renovate/lib/modules/versioning/regex/readme.md

Regular Expression Versioning is designed to be a flexible fallback versioning approach if Renovate's other versioning schemes don't do the job.

The regex scheme makes use of Regular Express capture groups. The valid capture groups for regex versioning are:

• major, minor, and patch: at least one of these must be provided. When determining whether a package has updates, these values will be compared in the standard semantic versioning fashion. If any of these fields are omitted, they will be treated as if they were 0 -- in this way, you can describe versioning schemes with up to three incrementing values.
• build: this capture group can be used after you've already used the major, minor and patch capture groups and need a fourth version part. build updates are handled like patch updates.
• revision: this capture group can be used after you've already used the build capture groups and need a fifth version part. revision updates are handled like patch updates.
• prerelease: this value, if captured, will mark a given release as a prerelease (e.g. unstable). If this value is captured and you have configured "ignoreUnstable": true, the given release will be skipped.
• compatibility: this value defines the "build compatibility" of a given dependency. A proposed Renovate update will never change the specified compatibility value. For example, if you are pinning to 1.2.3-linux (and linux is captured as the compatibility value), Renovate will not update you to 1.2.4-osx.

The compatibility concept was originally introduced for Docker versioning but sometimes package authors may use/misuse suffixes to mean compatibility in other versioning schemes.

Here is an example of using regex versioning to correct behavior of the guava Maven package, which misuses suffixes as compatibility indicators:

{
  "packageRules": [
    {
      "matchPackageNames": ["com.google.guava:guava"],
      "versioning": "regex:^(?<major>\\d+)(\\.(?<minor>\\d+))?(\\.(?<patch>\\d+))?(-(?<compatibility>.*))?$"
    }
  ]
}

Here is another example, this time for handling python Docker images, which use both pre-release indicators as well as version suffixes for compatibility:

{
  "packageRules": [
    {
      "matchDatasources": ["docker"],
      "matchPackageNames": ["python"],
      "versioning": "regex:^(?<major>\\d+)\\.(?<minor>\\d+)\\.(?<patch>\\d+)(?<prerelease>[^.-]+)?(-(?<compatibility>.*))?$"
    }
  ]
}

Here is another example, this time for handling Bitnami Docker images, which use build and revision indicators as well as version suffixes for compatibility:

{
  "packageRules": [
    {
      "matchDatasources": ["docker"],
      "matchPackageNamees": ["bitnami/**", "docker.io/bitnami/**"],
      "versioning": "regex:^(?<major>\\d+)\\.(?<minor>\\d+)\\.(?<patch>\\d+)(?:-(?<compatibility>.+)(?<build>\\d+)-r(?<revision>\\d+))?$"
    }
  ]
}