protolint

protolint is a fast, pluggable linting and fixing utility for Protocol Buffer files that enforces the official Google Protocol Buffer style guide. It operates without requiring compilation, making it ideal for rapid development feedback.

Key Features:

Official Style Guide Compliance: Rules correspond exactly to Google's Protocol Buffer style guide recommendations
Fast Performance: Operates without compilation, providing rapid feedback during development
Automatic Fixing: Built-in auto-fix capability for many style violations and formatting issues
Proto2 and Proto3 Support: Full compatibility with both Protocol Buffer syntax versions
Inline Rule Disabling: Selective rule disabling through comments for API compatibility requirements
Pluggable Architecture: Support for custom rule plugins and organization-specific standards
Comprehensive Coverage: Validates naming conventions, field ordering, imports, indentation, and syntax
Configuration Flexibility: YAML-based configuration for team-specific linting preferences

protolint documentation

Version in MegaLinter: 0.55.6
Visit Official Web Site
See How to configure protolint rules
- If custom .protolintrc.yml config file isn't found, .protolintrc.yml will be used
See How to disable protolint rules in files
See Index of problems detected by protolint

Configuration in MegaLinter

Enable protolint by adding PROTOBUF_PROTOLINT in ENABLE_LINTERS variable
Disable protolint by adding PROTOBUF_PROTOLINT in DISABLE_LINTERS variable

Enable autofixes by adding PROTOBUF_PROTOLINT in APPLY_FIXES variable

Variable	Description	Default value
PROTOBUF_PROTOLINT_ARGUMENTS	User custom arguments to add in linter CLI call Ex: `-s --foo "bar"`
PROTOBUF_PROTOLINT_COMMAND_REMOVE_ARGUMENTS	User custom arguments to remove from command line before calling the linter Ex: `-s --foo "bar"`
PROTOBUF_PROTOLINT_FILTER_REGEX_INCLUDE	Custom regex including filter Ex: `(src\\|lib)`	Include every file
PROTOBUF_PROTOLINT_FILTER_REGEX_EXCLUDE	Custom regex excluding filter Ex: `(test\\|examples)`	Exclude no file
PROTOBUF_PROTOLINT_CLI_LINT_MODE	Override default CLI lint mode - `file`: Calls the linter for each file - `project`: Call the linter from the root of the project	`file`
PROTOBUF_PROTOLINT_FILE_EXTENSIONS	Allowed file extensions. `"*"` matches any extension, `""` matches empty extension. Empty list excludes all files Ex: `[".py", ""]`	`[".proto"]`
PROTOBUF_PROTOLINT_FILE_NAMES_REGEX	File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files Ex: `["Dockerfile(-.+)?", "Jenkinsfile"]`	Include every file
PROTOBUF_PROTOLINT_PRE_COMMANDS	List of bash commands to run before the linter	None
PROTOBUF_PROTOLINT_POST_COMMANDS	List of bash commands to run after the linter	None
PROTOBUF_PROTOLINT_UNSECURED_ENV_VARIABLES	List of env variables explicitly not filtered before calling PROTOBUF_PROTOLINT and its pre/post commands	None
PROTOBUF_PROTOLINT_CONFIG_FILE	protolint configuration file nameUse `LINTER_DEFAULT` to let the linter find it	`.protolintrc.yml`
PROTOBUF_PROTOLINT_RULES_PATH	Path where to find linter configuration file	Workspace folder, then MegaLinter default rules
PROTOBUF_PROTOLINT_DISABLE_ERRORS	Run linter but consider errors as warnings	`false`
PROTOBUF_PROTOLINT_DISABLE_ERRORS_IF_LESS_THAN	Maximum number of errors allowed	`0`
PROTOBUF_PROTOLINT_CLI_EXECUTABLE	Override CLI executable	`['protolint']`

IDE Integration

Use protolint in your favorite IDE to catch errors before MegaLinter !

	IDE	Extension Name	Install
	IDEA	Protocol Buffer Linter
	Visual Studio Code	VSCode Protolint

MegaLinter Flavors

This linter is available in the following flavors

Flavor	Description	Embedded linters
all	Default MegaLinter Flavor	127
c_cpp	Optimized for pure C/C++ projects	57
documentation	MegaLinter for documentation projects	50
dotnet	Optimized for C, C++, C# or VB based projects	65
dotnetweb	Optimized for C, C++, C# or VB based projects with JS/TS	74
go	Optimized for GO based projects	52
java	Optimized for JAVA based projects	55
javascript	Optimized for JAVASCRIPT or TYPESCRIPT based projects	60
php	Optimized for PHP based projects	55
python	Optimized for PYTHON based projects	66
ruby	Optimized for RUBY based projects	51
rust	Optimized for RUST based projects	51
salesforce	Optimized for Salesforce based projects	55
swift	Optimized for SWIFT based projects	51
terraform	Optimized for TERRAFORM based projects	55

Behind the scenes

How are identified applicable files

File extensions: .proto

How the linting is performed

protolint is called one time by identified file (file CLI lint mode)

Example calls

protolint lint myfile.proto

protolint lint --config_path .protolintrc.yml myfile.proto

protolint lint -fix --config_path .protolintrc.yml myfile.proto

Help content

Usage of lint:
  -add-reporter value
      Adds a reporter to the list of reporters to use. The format should be 'name of reporter':'Path-To_output_file'
  -auto_disable value
      mode that the command line automatically disable some of the problems. Available auto_disable are "next" and "this".
  -config_dir_path string
      path/to/the_directory_including_protolint.yaml
  -config_path string
      path/to/protolint.yaml. Note that if both are set, config_dir_path is ignored.
  -fix
      mode that the command line automatically fix some of the problems
  -no-error-on-unmatched-pattern
      exits with 0 when no file is matched
  -output_file string
      path/to/output.txt
  -plugin value
      plugins to provide custom lint rule set. Note that it's necessary to specify it as path format'
  -reporter value
      formatter to output results in the specific format. Available reporters are "plain"(default), "junit", "json", "sarif", and "unix".
  -v  verbose output that includes parsing process details

Installation on mega-linter Docker image

Dockerfile commands :

# renovate: datasource=docker depName=yoheimuta/protolint
ARG PROTOBUF_PROTOLINT_VERSION=0.55.6
FROM yoheimuta/protolint:${PROTOBUF_PROTOLINT_VERSION} AS protolint
COPY --link --from=protolint /usr/local/bin/protolint /usr/bin/