Remove the coerce option on numeric fields.

[jpountz]

I don't like the fact that the coerce option combines a useful feature: the ability to convert strings to a number (which we are supposed to do in most APIs anyway) with a dangerous feature: the truncation (it does not even round) of floating-point numbers when indexed as a byte/short/integer/long.

I think we should remove this option, accept a string in all cases and require users to use an ingest processor if they want to ignore the decimal part of their floating-point numbers. Note that eg. "1.0" would still be accepted in an integer field since its decimal part is equal to zero.

[jpountz]

We had a brief discussion about it in the search meeting and there was consensus that enabling truncation by default can be trappy. We discussed the following alternatives:

• keep the coerce option but make it only about accepting strings
• add an option that tells the field what to do if there is a decimal part (truncate/floor/ceil/round)

We should also try to gather feedback about use-cases for truncating, if any, and what users should migrate to instead (the convert processor?).

[jimczi]

Discussed in Fix it Friday and we agreed that we should keep the coerce option and make it only about accepting strings. The automatic truncation is not a good option and should be replaced with an ingest processor that does the right thing (floor/ceil/round).

[nablyy]

hi I'd like to look into this as my first PR.
is there a good place to start looking in the code to address this?

[jpountz]

@nablyy You should look at NumberFieldMapper, and try to disallow floating-point numbers that have a decimal part on integer types and 7.x indices.

[liketic]

@nablyy If you're not working on this, can I take this?

[nablyy]

@liketic If you want, take this.