f"--metadata={metadata_path}"],
-            check=True,
-            input=json.dumps(pipeline),
-            encoding="utf-8",
-            capture_output=True,
-            env_overrides=env_overrides,
-        )
+    metadata = json.loads(output)
 
-        with metadata_path.open(encoding="utf-8") as f:
-            metadata = json.load(f)
-
-        metadata_path.unlink()
-        return metadata["stages"]
-
-    else:
-        with tempfile.NamedTemporaryFile() as f_metadata:
-
-            subprocess.run(
-                ["pdal", "pipeline", "--stdin", f"--metadata={f_metadata.name}"],
-                check=True,
-                input=json.dumps(pipeline),
-                encoding="utf-8",
-                capture_output=True,
-                env_overrides=env_overrides,
-            )
-            f_metadata.seek(0)
-            metadata = json.load(f_metadata)
-            return metadata["stages"]
+    return metadata["stages"]