Arduino Lint inspects Arduino projects for common problems. This is done by checking the project against a series of "rules", each of which is targeted to detecting a specific potential issue. Only the rules of relevance to the project being linted are applied.

Rule documentation

Additional information is available for each of the Arduino Lint rules, organized by project type:

Rule ID

In order to allow particular rules to be referenced unequivocally, each has been assigned a permanent unique identification code (e.g., SS001).

Rule level

In addition to checking for critical flaws, Arduino Lint also advocates for best practices in Arduino projects. For this reason, not all rule violations are treated as fatal linting errors.

A violation of a rule is assigned a level according to its severity. In cases where a rule violation indicates a serious problem with the project, the violation is treated as an error, and will result in a non-zero exit status from the arduino-lint command. In cases where the violation indicates a possible problem, or where the rule is a recommendation for an optional improvement to enhance the project user's experience, the violation is treated as a warning. It is hoped that these warning-level violations will be given consideration by the user, but they do not affect the arduino-lint exit status.

Of the hundreds of rules provided by Arduino Lint, only the ones relevant to the current target project are applied, with the rest disabled.

The rule levels and enabled subset of rules is dependent on the target project type and how the user has configured Arduino Lint via the command line flags and environment variables.

Projects and "superprojects"

Arduino projects may contain other Arduino projects as subprojects. For example, the libraries bundled with an Arduino boards platform. These subprojects may, in turn, contain their own subprojects, such as the example sketches included with a platform bundled library.

Arduino Lint also lints any subprojects the target project might contain. The type of the top level "superproject" is a factor in the configuration of some rules. For example, there is no need to take Library Manager requirements into consideration in the case of a platform bundled library, since it will never be distributed via that system.

Uh oh!