Properly escape interpolation-like strings in resolved configs

.pre-commit-config.yaml

@@ -1,24 +1,25 @@
+default_language_version:
+      python: python3.8
+
 repos:
-  - repo: https://github.com/timothycrosley/isort
-    rev: 5.0.9
+  - repo: https://github.com/PyCQA/isort
+    rev: 5.12.0
     hooks:
       - id: isort
 
   - repo: https://github.com/psf/black
-    rev: 20.8b1
+    rev: 23.7.0
     hooks:
       - id: black
-        language_version: python3.8
 
-  - repo: https://gitlab.com/pycqa/flake8
-    rev: 3.7.9
+  - repo: https://github.com/PyCQA/flake8
+    rev: 6.0.0
     hooks:
       - id: flake8
-        additional_dependencies: [-e, 'git+https://github.com/pycqa/pyflakes.git@1911c20#egg=pyflakes']
 
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.931
+    rev: v1.4.1
     hooks:
       - id: mypy
         args: [--strict]
-        additional_dependencies: ['pytest']
+        additional_dependencies: ['attrs', 'pytest']

omegaconf/_impl.py

@@ -10,10 +10,13 @@
     _get_value,
     is_primitive_container,
     is_structured_config,
+    maybe_escape,
 )
 
 
-def _resolve_container_value(cfg: Container, key: Any) -> None:
+def _resolve_container_value(
+    cfg: Container, key: Any, escape_interpolation_strings: bool
+) -> None:
     node = cfg._get_child(key)
     assert isinstance(node, Node)
     if node._is_interpolation():
@@ -23,7 +26,7 @@ def _resolve_container_value(cfg: Container, key: Any) -> None:
             node._set_value(MISSING)
         else:
             if isinstance(resolved, Container):
-                _resolve(resolved)
+                _resolve(resolved, escape_interpolation_strings)
             if isinstance(resolved, InterpolationResultNode):
                 resolved_value = _get_value(resolved)
                 if is_primitive_container(resolved_value) or is_structured_config(
@@ -33,28 +36,34 @@ def _resolve_container_value(cfg: Container, key: Any) -> None:
             if isinstance(resolved, Container) and isinstance(node, ValueNode):
                 cfg[key] = resolved
             else:
-                node._set_value(_get_value(resolved))
+                val = _get_value(resolved)
+                if escape_interpolation_strings:
+                    val = maybe_escape(val)
+                node._set_value(val)
     else:
-        _resolve(node)
+        _resolve(node, escape_interpolation_strings)
 
 
-def _resolve(cfg: Node) -> Node:
+def _resolve(cfg: Node, escape_interpolation_strings: bool) -> Node:
     assert isinstance(cfg, Node)
     if cfg._is_interpolation():
         try:
             resolved = cfg._dereference_node()
         except InterpolationToMissingValueError:
             cfg._set_value(MISSING)
         else:
-            cfg._set_value(resolved._value())
+            val = resolved._value()
+            if escape_interpolation_strings:
+                val = maybe_escape(val)
+            cfg._set_value(val)
 
     if isinstance(cfg, DictConfig):
         for k in cfg.keys():
-            _resolve_container_value(cfg, k)
+            _resolve_container_value(cfg, k, escape_interpolation_strings)
 
     elif isinstance(cfg, ListConfig):
         for i in range(len(cfg)):
-            _resolve_container_value(cfg, i)
+            _resolve_container_value(cfg, i, escape_interpolation_strings)
 
     return cfg
 

omegaconf/_utils.py

@@ -683,6 +683,43 @@ def is_primitive_container(obj: Any) -> bool:
     return is_primitive_list(obj) or is_primitive_dict(obj)
 
 
+def maybe_escape(value: Any) -> Any:
+    """Escape interpolation strings and return other values unchanged.
+
+    When the input value is an interpolation string, the returned value is such that
+    it yields the original input string when resolved.
+    """
+    if not isinstance(value, str) or not _is_interpolation_string(
+        value, strict_interpolation_validation=False
+    ):
+        return value
+    start = 0
+    tokens = []
+    while True:
+        # Find next ${ that needs escaping.
+        first_inter = value.find("${", start)
+        if first_inter < 0:
+            tokens.append(value[start:])  # ensure we keep the end of the string
+            break
+        # Any backslash that comes before ${ will need to be escaped as well.
+        count_esc = 0
+        while (
+            first_inter - count_esc - 1 >= 0
+            and value[first_inter - count_esc - 1] == "\\"
+        ):
+            count_esc += 1
+        tokens += [
+            # Characters that need not be changed.
+            value[start : first_inter - count_esc],
+            # Escaped backslashes before the interpolation.
+            "\\" * (count_esc * 2),
+            # Escaped interpolation.
+            "\\${",
+        ]
+        start = first_inter + 2
+    return "".join(tokens)
+
+
 def get_list_element_type(ref_type: Optional[Type[Any]]) -> Any:
     args = getattr(ref_type, "__args__", None)
     if ref_type is not List and args is not None and args[0]:

omegaconf/omegaconf.py

@@ -785,7 +785,7 @@ def to_yaml(cfg: Any, *, resolve: bool = False, sort_keys: bool = False) -> str:
         )
 
     @staticmethod
-    def resolve(cfg: Container) -> None:
+    def resolve(cfg: Container, escape_interpolation_strings: bool = False) -> None:
         """
         Resolves all interpolations in the given config object in-place.
 
@@ -800,7 +800,10 @@ def resolve(cfg: Container) -> None:
             raise ValueError(
                 f"Invalid config type ({type(cfg).__name__}), expected an OmegaConf Container"
             )
-        omegaconf._impl._resolve(cfg)
+        omegaconf._impl._resolve(cfg, escape_interpolation_strings=True)
+        if not escape_interpolation_strings:
+            # Do a second pass without escaping.
+            omegaconf._impl._resolve(cfg, escape_interpolation_strings=False)
 
     @staticmethod
     def missing_keys(cfg: Any) -> Set[str]:

requirements/dev.txt

@@ -1,12 +1,12 @@
 -r base.txt
 -r docs.txt
 attrs
-black
+black>=23.7.0
 build
 coveralls
-flake8>=4
-isort~=5.0
-mypy
+flake8>=6.0.0
+isort>=5.12.0
+mypy>=1.4.1
 nox
 pre-commit
 pyflakes
@@ -15,6 +15,6 @@ pytest-benchmark
 pytest-lazy-fixture
 pytest-mock
 towncrier
+types-setuptools  # makes mypy happy
 twine
 pydevd
-

setup.cfg

@@ -2,7 +2,7 @@
 test=pytest
 
 [mypy]
-python_version = 3.7
+python_version = 3.8
 mypy_path=.stubs
 exclude = build/