`mip_convert` failures when using a .pp ancil that contains time stamps

[mo-gill]

If a pp ancil that contains time stamps is used in a mip convert run (in this case trying to process slthick_ti-sl-hxy-lnd using the ancil called "test_input_land_fx_u-dk469.pp" from the functional test for the same variable, this error is thrown:

No data available for "1850"; please check run_bounds
Traceback (most recent call last):
  File "CDDS/mip_convert/mip_convert/request.py", line 124, in convert
    produce_mip_requested_variable(variable_name, stream_id, substream, mip_table, user_config,
  File "CDDS/mip_convert/mip_convert/requested_variables.py", line 140, in produce_mip_requested_variable
    for time_slice in variable.slices_over(period):
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File CDDS/mip_convert/mip_convert/new_variable.py", line 234, in slices_over
    sliced_input_variables = self._slice_input_variables(date_time, date_times)
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "CDDS/mip_convert/mip_convert/new_variable.py", line 860, in _slice_input_variables
    raise RuntimeError('No data available for "{}"; please check run_bounds'.format(date_time_str))
RuntimeError: No data available for "1850"; please check run_bounds

Here is a look at the data for that ancil, showing that it has start dates:

ppfp test_input_land_fx_u-dk469.pp 
/ppfp.py: input: test_input_land_fx_u-dk469.pp
     DATE    01/07/2026      TIME 10:58:27

       START          END                                                      
   Y M D h m    Y M D h m   PROC STASH   EXP     LREC LBLEV       LEV     HLEV 
225701010000 000000000000      0     9 AAAAA    27648     0      0.05      0.0 
225701010000 000000000000      0     9 AAAAA    27648     0      0.22      0.0 
225701010000 000000000000      0     9 AAAAA    27648     0      0.68      0.0 
225701010000 000000000000      0     9 AAAAA    27648     0      2.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
225701010000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 

For the purposes of processing this variable, i modified this ancil to zero out the start dates e.g.:

      START          END                                                      
   Y M D h m    Y M D h m   PROC STASH   EXP     LREC LBLEV       LEV     HLEV 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0   216 AAAAA    27648     0      0.00      0.0 
000000000000 000000000000      0     9 AAAAA    27648     0      0.05      0.0 
000000000000 000000000000      0     9 AAAAA    27648     0      0.22      0.0 

This allows the variable to be processed.

What i found a little odd is that the functional test does pass when using the pp ancil containing START times.

However, i think it's to do with the fact the request used for that functional test has run_bounds that happen to match those in the ancil e.g. 'run_bounds': '2257-01-01T00:00:00 2257-02-01T00:00:00',

I'm assuming that ancils shouldn't be containing time stamps like the one in the functional test.

This issue is to add some kind of handling of pp ancil data if it contains time stamps like this. Though this is low priority, as i think such ancils we accept should have no time stamps like this (correct me if im wrong).

This bug was discovered during issue #918