Extended Rules

Relevant source files

• .github/instructions/go.instructions.md
• DEVELOPING.md
• README.md
• RULES_DESCRIPTIONS.md
• config/config.go
• config/config_test.go
• lint/filefilter.go
• logging/logger.go
• logging/logger_test.go
• revive.toml
• rule/confusing_naming.go
• rule/datarace.go
• rule/error_strings_test.go
• rule/string_format.go
• rule/unchecked_type_assertion.go
• testdata/confusing_naming1.go
• tools/pinversion.go

Purpose and Scope

This page documents the extended rules available in revive beyond the 23 default golint-compatible rules. These extended rules provide additional linting capabilities for code quality, complexity analysis, correctness checking, and style enforcement. The extended rule set includes approximately 79 additional rules that can detect issues ranging from potential race conditions to style inconsistencies.

For information about the default golint-compatible rules, see Default Rules. For details on rule architecture and interfaces, see Rule Architecture and Interfaces. For guidance on creating your own rules, see Creating Custom Rules.

Rule Classification

Extended rules in revive are organized into a two-tier system: default rules that maintain golint compatibility, and additional rules that extend the linter's capabilities.

Sources: config/config.go16-122

Extended Rule Categories

Extended rules are functionally organized into distinct categories based on their analysis focus and purpose.

Sources: config/config.go42-122 README.md494-597

Comprehensive Rule Listing

The following table categorizes all extended rules by their primary function:

Category	Rules	Config	Typed
Complexity & Size Limits	cyclomatic, cognitive-complexity, argument-limit, function-result-limit, function-length, max-control-nesting, file-length-limit, line-length-limit, max-public-structs	Yes	Varies
Naming Conventions	confusing-naming, unexported-naming, import-alias-naming, banned-characters, epoch-naming, package-naming, filename-format	Varies	No
Code Quality	add-constant, bool-literal-in-expr, confusing-results, flag-parameter, get-return, modifies-parameter, modifies-value-receiver, nested-structs, optimize-operands-order, unnecessary-stmt, unnecessary-if, unnecessary-format	Varies	Varies
Control Flow & Logic	constant-logical-expr, early-return, if-return, identical-branches, identical-ifelseif-branches, identical-ifelseif-conditions, identical-switch-branches, identical-switch-conditions, unconditional-recursion, useless-break, useless-fallthrough	Varies	No
Correctness & Safety	atomic, datarace, defer, range-val-in-closure, range-val-address, waitgroup-by-value, unchecked-type-assertion, string-of-int, time-equal, time-date	Varies	Varies
Error Handling	unhandled-error, use-errors-new	Yes	Yes
Import Management	imports-blocklist, duplicated-imports, import-shadowing, redundant-import-alias, package-directory-mismatch	Varies	No
Function Design	deep-exit, bare-return, unused-receiver	No	No
Style Enforcement	enforce-map-style, enforce-slice-style, enforce-repeated-arg-type-style, enforce-switch-style, empty-lines, comment-spacings, comments-density	Yes	No
String & Format Validation	string-format, file-header	Yes	No
Struct Tag Validation	struct-tag	Yes	No
Go Modernization	use-any, use-fmt-print, use-slices-sort, use-waitgroup-go, forbidden-call-in-wg-go	Varies	No
Security	call-to-gc, unsecure-url-scheme	No	No
Performance	inefficient-map-lookup	No	Yes
Testing	redundant-test-main-exit	No	No
Build Metadata	redundant-build-tag	No	No

Sources: README.md494-597 RULES_DESCRIPTIONS.md1-1359

Rule Activation Patterns

Extended rules can be activated through three primary configuration patterns, each providing different levels of control.

Sources: config/config.go215-250 config/config.go146-181 README.md315-414

Pattern 1: Enable All Rules

This pattern activates the complete rule set, allowing selective disabling:

Sources: README.md358-413

Pattern 2: Incremental Adoption

Start with default rules and gradually add extended rules:

Sources: README.md348-356

Pattern 3: Explicit Selection

Specify exactly which rules to use:

Sources: README.md315-343

Rule Registration and Discovery

The extended rules are registered in the allRules variable and made available through the configuration system.

Sources: config/config.go16-122 config/config.go146-181

Notable Extended Rules

Complexity Analysis Rules

The complexity rules help identify functions that are difficult to understand and maintain:

• cyclomatic: Measures cyclomatic complexity (decision points)
• cognitive-complexity: Measures cognitive complexity (mental effort to understand)
• function-length: Limits function size by statements and lines
• max-control-nesting: Prevents deeply nested control structures

These rules are covered in detail in Complexity Rules.

