Purge check: fail when bd_pressure does not answer, add override

A bd_pressure that does not answer used to be reported as "pressure
skipped" and the purge passed unchecked. It now fails the check, so in
enforce mode the printer pauses (and a resume purge stays paused).
PURGE_CHECK_IGNORE_SENSOR lets purges pass without the sensor until the
print ends; _PRINT_CLEANUP clears it so the next print checks again.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

macros/afc/purge_check.cfg

@@ -32,7 +32,10 @@
 [bdwidth_status]
 sensor: fila_width_0
 
-# Remove this section if bdpressure_check.py is not installed
+# Remove this section if bdpressure_check.py is not installed. With it
+# installed, a bd_pressure that does not answer (stock firmware, hung or
+# unplugged sensor) fails the check, so in enforce mode every purge pauses;
+# PURGE_CHECK_IGNORE_SENSOR lets the current print finish without it.
 [bdpressure_check]
 sensor: bd_pa
 
@@ -50,6 +53,7 @@ variable_bdwidth_warmup_ms: 15000
 variable_start_counts: 0
 variable_start_e: 0.0
 variable_last_failed: False    # last check failed in enforce mode (read by _RESUME_PURGE_VERIFY)
+variable_ignore_missing_sensor: False  # set by PURGE_CHECK_IGNORE_SENSOR, cleared at print end
 gcode:
 
 [gcode_macro BLOBIFIER_CHECKED]
@@ -144,8 +148,15 @@ gcode:
             {% if p.longest_ms < cfg.pressure_min_ms %}
                 {% set _ = failed.append("no sustained nozzle pressure") %}
             {% endif %}
+        {% elif 'bdpressure_check' in printer %}
+            {% if cfg.ignore_missing_sensor %}
+                {% set press = "pressure skipped: bd_pressure not answering (ignored, PURGE_CHECK_IGNORE_SENSOR)" %}
+            {% else %}
+                {% set press = "bd_pressure not answering" %}
+                {% set _ = failed.append("bd_pressure not answering (power-cycle the sensor, or PURGE_CHECK_IGNORE_SENSOR to finish this print without the check)") %}
+            {% endif %}
         {% else %}
-            {% set press = "pressure skipped (no check firmware)" %}
+            {% set press = "pressure skipped (no bdpressure_check)" %}
         {% endif %}
         {% set checked = motion_on or 'bdpressure_check' in printer and printer.bdpressure_check.available %}
         {% set verdict = 'FAIL: ' ~ failed|join(', ') if failed else ('OK' if checked else 'NOTHING CHECKED') %}
@@ -156,3 +167,14 @@ gcode:
             PAUSE                       ; no effect while already paused (resume purge): see _RESUME_PURGE_VERIFY
         {% endif %}
     {% endif %}
+
+[gcode_macro PURGE_CHECK_IGNORE_SENSOR]
+description: Let purges pass without bd_pressure until the print ends (ENABLE=0 to undo)
+gcode:
+    {% if params.ENABLE|default(1)|int %}
+        SET_GCODE_VARIABLE MACRO=_PURGE_CHECK_CFG VARIABLE=ignore_missing_sensor VALUE=True
+        RESPOND MSG="PURGE_CHECK: an unavailable bd_pressure is ignored until the print ends (purges are not checked for pressure then)"
+    {% else %}
+        SET_GCODE_VARIABLE MACRO=_PURGE_CHECK_CFG VARIABLE=ignore_missing_sensor VALUE=False
+        RESPOND MSG="PURGE_CHECK: an unavailable bd_pressure fails the check again"
+    {% endif %}

macros/print/print_start_end.cfg

@@ -257,6 +257,9 @@ gcode:
     M221 S100
     BED_MESH_CLEAR
     SET_SKEW CLEAR=1
+    {% if 'gcode_macro _PURGE_CHECK_CFG' in printer %}
+    SET_GCODE_VARIABLE MACRO=_PURGE_CHECK_CFG VARIABLE=ignore_missing_sensor VALUE=False
+    {% endif %}
 
 # Retract/unretract that is remembered across prints and restarts.
 # Klipper's G10 only retracts once until a G11, and nothing sends G11 here,