From 716f0c4e1800df5d279366369f3356732853da90 Mon Sep 17 00:00:00 2001
From: Thiago Kenji Okada <thiagokokada@gmail.com>
Date: Mon, 28 Sep 2026 09:58:40 +0100
Subject: [PATCH] nixos-rebuild-ng: handle JSONDecodeError

---
 .../nixos-rebuild-ng/src/nixos_rebuild/nix.py |  5 +-
 .../ni/nixos-rebuild-ng/src/tests/test_nix.py | 67 +++++++++----------
 2 files changed, 36 insertions(+), 36 deletions(-)

diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py
index d157839a38b7..de6d5ff8b60e 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/nix.py
@@ -511,15 +511,16 @@ def list_generations(profile: Profile) -> list[GenerationJson]:
             profile.path.parent / f"{profile.path.name}-{generation.id}-link"
         )
 
-        j: NixOSVersionJson = {}
+        j: NixOSVersionJson
         try:
             result = run_wrapper(
                 [generation_path / "sw/bin/nixos-version", "--json"],
                 capture_output=True,
             ).stdout
             j = json.loads(result)
-        except (OSError, CalledProcessError) as ex:
+        except (OSError, CalledProcessError, json.JSONDecodeError) as ex:
             logger.debug("could not get configuration revision: %s", ex)
+            j = {}
 
         return GenerationJson(
             generation=generation.id,
diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py b/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py
index 3b243678bf07..e65531090a2e 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_nix.py
@@ -590,65 +590,64 @@ def test_list_generations(
     mock_get_generations: Mock,
     tmp_path: Path,
 ) -> None:
-    mock_run.return_value = CompletedProcess(
-        args=[],
-        returncode=0,
-        stdout=json.dumps({"nixosVersion": "26.11.20260926.dirty"}),
-    )
-    assert n.list_generations(m.Profile("system", tmp_path)) == [
-        {
-            "configurationRevision": "Unknown",
-            "current": True,
-            "date": "2024-11-07 23:54:17",
-            "generation": 2,
-            "kernelVersion": "Unknown",
-            "nixosVersion": "26.11.20260926.dirty",
-            "specialisations": [],
-        },
-        {
-            "configurationRevision": "Unknown",
-            "current": False,
-            "date": "2024-11-07 23:54:17",
-            "generation": 1,
-            "kernelVersion": "Unknown",
-            "nixosVersion": "26.11.20260926.dirty",
-            "specialisations": [],
-        },
-    ]
-
+    # happy path
     mock_run.return_value = CompletedProcess(
         args=[],
         returncode=0,
         stdout=json.dumps(
             {
-                "configurationRevision": "dirty",
+                "configurationRevision": "3f0180ea99a4c8277961825ec5fca2b50a0eca75",
                 "kernelVersion": "7.2.8",
-                "nixosVersion": "26.11.20260926.dirty",
-                "specialisations": [],
+                "nixosVersion": "26.11.20260925.e94cb15",
+                "specialisations": ["foo", "bar"],
             }
         ),
     )
     assert n.list_generations(m.Profile("system", tmp_path)) == [
         {
-            "configurationRevision": "dirty",
+            "configurationRevision": "3f0180ea99a4c8277961825ec5fca2b50a0eca75",
             "current": True,
             "date": "2024-11-07 23:54:17",
             "generation": 2,
             "kernelVersion": "7.2.8",
-            "nixosVersion": "26.11.20260926.dirty",
-            "specialisations": [],
+            "nixosVersion": "26.11.20260925.e94cb15",
+            "specialisations": ["foo", "bar"],
         },
         {
-            "configurationRevision": "dirty",
+            "configurationRevision": "3f0180ea99a4c8277961825ec5fca2b50a0eca75",
             "current": False,
             "date": "2024-11-07 23:54:17",
             "generation": 1,
             "kernelVersion": "7.2.8",
-            "nixosVersion": "26.11.20260926.dirty",
+            "nixosVersion": "26.11.20260925.e94cb15",
+            "specialisations": ["foo", "bar"],
+        },
+    ]
+
+    # parsing invalid JSON
+    mock_run.return_value = CompletedProcess(args=[], returncode=0, stdout="garbage")
+    assert n.list_generations(m.Profile("system", tmp_path)) == [
+        {
+            "configurationRevision": "Unknown",
+            "current": True,
+            "date": "2024-11-07 23:54:17",
+            "generation": 2,
+            "kernelVersion": "Unknown",
+            "nixosVersion": "Unknown",
+            "specialisations": [],
+        },
+        {
+            "configurationRevision": "Unknown",
+            "current": False,
+            "date": "2024-11-07 23:54:17",
+            "generation": 1,
+            "kernelVersion": "Unknown",
+            "nixosVersion": "Unknown",
             "specialisations": [],
         },
     ]
 
+    # error calling nixos-version
     mock_run.side_effect = CalledProcessError(returncode=1, cmd=[])
     assert n.list_generations(m.Profile("system", tmp_path)) == [
         {