Duplicate reject reason constant value (5) in errors.go

[YoussefOuirini]

Description

I noticed that the errors.go file defines two constants with the same value 5:

rejectReasonValueIsIncorrect                  = 5
rejectReasonConditionallyRequiredFieldMissing = 5

This creates ambiguity when interpreting reject reason codes, especially in logs or downstream processing.

Reference

According to the FIX 4.4 specification (Tag 373 – SessionRejectReason):

5 = Value is incorrect (out of range) for this tag

8 = Conditionally required field missing

Therefore, it seems like rejectReasonConditionallyRequiredFieldMissing should be assigned the value 8 instead of 5.

Suggested Fix

Update the constant to:

rejectReasonConditionallyRequiredFieldMissing = 8