Adding :: cast.

[fengttt]

User description

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #3335

What this PR does / why we need it:

Adding :: cast.

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PR Type

Enhancement

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Description

• Add support for PostgreSQL-style :: cast operator in MySQL dialect

• Convert :: cast syntax to standard SQL CAST() function during parsing

• Implement scanner token COLON_COLON for double colon recognition

• Add comprehensive test cases for various cast scenarios

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Diagram Walkthrough

flowchart LR
  A["Input: expr::type"] -- "Scanner tokenizes ::" --> B["COLON_COLON token"]
  B -- "Parser processes" --> C["simple_expr COLON_COLON mo_cast_type"]
  C -- "Converts to" --> D["CAST(expr AS type)"]

Loading

File Walkthrough

	Relevant files
Enhancement	scanner.go Add COLON_COLON token recognition                                                pkg/sql/parsers/dialect/mysql/scanner.go Add detection for :: operator in scanner Return new COLON_COLON token when double colon is encountered Check for second colon after first colon character +4/-0      mysql_sql.y Add :: cast operator grammar rule                                                pkg/sql/parsers/dialect/mysql/mysql_sql.y Add COLON_COLON token to grammar with right associativity Add new grammar rule for simple_expr COLON_COLON mo_cast_type Convert :: cast syntax to tree.NewCastExpr() function call +5/-0
Tests	mysql_sql_test.go Add comprehensive :: cast operator tests                                  pkg/sql/parsers/dialect/mysql/mysql_sql_test.go Add 14 test cases covering various :: cast scenarios Test cases include literals, columns, expressions, and different data types Cover edge cases like null values and complex expressions Verify conversion to standard CAST() syntax +39/-0
Miscellaneous	mysql_sql.go Update generated parser code                                                          pkg/sql/parsers/dialect/mysql/mysql_sql.go Auto-generated parser code from grammar changes Updated to handle new COLON_COLON token and cast rule +8637/-8583

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PR Compliance Guide 🔍

Below is a summary of compliance checks for this PR:

Security Compliance
⚪	Literal quote stripping Description: Test expects parser to strip quotes from string literal in comparison (right side becomes unquoted 'test'), which could cause SQL injection or semantic errors if implemented similarly in production parsing. mysql_sql_test.go [481-483] Referred Code input: "select count(*) from t where value::varchar = 'test'", output: "select count(*) from t where cast(value as varchar) = test", }, {
Ticket Compliance
🟢	🎫 #3335 🟢 Support PostgreSQL-style cast operator using the :: syntax (e.g., expr::type) in SQL. Parser should rewrite expr::type into cast(expr as type). Ensure :: works in common contexts such as literals, identifiers/columns, expressions, predicates, and with type modifiers (e.g., varchar(50)).
Codebase Duplication Compliance
⚪	Codebase context is not defined Follow the guide to enable codebase context checks.
Custom Compliance
🟢	Generic: Meaningful Naming and Self-Documenting Code Objective: Ensure all identifiers clearly express their purpose and intent, making code self-documenting Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Error Handling Objective: To prevent the leakage of sensitive system information through error messages while providing sufficient detail for internal debugging. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Logging Practices Objective: To ensure logs are useful for debugging and auditing without exposing sensitive information like PII, PHI, or cardholder data. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
⚪	Generic: Comprehensive Audit Trails Objective: To create a detailed and reliable record of critical system actions for security analysis and compliance. Status: No audit logs: The added parsing and casting features introduce new behaviors (handling :: cast) without any observable logging of critical actions, though this test-focused change may not require auditing. Referred Code input: "select '123'::int", output: "select cast(123 as int)", }, { input: "select '123'::varchar", output: "select cast(123 as varchar)", }, { input: "select a::int from t1", output: "select cast(a as int) from t1", }, { input: "select column1::timestamp from t2", output: "select cast(column1 as timestamp) from t2", }, { input: "select '2022-01-30'::date", output: "select cast(2022-01-30 as date)", }, { input: "select 123::varchar(50)", output: "select cast(123 as varchar(50))", }, { input: "select a + b::int", output: "select a + cast(b as int)", }, { ... (clipped 18 lines) Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Robust Error Handling and Edge Case Management Objective: Ensure comprehensive error handling that provides meaningful context and graceful degradation Status: Missing error handling: The new tokenization for '::' returns COLON_COLON without validating malformed sequences or providing error context, which may rely on upstream parser handling. Referred Code if s.peek(1) == ':' { s.incN(2) return COLON_COLON, "" } Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Security-First Input Validation and Data Handling Objective: Ensure all data inputs are validated, sanitized, and handled securely to prevent vulnerabilities Status: Input casting parse: The new grammar accepts 'simple_expr :: type' without visible validation of allowed types or safeguards, which may be enforced elsewhere in the type system. Referred Code | simple_expr COLON_COLON mo_cast_type { $$ = tree.NewCastExpr($1, $3) } Learn more about managing compliance generic rules or creating your own custom rules

Compliance status legend

🟢 - Fully Compliant
🟡 - Partial Compliant
🔴 - Not Compliant
⚪ - Requires Further Human Verification
🏷️ - Compliance label

[iamlinjunhong]

有语法冲突
➜ parsers git:(fengttt-greatest) ✗ make
go run github.com/matrixorigin/matrixone/pkg/sql/parsers/goyacc -o mysql_sql.go mysql_sql.y

conflicts: 14 shift/reduce
gofmt -w mysql_sql.go
rm -f y.output
go run github.com/matrixorigin/matrixone/pkg/sql/parsers/goyacc -o postgresql_sql.go postgresql_sql.y
gofmt -w postgresql_sql.go
rm -f y.output

[fengttt]

有语法冲突 ➜ parsers git:(fengttt-greatest) ✗ make go run github.com/matrixorigin/matrixone/pkg/sql/parsers/goyacc -o mysql_sql.go mysql_sql.y

conflicts: 14 shift/reduce gofmt -w mysql_sql.go rm -f y.output go run github.com/matrixorigin/matrixone/pkg/sql/parsers/goyacc -o postgresql_sql.go postgresql_sql.y gofmt -w postgresql_sql.go rm -f y.output

We will leave all shift/reduce to later work.