Code Review Helper Function for Git in PowerShell

I wrote the following article for work after finding a particularly useful function for code review as first talked about in this article.

You can use PowerShell and Git to build a helper function for showing the different between develop and a branch under review; outputting a diff file like this which can help at least establish what needs to be reviewed:

The “code-review” function we’ll add does the following:

• Get a list of log entries in the branch not in develop
• Get a full diff between the branch and develop
• Reverses the log so it’s in ascending chronological order
• Output them to diff files
• Open them in Notepad++

I find this immensely useful for quickly checking how far a branch is away from develop and summarising the changes to merge. See below for a guide on setting this up:

Pre-requisites

• Git must be installed and available on the command line
• Notepad++ (x86) must be installed

Setting up a PowerShell Profile

Powershell profiles are scripts loaded whenever you open Powershell under a particular user. They can be used to create helper functions, alias programs etc.

If you use PoshGit you’ll already have a local Powershell Profile and can skip this step as it creates a profile for you.

1. Go to your “Documents” folder in Windows Explorer (e.g: C:\Users\luke.merrett\Documents)
2. If it doesn’t exist already;create a folder called “WindowsPowerShell”
3. Inside that folder create a new file called “Microsoft.PowerShell_profile.ps1”

Anything added to that PS1 script will now be run when you open Powershell as your current user.

Adding the Helper Function to the Profile

Open the “Microsoft.PowerShell_profile.ps1” and append the following to it:

 <#
    .SYNOPSIS
      Runs a Git command on the current branch that displays all commits
      in ascending order that haven't been merged into develop

    .EXAMPLE
      code-review
      # Displays differences between the current branch and origin/develop    

    .EXAMPLE 
      code-review feature/differentbasebranch
      # Displays differences between the current branch and feature/differentbasebranch
	  
	.EXAMPLE 
      code-review 7bcedc50adfbddffd7e5918a457b5f0d807a68d1
      # Displays the changes after the specified commit up to the head of the current branch

    .EXAMPLE 
      code-review -OriginalBranch feature/differentbasebranch
      # Displays differences between the current branch and feature/differentbasebranch
  #>
function code-review {

    param ( 
        $OriginalBranch = "origin/develop"
    )

	# Need to use Invoke-Expression otherwise the parameter stops git log working correctly
	Invoke-Expression "git log $OriginalBranch..head --name-status --reverse > Review_Summary.diff"
	Invoke-Expression "git log $OriginalBranch..head -p --reverse > Review_Log.diff"
	Invoke-Expression "git diff $OriginalBranch..head -p --reverse > Review_Diff.diff"
	
	if (Get-Command "notepad++" -ErrorAction SilentlyContinue) 
	{
		notepad++ Review_Summary.diff
		notepad++ Review_Log.diff
		notepad++ Review_Diff.diff
	}
}

Prepare PowerShell

As with pretty much anything in Powershell you need to Set-ExecutionPolicy.

1. Open Powershell as an Administrator
2. Run “Set-ExecutionPolicy Unrestricted”

Use the Function

Now the function is ready to use and will work inside any git repository. To use it:

1. Open up Powershell as your standard user
2. CD into a git repository that is ahead of develop
3. Type “code-review” and press enter

If you want to see more advanced examples of usage; run “Get-Help code-review” and “Get-Help code-review -examples”.