Git commit hook that prepends the active branch's JIRA issue number to the commit message

commit-msg.ps1

[CmdletBinding()]
param (
    [Parameter()]
    [string]
    $CommitFile
)

$CommitMessage = Get-Content -Path $CommitFile
$CurrentBranch = (git rev-parse --abbrev-ref HEAD)
$HasMatch = $CurrentBranch -match "[A-Z0-9]{1,10}-?[A-Z0-9]+-\d+"

if ($HasMatch) {
  $IssueNumber = $Matches[0]
  $AlreadyStartsWith = $CommitMessage -like "$($IssueNumber):*"

  if ($AlreadyStartsWith) {
    Write-Host "Nice job including the issue number."
  } else {
    $CommitMessage = "${IssueNumber}:", ($CommitMessage -join "`r`n") -join " "

    Set-Content -Path $CommitFile -Value $CommitMessage

    Write-Host "Prepended issue number $IssueNumber to the commit message. (Use --no-verify to skip)"
  }
}