From 3030fb9e30d7724c05ea82e1ef6a52e35de45b19 Mon Sep 17 00:00:00 2001
From: JB Lovland <jlov@equinor.com>
Date: Mon, 4 Dec 2023 14:25:30 +0100
Subject: [PATCH] CLN: Add types grid-import

---
 mypy.ini                         |  3 --
 src/xtgeo/grid3d/_grid_import.py | 55 ++++++++++++++++++++++----------
 2 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/mypy.ini b/mypy.ini
index 3f5779acd..d5aada172 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -60,9 +60,6 @@ ignore_errors = True
 [mypy-xtgeo.grid3d._grid_export]
 ignore_errors = True
 
-[mypy-xtgeo.grid3d._grid_import]
-ignore_errors = True
-
 [mypy-xtgeo.grid3d._grid_import_ecl]
 ignore_errors = True
 
diff --git a/src/xtgeo/grid3d/_grid_import.py b/src/xtgeo/grid3d/_grid_import.py
index ee824086e..75b26cf97 100644
--- a/src/xtgeo/grid3d/_grid_import.py
+++ b/src/xtgeo/grid3d/_grid_import.py
@@ -1,7 +1,11 @@
 """Grid import functions for various formats."""
+from __future__ import annotations
+
+from pathlib import Path
+from typing import Any, Literal
 
-import xtgeo
 from xtgeo.common import null_logger
+from xtgeo.common.sys import _XTGeoFile
 from xtgeo.grid3d import _grid_import_ecl, _grid_import_roff
 
 from . import _grid_import_xtgcpgeom
@@ -9,46 +13,65 @@
 logger = null_logger(__name__)
 
 
-def from_file(gfile, fformat=None, **kwargs):
+def from_file(
+    gfile: _XTGeoFile,
+    fformat: Literal[
+        "bgrdecl",
+        "egrid",
+        "fegrid",
+        "grdecl",
+        "guess",
+        "hdf",
+        "roff_ascii",
+        "roff_binary",
+        "xtg",
+    ]
+    | None = None,
+    **kwargs: Any,
+) -> dict[str, Any]:
     """Import grid geometry from file, and makes an instance of this class.
 
     Returns:
     dictionary of keyword arguments to be used in Grid constructor.
     """
-    if not isinstance(gfile, xtgeo._XTGeoFile):
+    if not isinstance(gfile, _XTGeoFile):
         raise RuntimeError("Error gfile must be a _XTGeoFile instance")
 
-    result = {}
+    result: dict[str, Any] = dict()
 
     result["filesrc"] = gfile.name
 
-    if fformat is None or fformat == "guess":
-        fformat = gfile.detect_fformat()
-    else:
-        fformat = gfile.generic_format_by_proposal(fformat)  # default
+    _fformat = (
+        gfile.detect_fformat()
+        if fformat is None or fformat == "guess"
+        else gfile.generic_format_by_proposal(fformat)  # default
+    )
 
     gfile.check_file(raiseerror=IOError, raisetext=f"Cannot access file {gfile.name}")
 
-    if fformat in ["roff_binary", "roff_ascii"]:
+    if _fformat in ["roff_binary", "roff_ascii"]:
         result.update(_grid_import_roff.import_roff(gfile, **kwargs))
-    elif fformat in ["egrid", "fegrid"]:
+    elif _fformat in ["egrid", "fegrid"]:
         result.update(
-            _grid_import_ecl.import_ecl_egrid(gfile, fileformat=fformat, **kwargs)
+            _grid_import_ecl.import_ecl_egrid(gfile, fileformat=_fformat, **kwargs)
         )
-    elif fformat == "grdecl":
+    elif _fformat == "grdecl":
         result.update(_grid_import_ecl.import_ecl_grdecl(gfile, **kwargs))
-    elif fformat == "bgrdecl":
+    elif _fformat == "bgrdecl":
         result.update(_grid_import_ecl.import_ecl_bgrdecl(gfile, **kwargs))
-    elif fformat == "xtg":
+    elif _fformat == "xtg":
         result.update(_grid_import_xtgcpgeom.import_xtgcpgeom(gfile, **kwargs))
-    elif fformat == "hdf":
+    elif _fformat == "hdf":
         result.update(_grid_import_xtgcpgeom.import_hdf5_cpgeom(gfile, **kwargs))
     else:
-        raise ValueError(f"Invalid file format: {fformat}")
+        raise ValueError(f"Invalid file format: {_fformat}")
 
     if gfile.memstream:
         result["name"] = "unknown"
     else:
+        # Mypy does not know that if gfile.memstream -> False
+        # then .file must be Path.
+        assert isinstance(gfile.file, Path)
         result["name"] = gfile.file.stem
 
     return result