Refactor TOML error handling and improve pyproject reading logic

- Introduced `InvalidTomlError` to handle parsing errors in TOML files.
- Simplified the `read_pyproject` function by removing unnecessary exception handling for file not found.
- Updated exception handling in version inference to use `InvalidTomlError` for better clarity in error logging.

Author: RonnyPfannschmidt

src/setuptools_scm/_integration/pyproject_reading.py

@@ -127,10 +127,7 @@ def read_pyproject(
     tool_name: str = "setuptools_scm",
     canonical_build_package_name: str = "setuptools-scm",
 ) -> PyProjectData:
-    try:
-        defn = read_toml_content(path)
-    except FileNotFoundError:
-        raise
+    defn = read_toml_content(path)
 
     requires: list[str] = defn.get("build-system", {}).get("requires", [])
     is_required = has_build_package(requires, canonical_build_package_name)

src/setuptools_scm/_integration/setuptools.py

@@ -12,6 +12,7 @@
 from .pyproject_reading import PyProjectData
 from .pyproject_reading import read_pyproject
 from .setup_cfg import _dist_name_from_legacy
+from .toml import InvalidTomlError
 from .version_inference import get_version_inference_config
 
 log = logging.getLogger(__name__)
@@ -97,7 +98,7 @@ def version_keyword(
             pyproject_data = PyProjectData.empty(
                 Path("pyproject.toml"), "setuptools_scm"
             )
-        except (LookupError, ValueError) as e:
+        except InvalidTomlError as e:
             log.debug("Configuration issue in pyproject.toml: %s", e)
             return
 
@@ -134,7 +135,7 @@ def infer_version(
         except FileNotFoundError:
             log.debug("pyproject.toml not found, skipping infer_version")
             return
-        except (LookupError, ValueError) as e:
+        except InvalidTomlError as e:
             log.debug("Configuration issue in pyproject.toml: %s", e)
             return
 

src/setuptools_scm/_integration/toml.py

@@ -29,6 +29,10 @@
 TOML_LOADER: TypeAlias = Callable[[str], TOML_RESULT]
 
 
+class InvalidTomlError(ValueError):
+    """Raised when TOML data cannot be parsed."""
+
+
 def read_toml_content(path: Path, default: TOML_RESULT | None = None) -> TOML_RESULT:
     try:
         data = path.read_text(encoding="utf-8")
@@ -39,7 +43,10 @@ def read_toml_content(path: Path, default: TOML_RESULT | None = None) -> TOML_RE
             log.debug("%s missing, presuming default %r", path, default)
             return default
     else:
-        return load_toml(data)
+        try:
+            return load_toml(data)
+        except Exception as e:  # tomllib/tomli raise different decode errors
+            raise InvalidTomlError(f"Invalid TOML in {path}") from e
 
 
 class _CheatTomlData(TypedDict):
@@ -52,8 +59,11 @@ def load_toml_or_inline_map(data: str | None) -> dict[str, Any]:
     """
     if not data:
         return {}
-    elif data[0] == "{":
-        data = "cheat=" + data
-        loaded: _CheatTomlData = cast(_CheatTomlData, load_toml(data))
-        return loaded["cheat"]
-    return load_toml(data)
+    try:
+        if data[0] == "{":
+            data = "cheat=" + data
+            loaded: _CheatTomlData = cast(_CheatTomlData, load_toml(data))
+            return loaded["cheat"]
+        return load_toml(data)
+    except Exception as e:  # tomllib/tomli raise different decode errors
+        raise InvalidTomlError("Invalid TOML content") from e