Server(feat[source_file]): add source_file() wrapping tmux source-file

why: source-file is needed for loading configuration files programmatically,
useful for applying settings or initializing environments.
what:
- Add Server.source_file() with path and quiet (-q) parameters
- Quiet mode suppresses errors for missing files
- Add tests for sourcing a config and verifying option applied, and quiet mode

Author: tony

src/libtmux/server.py

@@ -718,6 +718,40 @@ def list_buffers(self) -> list[str]:
 
         return proc.stdout
 
+    def source_file(
+        self,
+        path: StrPath,
+        *,
+        quiet: bool | None = None,
+    ) -> None:
+        """Source a tmux configuration file via ``$ tmux source-file``.
+
+        Parameters
+        ----------
+        path : str or PathLike
+            Path to the configuration file.
+        quiet : bool, optional
+            Suppress errors for missing files (``-q`` flag).
+
+        Examples
+        --------
+        >>> import pathlib
+        >>> conf = pathlib.Path(request.config.rootdir) / '..' / 'tmp_src.conf'
+        >>> _ = conf.write_text('set -g @test_source yes')
+        >>> server.source_file(str(conf))
+        """
+        tmux_args: tuple[str, ...] = ()
+
+        if quiet:
+            tmux_args += ("-q",)
+
+        tmux_args += (str(pathlib.Path(path).expanduser()),)
+
+        proc = self.cmd("source-file", *tmux_args)
+
+        if proc.stderr:
+            raise exc.LibTmuxException(proc.stderr)
+
     def list_clients(self) -> list[str]:
         """List connected clients via ``$ tmux list-clients``.
 

tests/test_server.py

@@ -605,6 +605,28 @@ def test_list_buffers(server: Server) -> None:
     assert len(result) >= 2
 
 
+def test_source_file(server: Server, tmp_path: pathlib.Path) -> None:
+    """Test Server.source_file() sources a config file."""
+    server.new_session(session_name="source_test")
+
+    conf = tmp_path / "source_test.conf"
+    conf.write_text("set -g @source_test_opt yes\n")
+
+    server.source_file(conf)
+
+    # Verify the option was set
+    result = server.cmd("show-options", "-gv", "@source_test_opt")
+    assert result.stdout[0] == "yes"
+
+
+def test_source_file_quiet(server: Server) -> None:
+    """Test Server.source_file() with quiet flag ignores missing files."""
+    server.new_session(session_name="source_quiet")
+
+    # Non-existent file with quiet should not raise
+    server.source_file("/nonexistent/path.conf", quiet=True)
+
+
 def test_list_clients(server: Server) -> None:
     """Test Server.list_clients() returns list without error."""
     server.new_session(session_name="list_clients_test")