v0.4.0

Breaking Change: The buf::validate::Validator::Validate method no longer returns a StatusOr containing a buf::validate::Violations message, but a StatusOr containing an instance of the new buf::validate::ValidationResult class. In most cases, using the proto() method of the violation is all that needs to be done:

     auto result = validator.Validate(message).value();
     for (int i = 0; i < result.violations_size(); i++) {
-        puts(result.violation(i).GetMessage().c_str())
+        puts(result.violation(i).proto().GetMessage().c_str())
     }

buf::validate::ValidationResult itself also has a proto() method that returns the protobuf buf::validate::Violations message equivalent.

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The new buf::validate::ConstraintViolation class provides additional in-memory information about the violation which cannot be serialized to the wire:

• field_value(): Returns an absl::optional containing a buf::validate::ProtoField pointing to the value of the field failing validation, if there is a field corresponding to the violation.
• rule_value(): Returns an absl::optional containing a buf::validate::ProtoField pointing to the value of the rule failing validation, if there is a rule corresponding to the violation.

Take, for example, the following protobuf message schema:

message User {
    string email = 1 [(buf.validate.field).string.email = true];
}

If you try to validate the message User with email set to "invalid", the violation's field_value()->variant() will contain "invalid" and the rule_value()->variant() will contain true.

Some violations do not correspond directly to a field, such as a message constraint failure; in these cases, the field_value() will return absl::nullopt.

What's Changed

• Implement structured field and rule paths for violations by @jchadwick-buf in #63
• Add field and rule value to violations by @jchadwick-buf in #64

Full Changelog: v0.3.0...v0.4.0