Closes #2264 Migrate path aliases for nodes if they exist, otherwise turn on Pathauto.

[trackleft]

Description

This PR checks the alias field for nodes on the source site during a migration, and determines whether to turn on Pathauto or not, on a node by node basis.

Related issues

Closes #2264

How to test

Run az_migration
See paths migrated, or Pathauto turned on.

Types of changes

Arizona Quickstart (install profile, custom modules, custom theme)

• Patch release changes
  • Bug fix
  • Accessibility, performance, or security improvement
  • Critical institutional link or brand change
  • Adding experimental module
  • Update experimental module
• Minor release changes
  • New feature
  • Breaking or visual change to existing behavior
  • Upgrade experimental module to stable
  • Enable existing module by default or database update
  • Non-critical brand change
  • New internal API or API improvement with backwards compatibility
  • Risky or disruptive cleanup to comply with coding standards
  • High-risk or disruptive change (requires upgrade path, risks regression, etc.)
• Other or unknown
  • Other or unknown

Drupal core

• Patch release changes
  • Security update
  • Patch level release (non-security bug-fix release)
  • Patch removal that's no longer necessary
• Minor release changes
  • Major or minor level update
• Other or unknown
  • Other or unknown

Drupal contrib projects

• Patch release changes
  • Security update
  • Patch or minor level update
  • Add new module
  • Patch removal that's no longer necessary
• Minor release changes
  • Major level update
• Other or unknown
  • Other or unknown

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[trackleft]

I'm going to try this

  path/pathauto:
    - plugin: str_replace
      regex: true
      source: alias
      search: /./
      replace: 0
    - plugin: default_value
      default_value: 1
  path/alias:
    plugin: skip_on_empty
    source: alias
    method: process

[trackleft]

The above didn't work, but the following does.

  path/pathauto:
    -
      plugin: str_replace
      regex: true
      source: alias
      search: /.*$/
      replace: 0
    -
      plugin: default_value
      default_value: 1
    -
      plugin: static_map
      map:
        '00': 0
        '0': 0
        '1': 1
  path/alias:
    plugin: skip_on_empty
    source: alias
    method: process

When path alias DOES NOT EXIST on source site.

^ "|                             $Source                               |"
^ "---------------------------------------------------------------------"
  

^ "---------------------------------------------------------------------"
^ "|                           $Destination                            |"
^ "---------------------------------------------------------------------"
  "path" => array:1 [
    "pathauto" => 1
  ]

When a path alias EXISTS on source site.

^ "|                             $Source                               |"
^ "---------------------------------------------------------------------"
  "alias" => "/projects/alumni/2020/ampersand-modern-workspace-campus"

^ "---------------------------------------------------------------------"
^ "|                           $Destination                            |"
^ "---------------------------------------------------------------------"
  "path" => array:2 [
    "pathauto" => 0
    "alias" => "/projects/alumni/2020/ampersand-modern-workspace-campus"
  ]

Other things to consider:

Default value is set to '1' if fed a 0
Normally the str_replace returns '00', not sure why the regex is doing that.
search: /.*/ also returns '00' if a value exists in alias