Fix import error [ijson]

[naik-aakash]

Closes #702

Changes

1. Enable MPVaspLobsterMaker only if lobsterpy and ijson are installed i.e atomate2 is installed using atomate2[lobster] dependencies
2. Add warning message for the same incase MPVaspLobsterMaker is disabled.

Below is the snapshot of warning printed when MPVaspLobsterMaker is disabled.

[naik-aakash]

Hi @jmmshn, I hope this addresses the problem now.

@JaGeo , just tagging you here incase you have any more suggestions or comments on this change.

[codecov]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (aaa08c0) 76.21% compared to head (62ae659) 76.19%.
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #708      +/-   ##
==========================================
- Coverage   76.21%   76.19%   -0.03%     
==========================================
  Files          87       87              
  Lines        7165     7178      +13     
  Branches     1057     1057              
==========================================
+ Hits         5461     5469       +8     
- Misses       1383     1388       +5     
  Partials      321      321              

Files	Coverage Δ
src/atomate2/vasp/flows/mp.py	90.32% <100.00%> (+0.32%)	⬆️
src/atomate2/lobster/schemas.py	91.13% <66.66%> (-0.21%)	⬇️
src/atomate2/vasp/flows/lobster.py	83.92% <60.00%> (-5.21%)	⬇️

[utf]

Hi @naik-aakash, thanks for this PR.

I think we could handle this differently. Ideally, the warning would be raised if you are actually trying to use the MPVaspLobsterMaker. Instead, this warning gets raised even if you just import the MP module.

The typical way of doing this is using the monty requires decorator. E.g., see here:

atomate2/src/atomate2/lobster/schemas.py

Lines 523 to 525 in 19849ff

	@classmethod
	@requires(Analysis, "lobsterpy must be installed to create an CalcQualitySummary.")
	def from_directory(

My suggestion would be:

1. Replace the ijson import in with:

try:
    import ijson
except ImportError:
    ijson = None

2. Add the requires decorator onto the function that needs ijson.

[naik-aakash]

Thanks @utf, for the suggestion, I will make the required changes.

[naik-aakash]

Hi @utf , I have now made the changes and this PR could be merged if you think this is fine.

[utf]

Looks great, thank you!