Node position silently reset to (0, 0) when any coordinate is zero — all([...]) treats 0.0 as missing on XML load

[lamestllama]

When a scenario/session XML is loaded, any node whose has a coordinate of exactly 0 has its entire position discarded and falls back to the Position default of (0.0, 0.0). The node therefore jumps to the top-left corner of the canvas instead of where the file says.

The trigger is a single coordinate being 0:

x="0" or y="0" drops the Cartesian position.
lat="0" (equator), lon="0" (prime meridian), or alt="0" (sea level) drops the geo position.
Because exporters very commonly write alt="0.0", the geo branch is effectively always skipped, and a node sitting on the canvas top/left edge (x=0 or y=0) is the common real-world trigger for the Cartesian branch.

Version: CORE 9.2.0

ROOT CAUSE

daemon/core/xml/corexml.py guards every position assignment with all([...]), which uses Python truthiness — and 0.0 is falsy. So a legitimate zero coordinate is indistinguishable from a missing one. get_float() already returns None for a genuinely-missing attribute, so the intent ("only set if present") should be an explicit "is not None" check, not all([...]).

read_device (around line 660):

x = get_float(position_element, "x")
y = get_float(position_element, "y")
if all([x, y]): # all([1488.0, 0.0]) -> False, so set() is skipped
position.set(x, y)
lat = get_float(position_element, "lat")
lon = get_float(position_element, "lon")
alt = get_float(position_element, "alt")
if all([lat, lon, alt]): # alt is typically 0.0 -> always False
position.set_geo(lon, lat, alt)
Position defaults to the origin (daemon/core/nodes/base.py):

class Position:
x: float = 0.0
y: float = 0.0
z: float = 0.0
So when the guard is False, position.set(...) is never called and the node keeps (0.0, 0.0).

The same pattern appears 6 times across 3 methods:

read_session_origin: x/y guard ~line 584, lat/lon/alt guard ~line 574
read_device: x/y guard ~line 701, lat/lon/alt guard ~line 706
read_network: x/y guard ~line 728, lat/lon/alt guard ~line 733
MINIMAL DEMONSTRATION

The whole bug in two lines:

x, y = 1488.0, 0.0 # a node on the canvas top edge
all([x, y])
False # -> position.set(x, y) is skipped -> node stays at Position() == (0, 0)
STEPS TO REPRODUCE (GUI)

Open the GUI and place a router.
Set its position to something with a zero coordinate, e.g. x=500, y=0 (drag it to the very top edge, or edit the saved XML so ).
Save the session to XML.
Open that XML (core-gui -s session.xml, or File -> Open).
Expected: the node appears at (500, 0).
Actual: the node appears at (0, 0) (top-left corner). Any other node in the file with a zero x or y collapses to the same corner.

SUGGESTED FIX

Replace the truthiness checks with explicit None checks in all three methods:

•    if all([x, y]):
  

•    if x is not None and y is not None:
         position.set(x, y)
  

•    if all([lat, lon, alt]):
  

•    if lat is not None and lon is not None and alt is not None:
         position.set_geo(lon, lat, alt)
  

get_float() returns None for a missing attribute, so this preserves the "only set when present" intent while accepting legitimate zero coordinates. The same change applies at the read_session_origin, read_device, and read_network sites.

[bharnden]

Thanks for the input, at the time some of these pain points were taken in due to inputs received from gRPC and at the time removed support for optional.

That has been added back and some adjustments should be made in relation to that, appreciate it.