From d7cecae9bb05e285124477d9bf2bbc5396e0fe53 Mon Sep 17 00:00:00 2001
From: Gabriel Gerlero <gerlero@users.noreply.github.com>
Date: Sun, 29 Sep 2024 20:47:50 -0300
Subject: [PATCH] Fix file IO

---
 foamlib/_files/_files.py       | 19 +++++++++++++------
 foamlib/_files/_io.py          | 18 ++++++++++--------
 tests/test_files/test_files.py |  4 ++++
 3 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/foamlib/_files/_files.py b/foamlib/_files/_files.py
index db3afc2..45a9554 100644
--- a/foamlib/_files/_files.py
+++ b/foamlib/_files/_files.py
@@ -184,17 +184,24 @@ def __setitem__(
             elif not isinstance(keywords, tuple):
                 keywords = (keywords,)
 
-            if (
-                not self
-                and "FoamFile" not in self
-                and (not keywords or keywords[0] != "FoamFile")
-            ):
+            try:
+                write_header = (
+                    not self
+                    and "FoamFile" not in self
+                    and (not keywords or keywords[0] != "FoamFile")
+                )
+            except FileNotFoundError:
+                write_header = not keywords or keywords[0] != "FoamFile"
+
+            if write_header:
                 self["FoamFile"] = {}
                 self.version = 2.0
                 self.format = "ascii"
                 self.class_ = "dictionary"
                 self.location = f'"{self.path.parent.name}"'
-                self.object_ = self.path.name
+                self.object_ = (
+                    self.path.stem if self.path.suffix == ".gz" else self.path.name
+                )
 
             kind = Kind.DEFAULT
             if keywords == ("internalField",) or (
diff --git a/foamlib/_files/_io.py b/foamlib/_files/_io.py
index 1c898f0..bc8002f 100644
--- a/foamlib/_files/_io.py
+++ b/foamlib/_files/_io.py
@@ -49,19 +49,21 @@ def _read(self, *, missing_ok: bool = False) -> Tuple[bytes, Parsed]:
             try:
                 contents = self.path.read_bytes()
             except FileNotFoundError:
-                if missing_ok:
-                    contents = b""
-                else:
-                    raise
-
-            if self.path.suffix == ".gz":
-                contents = gzip.decompress(contents)
+                contents = None
+            else:
+                assert isinstance(contents, bytes)
+                if self.path.suffix == ".gz":
+                    contents = gzip.decompress(contents)
 
             if contents != self.__contents:
                 self.__contents = contents
                 self.__parsed = None
 
-        assert self.__contents is not None
+        if self.__contents is None:
+            if missing_ok:
+                return b"", Parsed(b"")
+            else:
+                raise FileNotFoundError(self.path)
 
         if self.__parsed is None:
             parsed = Parsed(self.__contents)
diff --git a/tests/test_files/test_files.py b/tests/test_files/test_files.py
index b4a4967..00839bc 100644
--- a/tests/test_files/test_files.py
+++ b/tests/test_files/test_files.py
@@ -19,6 +19,10 @@ def test_write_read(tmp_path: Path) -> None:
     with pytest.raises(FileNotFoundError):
         d["key"]
 
+    with d:
+        with pytest.raises(FileNotFoundError):
+            d["key"]
+
     d[None] = "touch"
     assert len(d) == 1
     assert d[None] == "touch"