Fix exception causes all over the codebase

Author: cool-RR

AUTHORS

@@ -233,6 +233,7 @@ Pulkit Goyal
 Punyashloka Biswal
 Quentin Pradet
 Ralf Schmitt
+Ram Rachum
 Ralph Giles
 Ran Benita
 Raphael Castaneda

changelog/7383.bugfix.rst

@@ -0,0 +1 @@
+Fixed exception causes all over the codebase, i.e. use `raise new_exception from old_exception` when wrapping an exception.

src/_pytest/_code/source.py

@@ -215,7 +215,7 @@ def compile(  # noqa: F811
             newex.offset = ex.offset
             newex.lineno = ex.lineno
             newex.text = ex.text
-            raise newex
+            raise newex from ex
         else:
             if flag & ast.PyCF_ONLY_AST:
                 assert isinstance(co, ast.AST)

src/_pytest/config/__init__.py

@@ -1189,8 +1189,10 @@ def getini(self, name: str):
     def _getini(self, name: str) -> Any:
         try:
             description, type, default = self._parser._inidict[name]
-        except KeyError:
-            raise ValueError("unknown configuration value: {!r}".format(name))
+        except KeyError as e:
+            raise ValueError(
+                "unknown configuration value: {!r}".format(name)
+            ) from e
         override_value = self._get_override_ini_value(name)
         if override_value is None:
             try:
@@ -1286,14 +1288,14 @@ def getoption(self, name: str, default=notset, skip: bool = False):
             if val is None and skip:
                 raise AttributeError(name)
             return val
-        except AttributeError:
+        except AttributeError as e:
             if default is not notset:
                 return default
             if skip:
                 import pytest
 
                 pytest.skip("no {!r} option found".format(name))
-            raise ValueError("no option named {!r}".format(name))
+            raise ValueError("no option named {!r}".format(name)) from e
 
     def getvalue(self, name, path=None):
         """ (deprecated, use getoption()) """

src/_pytest/config/argparsing.py

@@ -265,9 +265,9 @@ def __init__(self, *names: str, **attrs: Any) -> None:
         else:
             try:
                 self.dest = self._short_opts[0][1:]
-            except IndexError:
+            except IndexError as e:
                 self.dest = "???"  # Needed for the error repr.
-                raise ArgumentError("need a long or short option", self)
+                raise ArgumentError("need a long or short option", self) from e
 
     def names(self) -> List[str]:
         return self._short_opts + self._long_opts

src/_pytest/config/findpaths.py

@@ -26,7 +26,7 @@ def _parse_ini_config(path: py.path.local) -> iniconfig.IniConfig:
     try:
         return iniconfig.IniConfig(path)
     except iniconfig.ParseError as exc:
-        raise UsageError(str(exc))
+        raise UsageError(str(exc)) from exc
 
 
 def load_config_dict_from_file(

src/_pytest/debugging.py

@@ -28,10 +28,10 @@ def _validate_usepdb_cls(value: str) -> Tuple[str, str]:
     """Validate syntax of --pdbcls option."""
     try:
         modname, classname = value.split(":")
-    except ValueError:
+    except ValueError as e:
         raise argparse.ArgumentTypeError(
             "{!r} is not in the format 'modname:classname'".format(value)
-        )
+        ) from e
     return (modname, classname)
 
 
@@ -130,7 +130,7 @@ def _import_pdb_cls(cls, capman: "CaptureManager"):
                 value = ":".join((modname, classname))
                 raise UsageError(
                     "--pdbcls: could not import {!r}: {}".format(value, exc)
-                )
+                ) from exc
         else:
             import pdb
 

src/_pytest/fixtures.py

@@ -938,13 +938,13 @@ def _eval_scope_callable(
         # Type ignored because there is no typing mechanism to specify
         # keyword arguments, currently.
         result = scope_callable(fixture_name=fixture_name, config=config)  # type: ignore[call-arg] # noqa: F821
-    except Exception:
+    except Exception as e:
         raise TypeError(
             "Error evaluating {} while defining fixture '{}'.\n"
             "Expected a function with the signature (*, fixture_name, config)".format(
                 scope_callable, fixture_name
             )
-        )
+        ) from e
     if not isinstance(result, str):
         fail(
             "Expected {} to return a 'str' while defining fixture '{}', but it returned:\n"

src/_pytest/logging.py

@@ -487,13 +487,13 @@ def get_log_level_for_setting(config: Config, *setting_names: str) -> Optional[i
         log_level = log_level.upper()
     try:
         return int(getattr(logging, log_level, log_level))
-    except ValueError:
+    except ValueError as e:
         # Python logging does not recognise this as a logging level
         raise pytest.UsageError(
             "'{}' is not recognized as a logging level name for "
             "'{}'. Please consider passing the "
             "logging level num instead.".format(log_level, setting_name)
-        )
+        ) from e
 
 
 # run after terminalreporter/capturemanager are configured

src/_pytest/monkeypatch.py

@@ -73,20 +73,20 @@ def resolve(name: str) -> object:
             if expected == used:
                 raise
             else:
-                raise ImportError("import error in {}: {}".format(used, ex))
+                raise ImportError("import error in {}: {}".format(used, ex)) from ex
         found = annotated_getattr(found, part, used)
     return found
 
 
 def annotated_getattr(obj: object, name: str, ann: str) -> object:
     try:
         obj = getattr(obj, name)
-    except AttributeError:
+    except AttributeError as e:
         raise AttributeError(
             "{!r} object at {} has no attribute {!r}".format(
                 type(obj).__name__, ann, name
             )
-        )
+        ) from e
     return obj