From 9ebb216f58d029f66c983ab732cc9f0d1429c688 Mon Sep 17 00:00:00 2001
From: Rob Nagler <5495179+robnagler@users.noreply.github.com>
Date: Sat, 11 Apr 2026 23:10:26 +0000
Subject: [PATCH 1/2] Fix #640 fconf list of list should not merge

---
 pykern/fconf.py                 | 3 ++-
 tests/fconf_data/1.in/1.yml     | 1 +
 tests/fconf_data/1.out/res.json | 5 +++++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/pykern/fconf.py b/pykern/fconf.py
index b89ea901..89fea058 100644
--- a/pykern/fconf.py
+++ b/pykern/fconf.py
@@ -457,7 +457,8 @@ def _list(self, new, base):
             # lists don't have base values
             with self._xpath(f"[{i}]"):
                 x = self._do(e, None)
-            if isinstance(x, list):
+            # if list of lists, just append. If expression returns list, then extend
+            if not isinstance(e, list) and isinstance(x, list):
                 res.extend(x)
             else:
                 res.append(x)
diff --git a/tests/fconf_data/1.in/1.yml b/tests/fconf_data/1.in/1.yml
index 10aeea7b..05ca88d5 100644
--- a/tests/fconf_data/1.in/1.yml
+++ b/tests/fconf_data/1.in/1.yml
@@ -29,6 +29,7 @@ one:
   more_items(inside()):
   list:
     - r0
+    - [a, b, c]
     - red()
   mixed: mymap(host, range(3, 5))
   all_hosts: map(host, ${top.hosts})
diff --git a/tests/fconf_data/1.out/res.json b/tests/fconf_data/1.out/res.json
index 96cee0db..05b69cc6 100644
--- a/tests/fconf_data/1.out/res.json
+++ b/tests/fconf_data/1.out/res.json
@@ -56,6 +56,11 @@
         ],
         "list": [
             "r0",
+            [
+                "a",
+                "b",
+                "c"
+            ],
             "r1",
             "r2"
         ],

From ad5e8ea41ac4288c25130a89a7f10a9d08eb9fd1 Mon Sep 17 00:00:00 2001
From: Rob Nagler <5495179+robnagler@users.noreply.github.com>
Date: Sat, 11 Apr 2026 23:32:56 +0000
Subject: [PATCH 2/2] upgrade to 3.13

---
 .readthedocs.yml                                     | 2 +-
 pykern/package_data/projex/dot-readthedocs.yml.jinja | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.readthedocs.yml b/.readthedocs.yml
index a4206602..fa10316d 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -4,7 +4,7 @@ version: 2
 build:
   os: ubuntu-22.04
   tools:
-    python: "3.9"
+    python: "3.13"
   jobs:
     pre_build:
      - curl https://radia.run | bash -s readthedocs
diff --git a/pykern/package_data/projex/dot-readthedocs.yml.jinja b/pykern/package_data/projex/dot-readthedocs.yml.jinja
index a4206602..fa10316d 100644
--- a/pykern/package_data/projex/dot-readthedocs.yml.jinja
+++ b/pykern/package_data/projex/dot-readthedocs.yml.jinja
@@ -4,7 +4,7 @@ version: 2
 build:
   os: ubuntu-22.04
   tools:
-    python: "3.9"
+    python: "3.13"
   jobs:
     pre_build:
      - curl https://radia.run | bash -s readthedocs