Skip Instances with --collect-only

changelog/4358.removal.rst

@@ -14,3 +14,5 @@ it was not really possible to detect when the functionality was being used expli
 The extra ``::()`` might have been removed in some places internally already,
 which then led to confusion in places where it was expected, e.g. with
 ``--deselect`` (`#4127 <https://github.com/pytest-dev/pytest/issues/4127>`_).
+
+Test class instances are also not listed with ``--collect-only`` anymore.

src/_pytest/terminal.py

@@ -617,8 +617,8 @@ class TerminalReporter(object):
                 stack.pop()
             for col in needed_collectors[len(stack) :]:
                 stack.append(col)
-                # if col.name == "()":
-                #    continue
+                if col.name == "()":  # Skip Instances.
+                    continue
                 indent = (len(stack) - 1) * "  "
                 self._tw.line("%s%s" % (indent, col))
 

testing/python/collect.py

@@ -1408,9 +1408,7 @@ def test_customize_through_attributes(testdir):
     """
     )
     result = testdir.runpytest("--collect-only")
-    result.stdout.fnmatch_lines(
-        ["*MyClass*", "*MyInstance*", "*MyFunction*test_hello*"]
-    )
+    result.stdout.fnmatch_lines(["*MyClass*", "*MyFunction*test_hello*"])
 
 
 def test_unorderable_types(testdir):