ConstrainedFloat schema: differences between IEEE floats and json

[vdwees]

Change Summary

Modify constraints on ConstrainedFloat schema to account for differences between IEEE floats and json

Transformations applied:

• remove field exclusiveMinimum if it is equal to -math.inf
• remove field minimum if it is equal to -math.inf
• remove field exclusiveMaximum if it is equal to math.inf
• remove field maximum if it is equal to math.inf

Related issue number

#1417

Checklist

• Unit tests for the changes exist
• Tests pass on CI and coverage remains at 100%
• Documentation reflects the changes where applicable
• changes/<pull request or issue id>-<github username>.md file added describing change
  (see changes/README.md for details)

[codecov]

Codecov Report

Merging #1422 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #1422   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           21        21           
  Lines         3741      3759   +18     
  Branches       740       747    +7     
=========================================
+ Hits          3741      3759   +18     

Impacted Files	Coverage Δ
pydantic/schema.py	100.00% <100.00%> (ø)
pydantic/types.py	100.00% <100.00%> (ø)
pydantic/utils.py	100.00% <0.00%> (ø)

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[samuelcolvin]

good point from @chris-allnutt, we should use the JSON values Infinity and -Infinity.

[vdwees]

good point from @chris-allnutt, we should use the JSON values Infinity and -Infinity.

Its tricky because NaN, Infinity, and -Infinity are not valid JSON, but a lot of python json libs include them.

[samuelcolvin]

The acid test for me (both semantically and practically) is: what happens in js with JSON.parse(...)? I'd suggest we follow that.

(I'm on my phone atm., so don't actually know the answer)

[vdwees]

Here is the javascript JSON behaviour (tested in Firefox, but this is a pretty fundamental language feature):

>>JSON.stringify({var:Infinity})
"{\"var\":null}"
>>JSON.parse("{\"var\":Infinity}")
SyntaxError: JSON.parse: unexpected character at line 1 column 8 of the JSON data

[samuelcolvin]

otherwise LGTM.

[samuelcolvin]

thanks a lot.