New omegaconf_absolute_to_relative_paths parsing setting to enable backward compatibility of omegaconf+ parser mode

CHANGELOG.rst

@@ -27,6 +27,10 @@ Added
 - Argument to print help for dataclasses nested in types, e.g.
   ``Optional[Data]``, ``Union[Data1, Data2]`` (`#783
   <https://github.com/omni-us/jsonargparse/pull/783>`__).
+- ``set_parsing_settings`` now supports ``omegaconf_absolute_to_relative_paths``
+  to enable backward compatibility of ``omegaconf+`` parser mode by converting
+  absolute paths to relative in interpolations (`#774
+  <https://github.com/omni-us/jsonargparse/pull/774>`__).
 
 Fixed
 ^^^^^

DOCUMENTATION.rst

@@ -2475,7 +2475,10 @@ limitations of the ``omegaconf`` mode mentioned earlier. Instead of applying
 OmegaConf resolvers to each YAML config individually, the resolving is performed
 once at the end of the parsing process. As a result, in nested sub-configs,
 references to nodes must be either relative or parser-level absolute to function
-correctly.
+correctly. Alternatively, you can
+``set_parsing_settings(omegaconf_absolute_to_relative_paths=True)`` to enable
+automatic conversion of absolute paths to relative ones during parsing. Be aware
+that this automatic conversion does not work for every possible case.
 
 Based on community feedback, this mode may become the default ``omegaconf`` mode
 in version 5.0.0. This change would introduce a breaking modification, as

jsonargparse/_common.py

@@ -100,6 +100,7 @@ def parser_context(**kwargs):
     "validate_defaults": False,
     "parse_optionals_as_positionals": False,
     "stubs_resolver_allow_py_files": False,
+    "omegaconf_absolute_to_relative_paths": False,
 }
 
 
@@ -112,6 +113,7 @@ def set_parsing_settings(
     docstring_parse_attribute_docstrings: Optional[bool] = None,
     parse_optionals_as_positionals: Optional[bool] = None,
     stubs_resolver_allow_py_files: Optional[bool] = None,
+    omegaconf_absolute_to_relative_paths: Optional[bool] = None,
 ) -> None:
     """
     Modify settings that affect the parsing behavior.
@@ -136,6 +138,10 @@ def set_parsing_settings(
             parser. By default, this is False.
         stubs_resolver_allow_py_files: Whether the stubs resolver should search
             in ``.py`` files in addition to ``.pyi`` files.
+        omegaconf_absolute_to_relative_paths: If True, when loading configs
+            with ``omegaconf+`` parser mode, absolute interpolation paths are
+            converted to relative. This is only intended for backward
+            compatibility with ``omegaconf`` parser mode.
     """
     # validate_defaults
     if isinstance(validate_defaults, bool):
@@ -162,6 +168,13 @@ def set_parsing_settings(
         parsing_settings["stubs_resolver_allow_py_files"] = stubs_resolver_allow_py_files
     elif stubs_resolver_allow_py_files is not None:
         raise ValueError(f"stubs_resolver_allow_py_files must be a boolean, but got {stubs_resolver_allow_py_files}.")
+    # omegaconf_absolute_to_relative_paths
+    if isinstance(omegaconf_absolute_to_relative_paths, bool):
+        parsing_settings["omegaconf_absolute_to_relative_paths"] = omegaconf_absolute_to_relative_paths
+    elif omegaconf_absolute_to_relative_paths is not None:
+        raise ValueError(
+            f"omegaconf_absolute_to_relative_paths must be a boolean, but got {omegaconf_absolute_to_relative_paths}."
+        )
 
 
 def get_parsing_setting(name: str):

jsonargparse/_loaders_dumpers.py

@@ -339,7 +339,7 @@ def set_omegaconf_loader(mode="omegaconf"):
     if omegaconf_support and mode not in loaders:
         from ._optionals import get_omegaconf_loader
 
