AVRO-4314: [csharp] Validate names against the Avro name grammar#3895
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RyanSkraba merged 3 commits intoJul 22, 2026
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Record/fixed/enum names, record field names and protocol message names were accepted verbatim when parsing, unlike enum symbols which were already validated. Because the code generator splices some of these values directly into generated C# source (for example protocol message names into a case label and field names into Get/Put switch bodies), an out-of-spec name produced malformed or unexpected generated code. Add a shared, Unicode-aware name validator (first character a letter or '_', remaining characters letters, digits or '_') and apply it to schema names, field names and message names during parsing. The rule is Unicode-aware to preserve the existing support for non-ASCII names, and namespaces are intentionally not validated because the code generator's namespace-mapping feature rewrites them to C#-specific values (such as "@return") and re-parses the schema. Add negative tests for invalid field, record and message names.
Address review feedback: - Validate record field aliases with the same rule as field names, since aliases participate in schema resolution and are names per the Avro grammar. Previously they were accepted verbatim. - Escape control characters (and quote the value) when embedding an invalid name in the SchemaParseException message, so a crafted name containing newlines or other control characters cannot produce multi-line or ambiguous error output. Add a negative test for an invalid field alias.
Address review feedback: ValidateName inspected individual UTF-16 code units, which rejected valid supplementary-plane letters and digits that are encoded as surrogate pairs. Iterate by Unicode scalar value using the char.IsLetter(string, int) / char.IsLetterOrDigit(string, int) overloads and advance past surrogate pairs. Add a test that a name containing a supplementary-plane letter (U+20000) is accepted.
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* AVRO-4314: [csharp] Validate names against the Avro name grammar Record/fixed/enum names, record field names and protocol message names were accepted verbatim when parsing, unlike enum symbols which were already validated. Because the code generator splices some of these values directly into generated C# source (for example protocol message names into a case label and field names into Get/Put switch bodies), an out-of-spec name produced malformed or unexpected generated code. Add a shared, Unicode-aware name validator (first character a letter or '_', remaining characters letters, digits or '_') and apply it to schema names, field names and message names during parsing. The rule is Unicode-aware to preserve the existing support for non-ASCII names, and namespaces are intentionally not validated because the code generator's namespace-mapping feature rewrites them to C#-specific values (such as "@return") and re-parses the schema. Add negative tests for invalid field, record and message names. * AVRO-4314: [csharp] Validate field aliases and sanitize name errors Address review feedback: - Validate record field aliases with the same rule as field names, since aliases participate in schema resolution and are names per the Avro grammar. Previously they were accepted verbatim. - Escape control characters (and quote the value) when embedding an invalid name in the SchemaParseException message, so a crafted name containing newlines or other control characters cannot produce multi-line or ambiguous error output. Add a negative test for an invalid field alias. * AVRO-4314: [csharp] Handle supplementary-plane characters in names Address review feedback: ValidateName inspected individual UTF-16 code units, which rejected valid supplementary-plane letters and digits that are encoded as surrogate pairs. Iterate by Unicode scalar value using the char.IsLetter(string, int) / char.IsLetterOrDigit(string, int) overloads and advance past surrogate pairs. Add a test that a name containing a supplementary-plane letter (U+20000) is accepted.
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Cherry-picked to branch-1.12. |
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What is the purpose of the change
Record/fixed/enum names, record field names and protocol message names were
accepted verbatim when parsing, unlike enum symbols which were already
validated. Because the code generator splices some of these values directly
into generated C# source (for example protocol message names into a
caselabel and field names into
Get/Putswitch bodies), an out-of-spec nameproduced malformed or unexpected generated code.
This change adds a shared, Unicode-aware name validator (first character a
letter or
_, remaining characters letters, digits or_) and applies it toschema names, field names and message names during parsing.
Notes:
names (e.g. the
TestRecordFieldNamescase).namespace-mapping feature rewrites them to C#-specific values (such as
@returnfor reserved words) and re-parses the schema.Verifying this change
This change added tests and can be verified as follows:
Schema/SchemaTests.cs(invalid record name, invalidfield name, and a field name attempting identifier injection) and
Protocol/ProtocolTest.cs(TestInvalidMessageName).Avro.testsuite (1526 tests) passes, includingthe AvroGen code-generation tests.
Documentation