Fix enum prefix parsing for Python

[welshm]

Enums with common prefixes are not generated properly in Python

EnumWithCommonPrefix:
      type: string
      example: VAL_2
      enum:
        - VAL_1
        - VAL_2
        - VAL_3
      default: VAL_2

This would result in the default value being ENUM_2 - while the generated enum values are VAL_1 VAL_2 and VAL_3

This is because buildEnumVars in DefaultCodegen checks for common prefixes

 protected List<Map<String, Object>> buildEnumVars(List<Object> values, String dataType) {
        List<Map<String, Object>> enumVars = new ArrayList<>();
        int truncateIdx = isRemoveEnumValuePrefix()
                ? findCommonPrefixOfVars(values).length()
                : 0;
...

which causes the incorrect name to be used for the default value where the name is constructed directly from the enumVar.

The correct long term fix is to check isRemoveEnumValuePrefix() when constructing the enum variable names in Python as well (see public String toEnumVariableName(String name, String datatype) inside AbstractPythonCodegen) - however this also requires that many of the mustache files be updated to properly support de/serialization from JSON into the enum types - which Flask (and others) don't currently support.

This is a smaller solution to fix the bug until the longer implementation can be completed.

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[welshm]

Tagging Python technical committee

@cbornet @tomplus @krjakbrjak @fa0311 @multani

@wing328

[wing328]

did you try setting the option removeEnumValuePrefix to false? e.g. --additional-properties removeEnumValuePrefix=false

ref; #5166 (comment)

[welshm]

did you try setting the option removeEnumValuePrefix to false? e.g. --additional-properties removeEnumValuePrefix=false

ref; #5166 (comment)

So that will work, but having it set to true leads to broken output. I can drop this PR if you don't think it adds value - but I think that forcing working behaviour is more correct.

The correct long term fix is to check isRemoveEnumValuePrefix() when constructing the enum variable names in Python as well (see public String toEnumVariableName(String name, String datatype) inside AbstractPythonCodegen) - however this also requires that many of the mustache files be updated to properly support de/serialization from JSON into the enum types - which Flask (and others) don't currently support.

Proper support for that value I do think is the long term fix, but likely requires updating all python generators.