From 54777d60d80157368944a0be01ce3add737fcc72 Mon Sep 17 00:00:00 2001
From: Liam DeVoe <orionldevoe@gmail.com>
Date: Sat, 7 Dec 2024 02:30:21 -0500
Subject: [PATCH] recommend remedies in unsatsisfiable

---
 hypothesis-python/src/hypothesis/core.py      | 27 ++++++++++++++++++-
 .../hypothesis/internal/conjecture/engine.py  |  8 +++++-
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/hypothesis-python/src/hypothesis/core.py b/hypothesis-python/src/hypothesis/core.py
index d60fcab01f..306f6497bb 100644
--- a/hypothesis-python/src/hypothesis/core.py
+++ b/hypothesis-python/src/hypothesis/core.py
@@ -1231,8 +1231,33 @@ def run_engine(self):
             )
         else:
             if runner.valid_examples == 0:
+                explanations = []
+                # use a somewhat arbitrary cutoff to avoid recommending spurious
+                # fixes.
+                # eg, a few invalid examples from internal filters when the
+                # problem is the user generating large inputs, or a
+                # few overruns during internal mutation when the problem is
+                # impossible user filters/assumes.
+                if runner.invalid_examples > min(20, runner.call_count // 5):
+                    explanations.append(
+                        f"{runner.invalid_examples} of {runner.call_count} "
+                        "examples failed a .filter() or assume() condition. Try "
+                        "making your filters or assumes less strict, or rewrite "
+                        "using strategy parameters: "
+                        "st.integers().filter(lambda x: x > 0) fails less often "
+                        "(that is, never) when rewritten as st.integers(min_value=1)."
+                    )
+                if runner.overrun_examples > min(20, runner.call_count // 5):
+                    explanations.append(
+                        f"{runner.overrun_examples} of {runner.call_count} "
+                        "examples were too large to finish generating. Try "
+                        "reducing the size of your inputs."
+                    )
                 rep = get_pretty_function_description(self.test)
-                raise Unsatisfiable(f"Unable to satisfy assumptions of {rep}")
+                raise Unsatisfiable(
+                    f"Unable to satisfy assumptions of {rep}. "
+                    f"{' Also, '.join(explanations)}"
+                )
 
         # If we have not traced executions, warn about that now (but only when
         # we'd expect to do so reliably, i.e. on CPython>=3.12)
diff --git a/hypothesis-python/src/hypothesis/internal/conjecture/engine.py b/hypothesis-python/src/hypothesis/internal/conjecture/engine.py
index a5c388683b..894a8b67ee 100644
--- a/hypothesis-python/src/hypothesis/internal/conjecture/engine.py
+++ b/hypothesis-python/src/hypothesis/internal/conjecture/engine.py
@@ -228,6 +228,8 @@ def __init__(
         self.call_count: int = 0
         self.misaligned_count: int = 0
         self.valid_examples: int = 0
+        self.invalid_examples = 0
+        self.overrun_examples = 0
         self.random: Random = random or Random(getrandbits(128))
         self.database_key: Optional[bytes] = database_key
         self.ignore_limits: bool = ignore_limits
@@ -567,8 +569,12 @@ def test_function(self, data: ConjectureData) -> None:
                     assert not isinstance(data_as_result, _Overrun)
                     self.best_examples_of_observed_targets[k] = data_as_result
 
-        if data.status == Status.VALID:
+        if data.status is Status.VALID:
             self.valid_examples += 1
+        if data.status is Status.INVALID:
+            self.invalid_examples += 1
+        if data.status is Status.OVERRUN:
+            self.overrun_examples += 1
 
         if data.status == Status.INTERESTING:
             if not self.using_hypothesis_backend: