LiveTable failed to format row

Expected Behavior

Live table shouldn't fail to format a row.

Current Behavior

LiveTable occasionally has issues formatting rows. We saw this first in a slack thread James Cryan in bp.list_scan.

Later seen by me in bp.adaptive_scan

This does not stop the scan from running, just breaks the terminal outputs. Originates from this exception catch.

Possible Solution

??? Possibly something to do with floats and ints?

Steps to Reproduce (for bugs)

In [3]: from bluesky.plans import adaptive_scan
   ...: from ophyd.sim import motor, det
   ...:
   ...: RE(adaptive_scan([det], 'det', motor,
   ...:                  start=-15,
   ...:                  stop=10,
   ...:                  min_step=0.01,
   ...:                  max_step=5.,
   ...:                  target_delta=.05,
   ...:                  backstep=True))


Transient Scan ID: 2     Time: 2022-04-19 13:33:54
Persistent Unique Scan ID: '22ecca5f-4be2-4645-ad7c-f557d3a4db61'
New stream: 'primary'
+-----------+------------+------------+------------+
|   seq_num |       time |      motor |        det |
+-----------+------------+------------+------------+
|         1 | 13:33:54.2 |        -15 |   1.39e-49 |
 failed to format row
 failed to format row
 failed to format row

RE(bp.list_scan([daq], photon_energy, list1))

(resolved by defining the list as floats, not int)

Context

Your Environment

pcds-5.3.1

Start with the exception catch in bluesky/callbacks/core.py at the linked lines, then reproduce the failure using adaptive_scan and list_scan as shown. Compare the row values that trigger the error, including the reported int-versus-float difference. Done means LiveTable formats these rows without printing “failed to format row” while the scan continues normally.