acampbel / Simple-Code-Analyzer-Configuration

A simple Code Analyzer configuration file, with example code that illustrates the code issues the configuration will enable you to identify.

Simple Code Analyzer Configuration

This repository provides a simple Code Analyzer configuration example that increases the strictness of the Code Analyzer in MATLAB®.

The Code Analyzer:

• checks your code for code violations and suggestions for improvement
• runs continuously as you type in the MATLAB Editor
• can be used interactively with the Code Analyzer Report
• can be used programmatically with the codeIssues function
  
  
  

How to use the simple Code Analyzer configuration

To get started with the Code Analyzer configuration:

• Copy the codeAnalyzerConfiguration.json file to the "resources" folder at the root of your codebase
  • Note: If the root of your codebase does not have a "resources" folder, you will need to create one
• Analyze your codebase for issues using:
  • Code Analyzer app (codeAnalyzer), or
  • codeIssues function
    
    
    

Trying out the simple Code Analyzer configuration in MATLAB Online™

• Click on the "Open in MATLAB Online" badge at the top of this README.md
  • This will automatically clone this repository to your MATLAB Online account and open the GettingStarted.mlx file
• Walk through the GettingStarted.mlx file
  • Analyze the codebase before applying the simple Code Analyzer configuration
  • Copy the codeAnalyzerConfiguration.json file to the "resources" folder
  • Execute matlab.codeanalysis.refreshConfiguration for the JSON file to take effect
  • Analyze the codebase again after applying the simple Code Analyzer configuration

Disclaimer:

• Code Analyzer app is not yet supported in MATLAB Online
• For now, please use the codeIssues function in MATLAB Online to see code analysis results using the Code Analyzer configuration
  
  
  

Details of the checks configured by this simple Code Analyzer configuration

The table below lists all of the Code Analyzer checks that are enabled or modified by this simple Code Analyzer configuration.

Check ID	Issue Being Identified	Limit	Severity	Reasoning
DISALLOWEVAL	All uses of "eval" and "evalc"		Error	"eval" and "evalc" are inefficient, make code difficult to understand and maintain, are hard to debug, and can lead to security concerns if untrusted user code is passed to them.
FCNLL	Very long functions	2000 lines	Error	Long functions make code more difficult to understand and maintain. It is helpful to refactor long functions into several smaller functions that are called by one main function.
LLMNC	Very long lines	1000 characters	Error	Long lines make code more difficult to understand and maintain. It is helpful to break long lines into multiple simpler statements, or into a single statement split across several shorter lines.
MNCSN	Deeply nested control statements	10 levels	Error	Deeply nested control statements make code difficult to understand and maintain.
FCNIL	Too many input arguments	10 arguments	Warning	Too many input arguments make functions difficult to understand and maintain. In these cases, it can be beneficial to create several simpler functions to accomplish all of the tasks of the original more complicated function.
FCNOL	Too many output arguments	10 arguments	Warning	Too many output arguments make functions difficult to understand and maintain. In these cases, it can be beneficial to return a single output or a few outputs containing multiple pieces of data (such a struct/table/object containing multiple results).
GVMIS	Global variable usage		Raised from warning to error	Global variables are inefficient and make errors difficult to diagnose.
EVLCS	All uses of "eval" and "evalc"		Raised from warning to error	Built-in Code Analyzer check warning that "eval" and "evalc" are inefficient, make code difficult to understand and maintain, are hard to debug, and can lead to security concerns if untrusted user code is passed to them.
NOANS	Use of "ans" as a variable		Raised from warning to error	Using "ans" as a variable is not recommended as "ans" is frequently overwritten by MATLAB.
CHAIN	Chained logical operations		Raised from warning to error	Expressions like a > b > c are often a bug because they are interpreted as (a > b) > c, instead of as a comparison to ensure b is between a and c. To test a > b > c mathematically, use (a > b) && (b > c) for numeric scalars, or (a > b) & (b > c) for numeric arrays.

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