Allow contibuting additional global variables for skipif/xfail

src/_pytest/hookspec.py

@@ -808,6 +808,16 @@ def pytest_warning_recorded(
     """
 
 
+# -------------------------------------------------------------------------
+# Hooks for influencing skipping
+# -------------------------------------------------------------------------
+def pytest_skipif_additional_globals() -> Dict[str, Any]:
+    """Called when constructing the globals dictionary used for
+    evaluating skipif contditions.
+    Return a dictionary of additional globals to add.
+    """
+
+
 # -------------------------------------------------------------------------
 # error handling and internal debugging hooks
 # -------------------------------------------------------------------------

src/_pytest/skipping.py

@@ -101,6 +101,10 @@ def evaluate_condition(item: Item, mark: Mark, condition: object) -> Tuple[bool,
             "platform": platform,
             "config": item.config,
         }
+        for dictionary in item.config.hook.pytest_skipif_additional_globals():
+            if not isinstance(dictionary, dict) or not dictionary:
+                continue
+            globals_.update(dictionary)
         if hasattr(item, "obj"):
             globals_.update(item.obj.__globals__)  # type: ignore[attr-defined]
         try:

testing/test_skipping.py

@@ -153,6 +153,33 @@ def test_func(self):
         assert skipped
         assert skipped.reason == "condition: config._hackxyz"
 
+    def test_skipif_additional_globals(self, testdir):
+        testdir.makeconftest(
+            """
+            import pytest
+
+            def pytest_skipif_additional_globals():
+                return {"color": "green"}
+            """
+        )
+        p = testdir.makepyfile(
+            """
+            import pytest
+
+            @pytest.mark.skipif("color == 'green'")
+            def test_1():
+                assert True
+
+            @pytest.mark.skipif("color == 'red'")
+            def test_2():
+                assert True
+        """
+        )
+        res = testdir.runpytest(p)
+        assert res.ret == 0
+        res.stdout.fnmatch_lines(["*1 skipped*"])
+        res.stdout.fnmatch_lines(["*1 passed*"])
+
 
 class TestXFail:
     @pytest.mark.parametrize("strict", [True, False])