fix(siri): add venv to the siril installation

Reviewed-on: #76

flake.lock

@@ -8,11 +8,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1787559586,
+        "lastModified": 1788450739,
-        "narHash": "sha256-onL0VLf9vPllmT0H/OlURIU5r5t5WIEl7t4tVNKT0Nw=",
+        "narHash": "sha256-glZLQlzIn1fXH6PazR2iUmTo7kzzyYSshrWhLS9TqCU=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "9d0d87172c374f89da73c1cfe6d81ae62feac1f1",
+        "rev": "31729ca8cbdb4fa927b34e5f4353e6a83f39e993",
         "type": "github"
       },
       "original": {
@@ -28,11 +28,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1787797243,
+        "lastModified": 1789430117,
-        "narHash": "sha256-8+Q7NOB7RPajRjA4pbCDLzqH+MTjnG9x6LUPLfL2joA=",
+        "narHash": "sha256-t+U1mijItLJ64xZOifpfQ17kpAL73nU7pDI48ScacVc=",
         "owner": "nix-community",
         "repo": "home-manager",
-        "rev": "99c9ec63390f1d8c14d95d9e8b17cc29cfbd4e11",
+        "rev": "cda90fd8838825c689fde9d3f3b4e937937790df",
         "type": "github"
       },
       "original": {
@@ -43,11 +43,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1787900134,
+        "lastModified": 1789286504,
-        "narHash": "sha256-VYXO0XZlgj06dxJZRhrD3WoSsvq/c7+/Akyoa22pefw=",
+        "narHash": "sha256-eiEK7cKZORNEvX0GeF3RtNEF/JXhgf2RqSp3230q13E=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "83199d0d373dd3ac2b9a1996b1d0263f76ab7a4c",
+        "rev": "ef34387ddd751e1ab8857adf4676492d32eb24ec",
         "type": "github"
       },
       "original": {
@@ -66,11 +66,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1787862710,
+        "lastModified": 1789344271,
-        "narHash": "sha256-dL1Tv7LekaTWUJxHRckjbupWczDdc3QOgRuVCM+WAvQ=",
+        "narHash": "sha256-ezmg5oQSZWYdmomx6K1J+/6w7dRc7bquDMggc8eAE28=",
         "owner": "nix-community",
         "repo": "nixvim",
-        "rev": "8c096abcf376137527c134da4ee210332b08ccc0",
+        "rev": "afcfb8c1dc075881bbaa6fa5745aebbdb179f8b8",
         "type": "github"
       },
       "original": {
@@ -86,11 +86,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1788099672,
+        "lastModified": 1789436433,
-        "narHash": "sha256-t4Rw5OeULK/WA2Jh9ja615sCs2AmvahkAUx/ymdf2YQ=",
+        "narHash": "sha256-/Dy5P/7nCIss+uAhdF+8I59ww5WQUF4EBs1QJCB1aec=",
         "owner": "noctalia-dev",
         "repo": "noctalia-shell",
-        "rev": "d891007c022a3a1d4484495fe8b350a00deafae9",
+        "rev": "e4eb0ff97743c1d07d0f5a0d5770b277b6485b03",
         "type": "github"
       },
       "original": {

modules/nixos/astro.nix

@@ -15,7 +15,15 @@ let
     # on PATH. nixpkgs only *propagates* python3 from the siril derivation (it
     # isn't on the runtime PATH), so without the --prefix PATH below the GUI
     # fails with "Python not found in system PATH" and never creates
-    # ~/.local/share/siril/venv. We add the same interpreter siril references.
+    # ~/.local/share/siril/venv.
+    #
+    # We deliberately do NOT put ${pkgs.python3}/bin on PATH directly: `venv`
+    # symlinks bin/python3 to whatever sys.executable was, so the venv would
+    # hard-link a /nix/store hash that gets garbage-collected after the next
+    # python bump, leaving a dangling symlink ("Error finding venv python
+    # path, unable to spawn python"). Instead we go through the stable
+    # /etc/siril/bin/python3 symlink (see environment.etc below), which NixOS
+    # re-points at the current python on every rebuild.
     #
     # The VeraLux PyQt6 wheel ships only the built-in Windows/Fusion styles, so
     # the global QT_STYLE_OVERRIDE=adwaita-dark (inherited from the session) is
@@ -26,7 +34,7 @@ let
     # ignored again (harmless warning + Fusion fallback, no loss of function).
     postBuild = ''
       wrapProgram $out/bin/siril \
-        --prefix PATH : ${lib.makeBinPath [ pkgs.python3 ]} \
+        --prefix PATH : /etc/siril/bin \
         --prefix QT_PLUGIN_PATH : ${pkgs.adwaita-qt6}/lib/qt-6/plugins \
         --prefix LD_LIBRARY_PATH : ${lib.makeLibraryPath (with pkgs; [
           stdenv.cc.cc.lib   # libstdc++ / libgcc_s / libgomp  (numpy etc.)
@@ -62,6 +70,10 @@ in
     sirilWithPlugins
   ];
 
+  # Stable, GC-safe interpreter path for Siril's venv (see sirilWithPlugins).
+  # Same python as siril itself propagates, so sirilpy's ABI matches.
+  environment.etc."siril/bin/python3".source = "${pkgs.python3}/bin/python3";
+
   # StarNet++ has no nixpkgs package. Download the StarNet v2 ORT CLI build
   # (starnet2_linux_*_ORT_x64_cli) from https://www.starnetastro.com/download/
   # and unzip it to ~/.local/share/siril/starnet/. Then in Siril set