From b6c6f7f2b62b06c2ecd7b95dbe6955330a1c7221 Mon Sep 17 00:00:00 2001
From: Adam Reichold <adam.reichold@t-online.de>
Date: Tue, 13 Sep 2022 20:49:20 +0200
Subject: [PATCH] Fix #2615 by relaxing the type check in extract_sequence.

This allows us to handle types like one-dimensional NumPy arrays which implement
just enough of the sequence protocol to support the extract_sequence function
but are not an instance of the sequence ABC.
---
 src/types/sequence.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/types/sequence.rs b/src/types/sequence.rs
index 54de7158..af7cd0c5 100644
--- a/src/types/sequence.rs
+++ b/src/types/sequence.rs
@@ -299,7 +299,16 @@ fn extract_sequence<'s, T>(obj: &'s PyAny) -> PyResult<Vec<T>>
 where
     T: FromPyObject<'s>,
 {
-    let seq = <PySequence as PyTryFrom>::try_from(obj)?;
+    // Types that pass `PySequence_Check` usually implement enough of the sequence protocol
+    // to support this function and if not, we will only fail extraction safely.
+    let seq = unsafe {
+        if ffi::PySequence_Check(obj.as_ptr()) != 0 {
+            <PySequence as PyTryFrom>::try_from_unchecked(obj)
+        } else {
+            return Err(PyDowncastError::new(obj, "Sequence").into());
+        }
+    };
+
     let mut v = Vec::with_capacity(seq.len().unwrap_or(0) as usize);
     for item in seq.iter()? {
         v.push(item?.extract::<T>()?);