-        loader = yaml_load if mode == "omegaconf+" else get_omegaconf_loader()
+        loader = get_omegaconf_loader(mode)
         set_loader(mode, loader, get_loader_exceptions("yaml"))
 
 

jsonargparse/_optionals.py

@@ -2,10 +2,12 @@
 
 import inspect
 import os
+import re
 from contextlib import contextmanager
+from copy import deepcopy
 from importlib.metadata import version
 from importlib.util import find_spec
-from typing import Optional, Union
+from typing import List, Optional, Union
 
 __all__ = [
     "_get_config_read_mode",
@@ -266,7 +268,7 @@ def get_doc_short_description(function_or_class, method_name=None, logger=None):
     return None
 
 
-def get_omegaconf_loader():
+def get_omegaconf_loader(mode):
     """Returns a yaml loader function based on OmegaConf which supports variable interpolation."""
     import io
 
@@ -275,6 +277,22 @@ def get_omegaconf_loader():
     with missing_package_raise("omegaconf", "get_omegaconf_loader"):
         from omegaconf import OmegaConf
 
+    assert mode in {"omegaconf", "omegaconf+"}
+
+    if mode == "omegaconf+":
+        from ._common import get_parsing_setting
+
+        if not get_parsing_setting("omegaconf_absolute_to_relative_paths"):
+            return yaml_load
+
+        def omegaconf_plus_load(value):
+            value = yaml_load(value)
+            if isinstance(value, dict):
+                value = omegaconf_absolute_to_relative_paths(value)
+            return value
+
+        return omegaconf_plus_load
+
     def omegaconf_load(value):
         value_pyyaml = yaml_load(value)
         if isinstance(value_pyyaml, (str, int, float, bool)) or value_pyyaml is None:
@@ -302,6 +320,57 @@ def omegaconf_apply(parser, cfg):
     return parser._apply_actions(cfg_dict)
 
 
+def omegaconf_tokenize(path: str) -> List[str]:
+    """Very small tokenizer: 'a.b[0].c' -> ['a','b','0','c']."""
+    return [t for t in path.replace("]", "").replace("[", ".").split(".") if t]
+
+
+def omegaconf_tokens_to_path(tokens: List[str]) -> str:
+    """Render tokens back to a normalized path: ['a','0','b'] -> 'a[0].b'."""
+    s = ""
+    for t in tokens:
+        if t.isdigit():
+            s += f"[{t}]"
+        else:
+            s += ("" if s == "" else ".") + t
+    return s
+
+
+def omegaconf_absolute_to_relative_paths(data: dict) -> dict:
+    """
+    Return a new nested dict/list where absolute ${...} interpolations
+    are rewritten to relative form from the node where they appear.
+    """
+    data = deepcopy(data)
+
+    regex_absolute_path = re.compile(r"\$\{([a-zA-Z][a-zA-Z0-9[\]_.]*)\}")
+
+    def _walk(node, current_path: List[Union[str, int]]):
+        if isinstance(node, dict):
+            return {k: _walk(v, current_path + [k]) for k, v in node.items()}
+        if isinstance(node, list):
+            return [_walk(v, current_path + [i]) for i, v in enumerate(node)]
+
+        if isinstance(node, str):
+
+            def _replace(m: re.Match) -> str:
+                dst_tokens = omegaconf_tokenize(m.group(1))
+                # compute common prefix length
+                i = 0
+                while i < len(current_path) and i < len(dst_tokens) and str(current_path[i]) == dst_tokens[i]:
+                    i += 1
+                up = max(1, len(current_path) - i)
+                dots = "." * up
+                down = omegaconf_tokens_to_path(dst_tokens[i:])
+                return "${" + dots + down + "}"
+
+            return regex_absolute_path.sub(_replace, node)
+
+        return node
+
+    return _walk(data, [])
+
+
 annotated_alias = typing_extensions_import("_AnnotatedAlias")
 
 

jsonargparse_tests/test_omegaconf.py

@@ -10,9 +10,9 @@
 import pytest
 
 from jsonargparse import ArgumentParser, Namespace
-from jsonargparse._common import parser_context
+from jsonargparse._common import parser_context, set_parsing_settings
 from jsonargparse._loaders_dumpers import loaders, yaml_dump
-from jsonargparse._optionals import omegaconf_support
+from jsonargparse._optionals import omegaconf_absolute_to_relative_paths, omegaconf_support
 from jsonargparse.typing import Path_fr
 from jsonargparse_tests.conftest import get_parser_help
 
@@ -25,6 +25,12 @@
 )
 
 
+@pytest.fixture(autouse=True)
+def patch_loaders():
+    with patch.dict("jsonargparse._loaders_dumpers.loaders"):
+        yield
+
+
 @pytest.mark.skipif(
     not (omegaconf_support and "JSONARGPARSE_OMEGACONF_FULL_TEST" in os.environ),
     reason="only for omegaconf as the yaml loader",
@@ -57,19 +63,23 @@ def test_omegaconf_interpolation(mode):
 
 
 @skip_if_omegaconf_unavailable
-@pytest.mark.parametrize("mode", ["omegaconf", "omegaconf+"])
+@pytest.mark.parametrize("mode", ["omegaconf", "omegaconf+", "omegaconf+absolute"])
+@patch.dict("jsonargparse._common.parsing_settings")
 def test_omegaconf_interpolation_in_subcommands(mode, parser, subparser):
     subparser.add_argument("--config", action="config")
     subparser.add_argument("--source", type=str)
     subparser.add_argument("--target", type=str)
 
-    parser.parser_mode = mode
+    if mode == "omegaconf+absolute":
+        set_parsing_settings(omegaconf_absolute_to_relative_paths=True)
+
+    parser.parser_mode = mode.replace("absolute", "")
     subcommands = parser.add_subcommands()
     subcommands.add_subcommand("sub", subparser)
 
     config = {
         "source": "hello",
-        "target": "${source}" if mode == "omegaconf" else "${.source}",
+        "target": "${.source}" if mode == "omegaconf+" else "${source}",
     }
     cfg = parser.parse_args(["sub", f"--config={yaml_dump(config)}"])
     assert cfg.sub.target == "hello"
@@ -193,3 +203,24 @@ def test_omegaconf_inf_nan(parser):
     assert math.isnan(cfg.c)
     assert cfg.d == float("inf")
     assert cfg.e == float("-inf")
+
+
+@skip_if_omegaconf_unavailable
+def test_omegaconf_absolute_to_relative_paths():
+    data = {
+        "a": "x",
+        "b": "prefix ${a} suffix",
+        "c": {"d": "${b}", "e": "${c.d}"},
+        "f": [10, "${c.e}", "${..b}"],
+        "g": "${env:USER}",
+        "h": "${f[0]}",
+    }
+    expected = {
+        "a": "x",
+        "b": "prefix ${.a} suffix",
+        "c": {"d": "${..b}", "e": "${.d}"},
+        "f": [10, "${..c.e}", "${..b}"],
+        "g": "${env:USER}",
+        "h": "${.f[0]}",
+    }
+    assert omegaconf_absolute_to_relative_paths(data) == expected

jsonargparse_tests/test_parsing_settings.py

@@ -195,3 +195,11 @@ def test_optionals_as_positionals_unsupported_arguments(parser):
 def test_set_stubs_resolver_allow_py_files_failure():
     with pytest.raises(ValueError, match="stubs_resolver_allow_py_files must be a boolean"):
         set_parsing_settings(stubs_resolver_allow_py_files="invalid")
+
+
+# omegaconf_absolute_to_relative_paths
+
+
+def test_set_omegaconf_absolute_to_relative_paths_failure():
+    with pytest.raises(ValueError, match="omegaconf_absolute_to_relative_paths must be a boolean"):
+        set_parsing_settings(omegaconf_absolute_to_relative_paths="invalid")