added exceptiongroup to pre-commit-config, moved away from tuple to directly defining BaseExceptionGroup, added block comment, added match line for inner exception, changked mark.skipif to importorskip to not need top-level import, changed tox.ini a bit - only uncovered should now be py37 without exceptiongroup, due to hypothesis

.pre-commit-config.yaml

@@ -68,6 +68,7 @@ repos:
           - packaging
           - tomli
           - types-pkg_resources
+          - exceptiongroup>=1.0.0rc8
 -   repo: local
     hooks:
     -   id: rst

src/_pytest/_code/code.py

@@ -56,18 +56,14 @@ if TYPE_CHECKING:
 
     _TracebackStyle = Literal["long", "short", "line", "no", "native", "value", "auto"]
 
-ExceptionGroupTypes: Tuple[Type[BaseException], ...] = ()
-
-if sys.version_info >= (3, 11):
-    ExceptionGroupTypes = (BaseExceptionGroup,)  # type: ignore # noqa: F821
+BaseExceptionGroup: Optional[Type[BaseException]]
 try:
-    import exceptiongroup
-
-    ExceptionGroupTypes += (exceptiongroup.BaseExceptionGroup,)
-except ModuleNotFoundError:
-    # no backport installed - if <3.11 that means programs can't raise exceptiongroups
-    # so we don't need to handle it
-    pass
+    BaseExceptionGroup = BaseExceptionGroup  # type: ignore
+except NameError:
+    try:
+        from exceptiongroup import BaseExceptionGroup
+    except ModuleNotFoundError:
+        BaseExceptionGroup = None
 
 
 class Code:
@@ -937,7 +933,10 @@ class FormattedExcinfo:
         while e is not None and id(e) not in seen:
             seen.add(id(e))
             if excinfo_:
-                if isinstance(e, tuple(ExceptionGroupTypes)):
+                # Fall back to native traceback as a temporary workaround until
+                # full support for exception groups added to ExceptionInfo.
+                # See https://github.com/pytest-dev/pytest/issues/9159
+                if BaseExceptionGroup is not None and isinstance(e, BaseExceptionGroup):
                     reprtraceback: Union[
                         ReprTracebackNative, ReprTraceback
                     ] = ReprTracebackNative(

testing/code/test_excinfo.py

@@ -11,11 +11,6 @@ from typing import Tuple
 from typing import TYPE_CHECKING
 from typing import Union
 
-try:
-    import exceptiongroup  # noqa (referred to in strings)
-except ModuleNotFoundError:
-    pass
-
 import _pytest
 import pytest
 from _pytest._code.code import ExceptionChainRepr
@@ -28,6 +23,7 @@ from _pytest.pathlib import import_path
 from _pytest.pytester import LineMatcher
 from _pytest.pytester import Pytester
 
+
 if TYPE_CHECKING:
     from _pytest._code.code import _TracebackStyle
 
@@ -1526,7 +1522,12 @@ def _exceptiongroup_common(
     """
     pytester.makepyfile(test_excgroup=filestr)
     result = pytester.runpytest()
-    match_lines = [
+    match_lines = []
+    if inner_chain in ("another", "from"):
+        match_lines.append(r"SyntaxError: <no detail available>")
+
+    match_lines += [
+        r"  + Exception Group Traceback (most recent call last):",
         rf"  \| {pre2}BaseExceptionGroup: Oops \(2 sub-exceptions\)",
         r"    \| ValueError: From f\(\)",
         r"    \| BaseException: From g\(\)",
@@ -1550,10 +1551,8 @@ def test_native_exceptiongroup(pytester: Pytester, outer_chain, inner_chain) ->
     _exceptiongroup_common(pytester, outer_chain, inner_chain, native=True)
 
 
-@pytest.mark.skipif(
-    "exceptiongroup" not in sys.modules, reason="exceptiongroup not installed"
-)
 @pytest.mark.parametrize("outer_chain", ["none", "from", "another"])
 @pytest.mark.parametrize("inner_chain", ["none", "from", "another"])
 def test_exceptiongroup(pytester: Pytester, outer_chain, inner_chain) -> None:
+    pytest.importorskip("exceptiongroup")
     _exceptiongroup_common(pytester, outer_chain, inner_chain, native=False)

tox.ini

@@ -9,9 +9,9 @@ envlist =
     py39
     py310
     py311
-    py311-exceptiongroup
     pypy3
-    py37-{pexpect,xdist,unittestextras,numpy,pluggymain,exceptiongroup}
+    py37-{pexpect,xdist,unittestextras,numpy,pluggymain}
+    py311-exceptiongroup
     doctesting
     plugins
     py37-freeze