Error Model
Syntax vs validation errors; categories, codes, and conditions.
Internet Object defines two classes of error. Each reported error carries a stable error code (a hyphenated identifier), a human-readable message, and the position in the source where it occurred.
Syntax errors
Raised while tokenizing or parsing, before any schema is applied. They describe malformed text. Representative codes:
expecting-bracket
a {, }, [, or ] is missing
unexpected-token
a token appears where the grammar does not allow it
unexpected-positional-member
a positional value follows a keyed one in an object
unknown-member
a MemberDef uses an option the declared type does not define
string-not-closed
a quoted string has no closing quote
value-required
a value was expected (e.g. a key with no value) but none was found
invalid-datetime
a date/time literal is malformed
A conformant parser SHOULD report a malformed numeric literal (such as
0o89or0xGH) as a coded syntax error. The reference implementation currently raises an uncoded internal error for some of these — a known gap.
Validation errors
Raised while validating data against a schema. They describe values that do not satisfy the schema. Representative codes:
invalid-type
value is not of the declared type
not-a-bool / not-a-string
value is not a boolean / string for that field
invalid-range
number/date outside min/max
out-of-range / invalid-length
array/string length outside minLen/maxLen/len
invalid-min-length
string/array shorter than the minimum
invalid-choice
value is not one of choices
invalid-pattern
string does not match pattern
invalid-email / invalid-url
malformed email/URL
invalid-scale / invalid-precision
decimal scale/precision violated
value-required
a required field is missing
null-not-allowed
null given for a non-nullable field
additional-values-not-allowed
extra values without an open (*) schema
Error codes are stable; messages and exact positions may vary between implementation versions. Tooling should branch on the code, not the message.
Definition errors
A third small group arises from header references: schema-not-defined, variable-not-defined (see Error Handling in Definitions).
See Also
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