[RULE] PSScriptAnalyzerSettingsSchema

User Story

• As a writer of PSScriptAnalyzer settings files
• I want static code checking of the structure of PSScriptAnalyzer settings files
• so that I can catch schematic violations early and easily.

Specification Details

The static schema for an Invoke-ScriptAnalyzer -Settings hashtable is not formally documented in a rigorous format at present. However, the current implementation implicitly adheres to the following as expressed using JSON Schema (with the exception of case-sensitivity):

{
  "$schema": "http://json-schema.org/draft-07/schema",
  "title": "PSScriptAnalyzerSettings",
  "type": "object",
  "definitions": {
    "SeverityString": {
      "type": "string",
      "pattern": "Error|Warning|Information"
    },
    "stringOrStrings": {
      "oneOf": [
        {
          "type": "string"
        },
        {
          "type": "array",
          "items": {
            "type": "string"
          }
        }
      ]
    }
  },
  "properties": {
    "CustomRulePath": {
      "$ref": "#/definitions/stringOrStrings"
    },
    "ExcludeRules": {
      "$ref": "#/definitions/stringOrStrings"
    },
    "IncludeDefaultRules": {
      "type": "boolean"
    },
    "IncludeRules": {
      "$ref": "#/definitions/stringOrStrings"
    },
    "RecurseCustomRulePath": {
      "type": "boolean"
    },
    "Rules": {
      "type": "object",
      "additionalProperties": {
        "type": "object"
      }
    },
    "Severity": {
      "oneOf": [
        {
          "$ref": "#/definitions/SeverityString"
        },
        {
          "type": "array",
          "items": {
            "$ref": "#/definitions/SeverityString"
          }
        }
      ]
    }
  },
  "additionalProperties": false
}

The static schema of an Invoke-ScriptAnalyzer -Settings hashtable, as currently implemented and as expressed above (but with the addition of global case-insensitivity), shall serve as the specification for the proposed "PSScriptAnalyzerSettingsSchema" rule. Additional requirements are as follows:

• The schema utilized by the "PSScriptAnalyzerSettingsSchema" rule MUST be enforced by the Invoke-ScriptAnalyzer command.
• The implementation of the "PSScriptAnalyzerSettingsSchema" rule SHOULD share source code for validation logic with the Invoke-ScriptAnalyzer command in an appropriately modular fashion such that changes to the aforementioned schema's specification correspond one-to-one to changes in the source code.

PSScriptAnalyzer Version

The latest version of PSScriptAnalyzer as of this writing is 1.18.1.

Start by locating the Invoke-ScriptAnalyzer command and the proposed PSScriptAnalyzerSettingsSchema rule, then trace how settings are currently validated. Done means the specified case-insensitive schema is enforced by the command and the rule shares validation logic with it as required.