From 83a2b9ccb07d5396402d6f43d7ba9322f686afe8 Mon Sep 17 00:00:00 2001
From: Gertjan Bisschop <gertjanbisschop@gmail.com>
Date: Tue, 8 Aug 2023 12:54:48 +0100
Subject: [PATCH] raise error when recording migrants

---
 msprime/ancestry.py  | 12 ++++++++----
 tests/test_models.py | 27 +++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/msprime/ancestry.py b/msprime/ancestry.py
index b44dd2995..e62b66a4f 100644
--- a/msprime/ancestry.py
+++ b/msprime/ancestry.py
@@ -866,18 +866,22 @@ def _parse_sim_ancestry(
                     " additional_nodes."
                 )
 
-        if is_dtwf:
-            if additional_nodes.value & NodeType.MIGRANT.value:
+        if additional_nodes.value & NodeType.MIGRANT.value:
+            if is_dtwf:
                 raise ValueError(
                     "Recording MIGRANT nodes is currently not supported in"
                     " DTWF simulation."
                 )
-        if is_pedigree:
-            if additional_nodes.value & NodeType.MIGRANT.value:
+            if is_pedigree:
                 raise ValueError(
                     "Recording MIGRANT nodes is not supported in "
                     "FixedPedigree simulation."
                 )
+            if any(isinstance(model, SweepGenicSelection) for model in models):
+                raise ValueError(
+                    "Recording MIGRANT nodes is not supported in "
+                    "SweepGenicSelection simulation."
+                )
 
     record_migrations = core._parse_flag(record_migrations, default=False)
 
diff --git a/tests/test_models.py b/tests/test_models.py
index cf5b0933c..56bf673b1 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -962,3 +962,30 @@ def test_lots_of_sweeps(self):
             random_seed=2,
         )
         assert all(tree.num_roots == 1 for tree in ts.trees())
+
+    def test_sweep_migration_event(self):
+        models = [
+            msprime.StandardCoalescent(duration=0.01),
+            msprime.SweepGenicSelection(
+                position=5,
+                start_frequency=0.69,
+                end_frequency=0.7,
+                s=0.1,
+                dt=1e-6,
+            ),
+        ]
+        with pytest.raises(
+            ValueError,
+            match="Recording MIGRANT nodes is not supported in "
+            "SweepGenicSelection simulation.",
+        ):
+            msprime.sim_ancestry(
+                3,
+                population_size=1000,
+                sequence_length=10,
+                recombination_rate=0.2,
+                model=models,
+                random_seed=2,
+                coalescing_segments_only=False,
+                additional_nodes=msprime.NodeType.MIGRANT,
+            )