Depend on python3-aprslib; stop masking the import failure

aprscot 8.2.0-1 cannot start at all as packaged. On a fresh AryaOS box:

  AttributeError: module 'aprscot' has no attribute 'KISSWorker'
  at functions.py:49 in create_tasks

The real cause is two problems stacked.

MISSING DEPENDENCY. classes.py imports aprslib.parsing, and setup.cfg
correctly lists aprslib in install_requires, but the generated deb
Depends on only "pytak, python3-aiohttp" -- stdeb did not translate
aprslib into python3-aprslib. python3-aprslib IS in Debian (0.7.2-2), so
the fix is just to name it in stdeb.cfg.

MASKED FAILURE. __init__.py wrapped every import in

  except ImportError as exc:
      warnings.warn(f"COMPAT: CI. Ignoring Exception {str(exc)}")

a leftover py3.6 CI shim. It swallowed "No module named 'aprslib'", left
the module loaded but exporting nothing, and turned a clear import error
into an AttributeError thrown much later and much further away. Every
path was affected -- KISS, the APRS-IS internet feed, and SensorWorker --
so no configuration of aprscot could have worked.

Constants import unconditionally (no third-party deps), and the class and
function imports are now allowed to raise. A missing dependency should
stop the process at import with the name of what is missing.

Verified: with aprslib present all three workers and create_tasks are
exported; with aprslib hidden the import now fails loudly with "No module
named 'aprslib'" instead of silently degrading.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0197da7dhvcPoHxYKamrYqyM

Author: gba

aprscot/__init__.py

@@ -20,30 +20,26 @@
 
 __version__ = "8.2.0"
 
-# COMPAT: CI compat (was py 3.6)
-try:
-    from .constants import (  # NOQA
-        DEFAULT_APRSIS_PORT,
-        DEFAULT_COT_TYPE,
-        DEFAULT_COT_STALE,
-        DEFAULT_APRSIS_HOST,
-        DEFAULT_APRSIS_CALLSIGN,
-        DEFAULT_APRSIS_PASSCODE,
-        DEFAULT_APRSIS_FILTER,
-        DEFAULT_KISS_PORT,
-        DEFAULT_SENSOR_KEEPALIVE_PERIOD,
-        DEFAULT_SENSOR_LAT,
-        DEFAULT_SENSOR_LON,
-        DEFAULT_SENSOR_HAE,
-        DEFAULT_SENSOR_ID,
-        DEFAULT_SENSOR_COT_TYPE,
-        DEFAULT_SENSOR_PAYLOAD_TYPE,
-    )
+# Constants are safe to import with no third-party dependencies, so they are
+# imported unconditionally and a genuine problem here is allowed to raise.
+from .constants import (  # NOQA
+    DEFAULT_APRSIS_PORT,
+    DEFAULT_COT_TYPE,
+    DEFAULT_COT_STALE,
+    DEFAULT_APRSIS_HOST,
+    DEFAULT_APRSIS_CALLSIGN,
+    DEFAULT_APRSIS_PASSCODE,
+    DEFAULT_APRSIS_FILTER,
+    DEFAULT_KISS_PORT,
+    DEFAULT_SENSOR_KEEPALIVE_PERIOD,
+    DEFAULT_SENSOR_LAT,
+    DEFAULT_SENSOR_LON,
+    DEFAULT_SENSOR_HAE,
+    DEFAULT_SENSOR_ID,
+    DEFAULT_SENSOR_COT_TYPE,
+    DEFAULT_SENSOR_PAYLOAD_TYPE,
+)
 
-    from .functions import aprs_to_cot, create_tasks, gen_sensor_cot  # NOQA
+from .functions import aprs_to_cot, create_tasks, gen_sensor_cot  # NOQA
 
-    from .classes import APRSWorker, KISSWorker, SensorWorker  # NOQA
-except ImportError as exc:
-    import warnings
-
-    warnings.warn(f"COMPAT: CI. Ignoring Exception {str(exc)}")
+from .classes import APRSWorker, KISSWorker, SensorWorker  # NOQA

stdeb.cfg

@@ -1,4 +1,4 @@
 [DEFAULT]
 Package3: aprscot
 Replaces3: python3-aprscot
-Depends3: pytak, python3-aiohttp
+Depends3: pytak, python3-aiohttp, python3-aprslib