How to use the command 'phan' (with examples)

Phan is a static analysis tool designed for PHP, which helps developers identify potential bugs in their code before execution. It inspects code for syntax errors, type mismatches, and other issues, providing valuable insights to improve overall code quality. Phan is highly configurable and can be tailored to fit different projects’ needs, making it a versatile tool for PHP developers.

Use case 1: Generate a .phan/config.php in the current directory

Code:

phan --init

Motivation:
Generating a configuration file is a crucial first step when setting up Phan for static analysis. The .phan/config.php file acts as a guide for Phan, helping it understand how to process your codebase. This configuration file includes settings such as which directories to analyze, which files to exclude, and various other options that tailor Phan’s analysis to your specific project needs. By generating this file, you ensure that Phan operates with the correct parameters, leading to more accurate and applicable results.

Explanation:

• --init: This argument instructs Phan to create a basic configuration file .phan/config.php in the current directory. It sets up default settings that you can later customize to match your project’s specific requirements.

Example Output:
After running phan --init, a new configuration file will be created at .phan/config.php, containing default settings that you can edit as needed.

Use case 2: Generate a Phan configuration file using a specific level

Code:

phan --init --init-level 3

Motivation:
Different projects may require varying levels of strictness in static analysis. Phan allows you to specify an initialization level, from 1 (most strict) to 5 (least strict), when creating the configuration file. This flexibility helps balance the thoroughness and performance of the analysis, depending on your project’s complexity and needs. By specifying a level, you can tailor Phan’s sensitivity to code issues according to your requirements, either catching more potential errors or speeding up the analysis process.

Explanation:

• --init: Initializes a basic configuration file.
• --init-level 3: Sets the strictness level of the generated configuration to 3. This level balances performance and thoroughness, giving a moderate level of detail in the analysis.

Example Output:
Running this command will produce a configuration file with level 3 strictness, giving balanced analysis suitable for medium complexity projects.

Use case 3: Analyze the current directory

Code:

phan

Motivation:
Analyzing the current directory is straightforward and essential for identifying potential issues in a PHP project. This use case is particularly useful for running a quick scan of the entire codebase without delving into configuration complexities. It allows developers to get an immediate overview of possible errors and warnings in their code, enabling them to address critical issues early and ensure overall code quality.

Explanation:

• phan: Running the command without additional parameters instructs Phan to analyze the PHP files located in the current directory using the default settings from the existing .phan/config.php file.

Example Output:
Executing phan will output a list of potential error messages, warnings, or notices related to the PHP files in the current directory.

Use case 4: Analyze one or more directories

Code:

phan --directory path/to/directory --directory path/to/another_directory

Motivation:
In many projects, PHP code is dispersed across several directories. Being able to specify multiple directories for analysis ensures comprehensive coverage of your entire codebase. This use case is beneficial for projects with modular architectures where different components reside in separate directories. By clearly listing directories, you can ensure that no crucial parts of your project are overlooked during the analysis process.

Explanation:

• --directory path/to/directory: Specifies a directory for Phan to analyze. You can repeat this argument to add multiple directories.

Example Output:
When executed, Phan will output analysis results for all specified directories, listing potential issues found in each one.

Use case 5: Specify a configuration file

Code:

phan --config-file path/to/config.php

Motivation:
Sometimes, you might want to run Phan with a different configuration than the default .phan/config.php. Using an alternative configuration file allows for flexible analysis scenarios, such as testing different sets of rules or analyzing different parts of the project with distinct configurations. This is ideal when working on different features simultaneously that each require specialized analysis settings.

Explanation:

• --config-file path/to/config.php: Directs Phan to use the specified configuration file instead of the default. This argument allows for custom settings and paths, making it adaptable to different project needs.

Example Output:
Using a specified config file, Phan will read the settings and run the analysis based on those parameters, providing tailored results accordingly.

Use case 6: Specify the output mode

Code:

phan --output-mode json

Motivation:
Different projects and teams have different preferences for how analysis results are presented. By allowing multiple output modes, Phan caters to specific needs for integration with other tools, reporting, or user consumption. The JSON format is particularly useful for integrating with automated systems or further processing with scripts.

Explanation:

• --output-mode json: This argument specifies that the analysis output should be formatted as JSON. Other modes might include text, verbose, csv, etc., each catering to different use cases for reporting or team integration.

Example Output:
Phan will output the analysis results in JSON format, which might include structured error data that can easily be parsed or integrated into other systems.

Use case 7: Specify the number of parallel processes

Code:

phan --processes 4

Motivation:
Running analyses on large codebases can be time-consuming. By specifying multiple processes, Phan can perform the analysis in parallel, significantly reducing the time required. This capability is particularly beneficial in continuous integration processes where time efficiency is crucial.

Explanation:

• --processes 4: Instructs Phan to use four parallel processes for the analysis. Depending on your machine’s resources, you can adjust this number to optimize performance and resource utilization.

Example Output:
The analysis process will be divided among four instances, speeding up the time it takes to complete the review of code and returning results more quickly.

Conclusion:

Phan is an adaptable and robust static analysis tool for PHP, offering numerous customizable options to meet different project requirements. Whether initializing configuration files, analyzing directories, or setting output preferences, Phan allows developers to identify and fix potential issues efficiently, ensuring higher code quality and reliability in their PHP applications.