[wp-trac] [WordPress Trac] #41488: Customize: uncaught JS error with namespaced nav menu fallbacks

[WordPress Trac]

#41488: Customize: uncaught JS error with namespaced nav menu fallbacks
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 Reporter:  dlh           |       Owner:
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  4.9
Component:  Customize     |     Version:  4.3
 Severity:  normal        |  Resolution:
 Keywords:  has-patch     |     Focuses:
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Comment (by westonruter):

 @dlh you've found something very interesting!

 Given `preg_replace( '#^(.)#', '$1' . json_encode( '\hello\world' ), ' '
 )` I would expect it to output:

 `"\\hello\\world"`

 But instead it outputs:

 `"\hello\world"`

 Compare this with `str_replace( ' ', ' ' . json_encode( '\hello\world' ),
 ' ' )`:

 `"\\hello\\world"`

 So yeah, it seems that not only does the pattern need escaping with PCRE
 but also the replacement, even when there are no capture groups!

 By using `preg_quote()` on the ''replacement'' value, it also fixes the
 issue: [attachment:41488.3.diff].

 This seems like a better approach, yes? I wonder how many other instances
 of `preg_replace()` have this problem in code I've written.

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Ticket URL: <https://core.trac.wordpress.org/ticket/41488#comment:5>
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