Sources: README.md504 README.md512 README.md536 README.md552

Correctness and Safety Rules

These rules detect potential bugs and unsafe patterns:

• datarace: Detects potential data races in goroutines
• atomic: Checks for misuse of sync/atomic package
• defer: Warns about defer gotchas (call-chain, loop, recover, etc.)
• unchecked-type-assertion: Requires checking type assertion results

The datarace rule implementation can be found at rule/datarace.go1-145 and performs AST analysis to detect goroutines capturing variables by reference.

These rules are covered in detail in Correctness and Safety Rules.

Sources: rule/datarace.go1-145 README.md498 README.md513 README.md515 README.md576

Style Enforcement Rules

These rules enforce consistent coding style across the codebase:

• enforce-map-style: Enforces consistent map initialization (make vs literal)
• enforce-slice-style: Enforces consistent slice initialization
• enforce-switch-style: Requires consistent default clause usage
• empty-lines: Prevents heading/trailing newlines in blocks

Sources: README.md522 README.md524 README.md525 README.md520

Naming Convention Rules

Extended naming rules beyond golint's basic checks:

• confusing-naming: Detects method names differing only by capitalization
• unexported-naming: Warns on wrongly named unexported symbols
• epoch-naming: Enforces naming conventions for time variables
• banned-characters: Disallows specific characters in identifiers

The confusing-naming rule at rule/confusing_naming.go1-211 maintains a package-level registry to detect naming conflicts across files.

These rules are covered in detail in Naming Convention Rules.

Sources: rule/confusing_naming.go1-211 README.md507 README.md578 README.md521 README.md499

String and Format Validation

The string-format rule provides powerful pattern matching for string literals:

The rule implementation at rule/string_format.go1-312 uses regex patterns to validate string arguments in specific function calls.

Sources: rule/string_format.go1-312 README.md569

Struct Tag Validation

The struct-tag rule validates struct tags for proper formatting and known keys:

This rule is covered extensively in Struct Tag Validation.

Sources: README.md571

Go Modernization Rules

These rules help adopt newer Go features:

• use-any: Suggests replacing interface{} with any (Go 1.18+)
• use-slices-sort: Suggests using slices.Sort instead of sort.Ints (Go 1.21+)
• use-waitgroup-go: Suggests using WaitGroup.Go method (Go 1.25+)
• forbidden-call-in-wg-go: Prevents misuse of WaitGroup.Go

Sources: README.md588 README.md591 README.md592 README.md535

Configuration Examples

Enabling Extended Rules with Custom Arguments

Many extended rules accept configuration arguments to customize their behavior:

Sources: README.md379-413 RULES_DESCRIPTIONS.md112-836

Rule-Level File Exclusions

Extended rules support file-level exclusions to handle special cases:

Sources: README.md459-488 lint/filefilter.go1-132

Integration with Configuration System

The extended rules integrate seamlessly with revive's configuration system, supporting validation, normalization, and flexible activation patterns.

Sources: config/config.go146-250 config/config.go192-213

Testing Extended Rules

Extended rules are tested using revive's test infrastructure with inline expectations:

Test files use MATCH comments to specify expected failures, which are validated by the test framework at test/utils_test.go

Sources: testdata/confusing_naming1.go1-98 rule/datarace.go19-50

Performance Considerations

Extended rules vary in their performance characteristics:

• Non-typed rules: Fast, analyze only AST structure
• Typed rules: Slower, require type checking information
• Complex pattern matching: Variable cost depending on configuration

The "Typed" column in the rules table at README.md494-597 indicates which rules require type information, which affects linting performance.

Sources: README.md24-25 README.md494-597

Summary

Extended rules provide powerful additional linting capabilities beyond the default golint-compatible set. With approximately 79 additional rules organized into categories like complexity analysis, correctness checking, and style enforcement, they enable teams to enforce comprehensive coding standards tailored to their needs. Extended rules support flexible activation patterns, per-rule configuration, and file-level exclusions, integrating seamlessly with revive's configuration system.

For deep dives into specific rule categories, see:

• Naming Convention Rules
• Complexity Rules
• Struct Tag Validation
• Correctness and Safety Rules

Sources: config/config.go16-122 README.md494-597 RULES_DESCRIPTIONS.md1-1359