fix(filemodel): ResolveRelativeMode is incorrectly set when reading a…

… model with 'pathsRelativeToParent' set to false (#259)

* Add separate relative mode deduction when reading a model

* Add additional documentation to FileModel init

* Fix typo in comment

* Add additional information detailing the data param

* autoformat: isort & black

* Docstring link in documentation only.

Co-authored-by: Arthur van Dam <arthurvd@gmail.com>

hydrolib/core/basemodel.py

@@ -546,13 +546,19 @@ def __init__(self, filepath: Optional[Path] = None, *args, **kwargs):
             self._absolute_anchor_path = context.get_current_parent()
             loading_path = context.resolve(filepath)
 
-            context.push_new_parent(filepath.parent, self._relative_mode)
             logger.info(f"Loading data from {filepath}")
 
             data = self._load(loading_path)
             data["filepath"] = filepath
             kwargs.update(data)
 
+            # Note: the relative mode needs to be obtained from the data directly
+            # because self._relative_mode has not been resolved yet (this is done as
+            # part of the __init__), however during the __init__ we need to already
+            # have pushed the new parent. As such we cannot move this call later.
+            relative_mode = self._get_relative_mode_from_data(data)
+            context.push_new_parent(filepath.parent, relative_mode)
+
             super().__init__(*args, **kwargs)
             self._post_init_load()
 
@@ -778,6 +784,26 @@ def _relative_mode(self) -> ResolveRelativeMode:
         """Gets the ResolveRelativeMode of this FileModel.
 
         Returns:
-            ResolveRelativeMode: The ResolveRelativ
+            ResolveRelativeMode: The ResolveRelativeMode of this FileModel
+        """
+        return ResolveRelativeMode.ToParent
+
+    @classmethod
+    def _get_relative_mode_from_data(cls, data: Dict[str, Any]) -> ResolveRelativeMode:
+        """Gets the ResolveRelativeMode of this FileModel based on the provided data.
+
+        Note that by default, data is not used, and FileModels are always relative to
+        the parent. In exceptional cases, the relative mode can be dependent on the
+        data (i.e. the unvalidated/parsed dictionary fed into the pydantic basemodel).
+        As such the data is provided for such classes where the relative mode is
+        dependent on the state (e.g. the [FMModel][hydrolib.core.io.mdu.models.FMModel]).
+
+        Args:
+            data (Dict[str, Any]):
+                The unvalidated/parsed data which is fed to the pydantic base model,
+                used to determine the ResolveRelativeMode.
+
+        Returns:
+            ResolveRelativeMode: The ResolveRelativeMode of this FileModel
         """
         return ResolveRelativeMode.ToParent

hydrolib/core/io/mdu/models.py

@@ -1,5 +1,5 @@
 from pathlib import Path
-from typing import Dict, List, Literal, Optional, Union
+from typing import Any, Dict, List, Literal, Optional, Union
 
 from pydantic import Field
 
@@ -552,3 +552,28 @@ def _relative_mode(self) -> ResolveRelativeMode:
             return ResolveRelativeMode.ToParent
         else:
             return ResolveRelativeMode.ToAnchor
+
+    @classmethod
+    def _get_relative_mode_from_data(cls, data: Dict[str, Any]) -> ResolveRelativeMode:
+        """Gets the ResolveRelativeMode of this FileModel based on the provided data.
+
+        The ResolveRelativeMode of the FMModel is determined by the
+        'pathsRelativeToParent' property of the 'General' category.
+
+        Args:
+            data (Dict[str, Any]):
+                The unvalidated/parsed data which is fed to the pydantic base model,
+                used to determine the ResolveRelativeMode.
+
+        Returns:
+            ResolveRelativeMode: The ResolveRelativeMode of this FileModel
+        """
+        if not (general := data.get("general", None)):
+            return ResolveRelativeMode.ToParent
+        if not (relative_to_parent := general.get("pathsrelativetoparent", None)):
+            return ResolveRelativeMode.ToParent
+
+        if relative_to_parent == "0":
+            return ResolveRelativeMode.ToAnchor
+        else:
+            return ResolveRelativeMode.ToParent