Configure Code Analyzer

The Code Analyzer checks code and provides information about errors and warnings. To configure the Code Analyzer, place a file named codeAnalyzerConfiguration.json in a resources folder. In this configuration file, you can add custom checks and modify existing checks of the Code Analyzer. Configure the Code Analyzer to enable or disable messages, customize message text, or change the severity of the displayed message.

Note

Changing the severity of a Code Analyzer message does not affect execution. Code is still executed even if the severity of a check has been set to error. Syntax errors will still prevent execution even if their severity is changed or the message disabled.

Configuration file in resources folder

This file configures the Code Analyzer checks performed for the resources folder's parent folder and its subfolders. The configuration is cached at the start of a MATLAB^® session. The MATLAB Editor does not automatically get the latest configuration when you add a new configuration file to a resources folder or update an existing file during a MATLAB session. To refresh the cache, call matlab.codeanalysis.refreshConfiguration.

Verify that the file is a valid JSON file using the matlab.codeanalysis.validateConfiguration function.

Sample Configuration File

This code shows the contents of a sample configuration file. The codeAnalyzerConfiguration.json file uses JSON format, and // designates the text that follows as a comment.

{
// Configuration File Information

    "name": "Acme Corp Guideline",
    "description": "Internal MATLAB Coding Guideline",
    "author" : "Alex",
    "schemaVersion" : "1.0.0",
    "guidelineVersion" : "1.0.0",


// Base Configuration Settings
  
    "baseConfiguration" : "closestParentFolder",
   

// New and Modified Checks

    "checks": 
    {
        "MyOwnCheck" : 
        {
           "rule": 
            {
               "template": "functionCall",
               "functionNames" : "evalin" 
            },
           "severity" : "error",
           "messageText" : "Do not use evalin.",
           "enabled" : true
        },
        "LLMNC" : 
        { 
           "severity" : "error", 
           "limit" : 10, 
           "enabled": true 
        }, 
        "FCNOL" : 
        { 
           "severity" : "error",
           "messageText": "Too many outputs.",  
           "limit" : 15, 
           "enabled": true 
        },
        "AGROW" : 
        {
           "severity" : "info",
           "messageText" : "Growing array in a loop is not recommended",
           "enabled" : false
        }
    }
}

Configuration File Information

You can optionally include the following properties in the configuration file. These properties do not affect the configuration. Each property accepts a string containing the relevant information.

"name" — Name of the configuration file
"description" — Description of the configuration file
"author" - Author name
"schemaVersion" — Schema version in the format "1.2.3"
"guidelineVersion" — Guideline version in the format "1.2.3"

Base Configuration Settings

A configuration file can inherit the rules of a configuration file contained in the resources folder of a parent folder. The property, "baseConfiguration" specifies what base configuration should be used and accepts these values:

"closestParentFolder" (default) — Use the configuration file found in the closest parent folder. If "baseConfiguration" is not defined, then the "closestParentFolder" setting is used.
"factory" — Use the standard MATLAB Code Analyzer configuration.

Add Custom Checks for Existing Functions

You can configure the Code Analyzer to display a check when specific functions are used. To create a new check, you must assign a check ID that is a valid MATLAB identifier. For example, define "MyOwnCheck" to check for an evalin function call.

The "MyOwnCheck" check has these properties:

Property Name	Example	Description
`"rule"`	`"rule": { "template" : "functionCall", "functionNames" : "evalin" }`	Define the rules for the custom check. The `"rule"` field contains a JSON array containing these fields: `"template"` — Define the template that triggers the message. Currently, `"functionCall"` is the only accepted template, and the message is generated when the function is called. `"functionNames` — Define the names of the functions that trigger the custom check. Specify a string or string array containing the function names.
`"messageText"` (optional)	`"messageText" : "Do not use evalin."`	Specify the text displayed in the Code Analyzer message.
`"severity"` (optional)	`"severity" : "error"`	Specify the check severity as `"warning"`, `"error"`, or `"info"`. Messages that have been changed to `"error"` do not prevent execution.
`"enabled"` (optional)	`"enabled": true`	Specify whether this check is enabled in the MATLAB Editor.

Configure Maximum Input and Output Arguments

You can configure the Code Analyzer to limit the number of input and output arguments for a function. Use the check ID "FCNIL" to specify the maximum number of input arguments for a function. Use the check ID "FCNOL" to specify the maximum number of output arguments.

The "FCNIL" and "FCNOL" checks have these properties:

Property Name	Example	Description
`"messageText"` (optional)	`"messageText" : "Too many outputs."`	Specify the text displayed in the Code Analyzer message.
`"severity"` (optional)	`"severity" : "error"`	Specify the check severity as `"warning"`, `"error"`, or `"info"`. Messages that have been changed to `"error"` do not prevent execution.
`"limit"` (optional)	`"limit" : 10`	Specify the maximum number of arguments.
`"enabled"` (optional)	`"enabled": true`	Specify whether this check is enabled in the MATLAB Editor.

Configure Maximum Characters Per Line, Lines In A Function, and Nested Control Statements

You can configure the maximum characters per line, lines in a function, and nested control statements. Use the check ID "FCNLL" to specify the maximum number of lines of code for a function. Use the check ID "LLMNC" to specify the maximum number of characters (including whitespaces) in a line. Use the check ID "MNCSN" to specify the maximum number of control statements, such as for and if, that can be nested.

The "FCNLL", "LLMNC", and "MNCSN" checks have these properties:

Property Name	Example	Description
`"messageText"` (optional)	`"messageText" : "Too many outputs."`	Specify the text displayed in the Code Analyzer message.
`"severity"` (optional)	`"severity" : "error"`	Specify the check severity as `"warning"`, `"error"`, or `"info"`. Messages that have been changed to `"error"` do not prevent execution.
`"limit"` (optional)	`"limit" : 10`	Specify the maximum number of arguments.
`"enabled"` (optional)	`"enabled": true`	Specify whether this check is enabled in the MATLAB Editor.

Modify Existing Code Analyzer Checks

You can use the configuration file to modify existing Code Analyzer checks. Use the check ID you want to modify as the check name. Then, specify the properties you want to modify and their new values. For example, to disable a check in the editor, specify: "enabled" : false.

To identify the check ID for checks in a given file, use codeIssues. For a full list of configurable checks, see Index of Code Analyzer Checks.

The built-in Code Analyzer checks have these properties:

Property Name	Example	Description
`"messageText"` (optional)	`"messageText" : "Growing array in a loop is not recommended"`	Specify the text displayed in the Code Analyzer message
`"severity"` (optional)	`"severity" : "info"`	Specify the check severity as `"warning"`, `"error"`, or `"info"`. Messages that have been changed to `"error"` do not prevent execution.
`"enabled"` (optional)	`"enabled" : true`	Specify whether this check is enabled in the MATLAB Editor.