Improve compatibility by ignoring invalid values instead of failing

[atschabu]

We keep running into compatibility issues, as various (test) environments have Locations and Tariffs with invalid information. This could range from completely wrong entries (country codes with more than 2 digits), easily ignorable issues (invalid enum value in optional field) to fixable issues (lat/lng with too many decimals)

Not only will this cause PUT/PATCH requests to fail, but also blocks paginated GET calls, as a single wrong field causes the entire call to be marked as invalid.

To improve compatibility, I'd suggest the following:

• All deserialisers use Partials -> this allows filtering out bad entries from a list
• All optional enums have a @JsonEnumDefaultValue UNKNOWN entry combined with DeserializationFeature#READ_UNKNOWN_ENUM_VALUES_USING_DEFAULT_VALUE
• Configurable validation that allows fixing values and ignoring UNKNOWN values instead of error

The execution chain for clients on GET would be

• Deserialize Partial
• Validate
  • optionally fixes issues
  • optionally ignores UNKNOWN and sets it to null
  • per entry, in case of list, and allows to filter invalid entries
• convert to non-partial (can be code generated mapper)

The execution chain for server on PUT/PATCH/POST would be

• transportServer handler
  • deserializes partial
• service
  • validates with optional overrides and fixes
  • converts to non-partial

All these changes should be possible entirely within this lib, without affecting existing repo interfaces. Validation could be configured by either providing a Validator instance (instead of current static calls) or providing configuration in coroutine context

[lilgallon]

I totally agree with you -> #161