fix: escape backslashes, quotes, and control chars in daemon TOML serialization

code_review_graph/daemon.py

@@ -164,22 +164,56 @@ def load_config(path: Path | None = None) -> DaemonConfig:
 # ---------------------------------------------------------------------------
 
 
+# TOML basic strings have named escapes for these; everything else in
+# the control range must use the \uXXXX form.
+_TOML_SHORT_ESCAPES = {
+    "\\": "\\\\",
+    '"': '\\"',
+    "\b": "\\b",
+    "\t": "\\t",
+    "\n": "\\n",
+    "\f": "\\f",
+    "\r": "\\r",
+}
+
+
+def _toml_str(value: object) -> str:
+    """Render *value* as a TOML basic string.
+
+    Backslashes and double quotes are escape characters in TOML basic
+    strings, so Windows paths like ``C:\\Users\\x`` must be escaped or
+    the file fails to parse on the next load. Control characters
+    (U+0000-U+001F, U+007F) are forbidden unescaped by the TOML spec,
+    so they are escaped too — ``tomllib`` rejects the file otherwise.
+    """
+    chars: list[str] = []
+    for ch in str(value):
+        esc = _TOML_SHORT_ESCAPES.get(ch)
+        if esc is not None:
+            chars.append(esc)
+        elif ord(ch) < 0x20 or ord(ch) == 0x7F:
+            chars.append(f"\\u{ord(ch):04X}")
+        else:
+            chars.append(ch)
+    return '"' + "".join(chars) + '"'
+
+
 def _serialize_toml(config: DaemonConfig) -> str:
     """Serialize a :class:`DaemonConfig` to TOML text.
 
     ``tomllib`` is read-only, so we build the TOML manually.
     """
     lines: list[str] = [
         "[daemon]",
-        f'session_name = "{config.session_name}"',
-        f'log_dir = "{config.log_dir}"',
+        f"session_name = {_toml_str(config.session_name)}",
+        f"log_dir = {_toml_str(config.log_dir)}",
         f"poll_interval = {config.poll_interval}",
     ]
     for repo in config.repos:
         lines.append("")
         lines.append("[[repos]]")
-        lines.append(f'path = "{repo.path}"')
-        lines.append(f'alias = "{repo.alias}"')
+        lines.append(f"path = {_toml_str(repo.path)}")
+        lines.append(f"alias = {_toml_str(repo.alias)}")
     lines.append("")  # trailing newline
     return "\n".join(lines)
 

tests/test_daemon.py

@@ -13,6 +13,7 @@
     DaemonConfig,
     WatchDaemon,
     WatchRepo,
+    _serialize_toml,
     add_repo_to_config,
     clear_pid,
     is_daemon_running,
@@ -41,18 +42,20 @@ def sample_config_file(tmp_path):
     (repo_b / ".git").mkdir()
 
     config = tmp_path / "watch.toml"
+    # as_posix() keeps hand-written TOML valid on Windows, where native
+    # backslash paths are invalid basic-string escapes.
     config.write_text(
         f"[daemon]\n"
         f'session_name = "test-session"\n'
-        f'log_dir = "{tmp_path / "logs"}"\n'
+        f'log_dir = "{(tmp_path / "logs").as_posix()}"\n'
         f"poll_interval = 5\n"
         f"\n"
         f"[[repos]]\n"
-        f'path = "{repo_a}"\n'
+        f'path = "{repo_a.as_posix()}"\n'
         f'alias = "alpha"\n'
         f"\n"
         f"[[repos]]\n"
-        f'path = "{repo_b}"\n'
+        f'path = "{repo_b.as_posix()}"\n'
         f'alias = "beta"\n',
         encoding="utf-8",
     )
@@ -97,7 +100,7 @@ def test_load_config_missing_alias(self, tmp_path):
 
         config_file = tmp_path / "watch.toml"
         config_file.write_text(
-            f'[[repos]]\npath = "{repo}"\n',
+            f'[[repos]]\npath = "{repo.as_posix()}"\n',
             encoding="utf-8",
         )
         cfg = load_config(config_file)
@@ -126,8 +129,8 @@ def test_load_config_duplicate_alias(self, tmp_path):
 
         config_file = tmp_path / "watch.toml"
         config_file.write_text(
-            f'[[repos]]\npath = "{repo_a}"\nalias = "dup"\n\n'
-            f'[[repos]]\npath = "{repo_b}"\nalias = "dup"\n',
+            f'[[repos]]\npath = "{repo_a.as_posix()}"\nalias = "dup"\n\n'
+            f'[[repos]]\npath = "{repo_b.as_posix()}"\nalias = "dup"\n',
             encoding="utf-8",
         )
         cfg = load_config(config_file)
@@ -141,7 +144,7 @@ def test_load_config_no_git_dir(self, tmp_path):
 
         config_file = tmp_path / "watch.toml"
         config_file.write_text(
-            f'[[repos]]\npath = "{bare}"\nalias = "bare"\n',
+            f'[[repos]]\npath = "{bare.as_posix()}"\nalias = "bare"\n',
             encoding="utf-8",
         )
         cfg = load_config(config_file)
@@ -170,6 +173,40 @@ def test_serialize_roundtrip(self, tmp_path):
         assert loaded.repos[0].alias == "rt"
         assert loaded.repos[0].path == str(repo.resolve())
 
+    def test_serialize_toml_escapes_backslashes_and_quotes(self):
+        """Windows paths and quotes must survive serialize -> parse (WinError on load otherwise)."""
+        from code_review_graph.daemon import tomllib
+
+        config = DaemonConfig(
+            session_name='quo"ted',
+            log_dir=Path(r"C:\Users\example\logs"),
+            poll_interval=2,
+            repos=[WatchRepo(path=r"C:\Users\example\repo", alias="win")],
+        )
+        parsed = tomllib.loads(_serialize_toml(config))
+        assert parsed["daemon"]["session_name"] == 'quo"ted'
+        assert parsed["daemon"]["log_dir"] == str(Path(r"C:\Users\example\logs"))
+        assert parsed["repos"][0]["path"] == r"C:\Users\example\repo"
+
+    def test_serialize_toml_escapes_control_characters(self):
+        """Newlines, tabs, and other control chars must survive serialize -> parse.
+
+        TOML forbids unescaped control characters in basic strings, so a
+        pathological alias or session name must not corrupt the config file.
+        """
+        from code_review_graph.daemon import tomllib
+
+        weird = "line1\nline2\ttabbed\x01ctrl\x7fdel"
+        config = DaemonConfig(
+            session_name=weird,
+            log_dir=Path("logs"),
+            poll_interval=2,
+            repos=[WatchRepo(path="repo", alias="a\rb")],
+        )
+        parsed = tomllib.loads(_serialize_toml(config))
+        assert parsed["daemon"]["session_name"] == weird
+        assert parsed["repos"][0]["alias"] == "a\rb"
+
     def test_add_repo_to_config(self, tmp_path):
         """add_repo_to_config adds a repo and saves."""
         repo = tmp_path / "new-repo"