[wp-trac] [WordPress Trac] #63737: Theme update fails, creates duplicate directory after incorrect plugin update attempt

[WordPress Trac]

#63737: Theme update fails, creates duplicate directory after incorrect plugin
update attempt
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 Reporter:  leemon                               |       Owner:  (none)
     Type:  defect (bug)                         |      Status:  new
 Priority:  normal                               |   Milestone:  Awaiting
                                                 |  Review
Component:  Upgrade/Install                      |     Version:  6.8.2
 Severity:  normal                               |  Resolution:
 Keywords:  has-test-info has-screenshots        |     Focuses:
  reporter-feedback close                        |
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Comment (by leemon):

 I've been testing this issue further, and it appears the behavior I
 described is related to the **structure of the theme's ZIP file**.

 I tested the reproduction steps with a default theme (like **Twenty
 Twenty-One**), and it **does not** exhibit the bug. When attempting the
 incorrect plugin update and then the correct theme update, Twenty Twenty-
 One updates as expected, overwriting the existing theme folder.

 The key difference I found is how the ZIP files are structured:

 * The Twenty Twenty-One ZIP file contains a root folder named
 `twentytwentyone`, and all the theme files are **inside** that folder.
 * My custom theme's ZIP file, which initially caused the issue, had its
 theme files directly at the root of the ZIP, **not inside any containing
 folder**.

 When I re-zipped my custom theme's files so that they were **inside a
 folder named `my-theme`** (matching the theme's slug) at the root of the
 ZIP, the issue disappeared. Now, after an incorrect plugin update attempt,
 the subsequent theme update works as expected, correctly overwriting the
 `wp-content/themes/my-theme` directory.

 It seems that the presence of a containing folder within the theme ZIP is
 crucial for WordPress to correctly handle the update process, especially
 after a failed attempt in the wrong installer. This might indicate an
 expectation in the installer's logic that anticipates a single root
 directory within the uploaded ZIP for themes.

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Ticket URL: <https://core.trac.wordpress.org/ticket/63737#comment:11>
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