Feature: Converting to and from different IssueTypes (like sub-tasks)

Context

Iv'e been looking for commands that can change an Issue to/from subtasks (and other types as well) as this is possible using the GUI.

New-JiraIssue -Parent <key> -IssueType 'Sub-Task' (do exist)

Set-JiraIssue -Key <key> -IssueType 'Sub-task' -Parent <key> (doesn't exist)

Maybe this would be possible using the -Fields argument? But that's a rabbits hole.

Description

A new command seems necessary for these actions.

Convert-JiraIssueType

ArgSet 1

-Key string mandatory
-IssueType string mandatory ('Sub-task' not allowed)
-Force

ArgSet 2

-Key string mandatory
-Parent string mandatory (implies the issue type will be 'Sub-task')
-Force

# Create a main task in a project labeled 'MYPROJ' using 'jane' as reporter
New-JiraIssue -Project 'MYPROJ' -Summary 'Main example' -IssueType 'Task' -Reporter 'jane'

Key              Summary
---              -------
MYPROJ-1         Main example

# Creta a subtask to MYPROJ-1
New-JiraIssue -Project 'MYPROJ' -Summary 'Sub example' -IssueType 'Sub-task' -Parent 'MYRPOJ-1' -Reporter 'jane'

Key              Summary
---              -------
MYPROJ-2         Sub example

# Create a task and then convert it to a subtask of MYPROJ-1
New-JiraIssue -Project 'MYPROJ' -Summary 'Second example' -IssueType 'Task' -Reporter 'jane'

Key              Summary
---              -------
MYPROJ-3         Second example

Convert-JiraIssueType -Key 'MYPROJ-3' -Parent 'MYPROJ' -Force

Key              Summary
---              -------
MYPROJ-3         Second example

# Convert a subtask to a task
Convert-JiraIssueType -Key 'MYPROJ-2' -IssueType 'Task' -Force

Key              Summary
---              -------
MYPROJ-2         Second example

Additional Information

Also, piping a stored JIRA object, that's been changed, to Set-JiraIssue should set all properties changed (if in an allowed combination).

New-JiraIssue -Project 'MYPROJ' -Summary 'Third example' -IssueType 'Task' -Reporter 'jane'

Key              Summary
---              -------
MYPROJ-4         Second example

$task = Get-JiraIssue -Key 'MYPROJ-4'

$task.parent.key = 'MYPROJ-1'
$task.issuetype.subtask = $false

$task | Set-JiraIssue -Force

Key              Summary
---              -------
MYPROJ-4         Second example

AtlassianPS / JiraPS