limit the number of elements shown for API use suggestion; #3819

Author: vreuter

hypothesis-python/src/hypothesis/core.py

@@ -1025,14 +1025,11 @@ def _execute_once_for_engine(self, data: ConjectureData) -> None:
                 # path for test runs that fail.
                 if isinstance(e, TypeError) and "SearchStrategy" in str(e):
                     try:
-                        bad_strat_repr = data._sampled_from_strategy_repr  # type: ignore[attr-defined]
+                        suggestion = data._sampled_from_all_strategies_elements_message
                     except AttributeError:
                         pass
                     else:
-                        add_note(
-                            e,
-                            f"sample_from was given a collection of strategies: {bad_strat_repr}. Was one_of intended?",
-                        )
+                        add_note(e, suggestion)
                 tb = get_trimmed_traceback()
                 info = data.extra_information
                 info._expected_traceback = format_exception(e, tb)  # type: ignore

hypothesis-python/src/hypothesis/strategies/_internal/strategies.py

@@ -531,7 +531,16 @@ def do_draw(self, data):
         if isinstance(result, SearchStrategy) and all(
             isinstance(x, SearchStrategy) for x in self.elements
         ):
-            data._sampled_from_strategy_repr = repr(self)
+            max_num_strats = 3
+            preamble = (
+                f"(first {max_num_strats}) "
+                if len(self.elements) > max_num_strats
+                else ""
+            )
+            strat_reprs = ", ".join(
+                map(get_pretty_function_description, self.elements[:max_num_strats])
+            )
+            data._sampled_from_all_strategies_elements_message = f"sample_from was given a collection of strategies: {preamble}{strat_reprs}. Was one_of intended?"
         if result is filter_not_satisfied:
             data.mark_invalid(f"Aborted test because unable to satisfy {self!r}")
         return result