Incorrect coerce function with duplicate capture keys in Grok patterns

[z0rc]

Migrated from elastic/logstash#7383
Created by @micoq

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Hello,

I'm not sure if it's the right repository to post this issue since the grok library is included in Logstash.

On any version of Logstash, if you have two or more fields (or named captures) in a grok pattern with the same name and using a coerce function (like "int" or "float"), this function si not applied all the time (even if the function is the same in each field).

Here is the complete issue with a quick fix : jordansissel/ruby-grok#29