Warn when managing rewrites with --skip-plugins or --skip-themes

[danielbachhuber]

WordPress' rewrites API requires the rewrite rules to be registered in order to be saved to the database.

If you run wp rewrite flush with --skip-plugins or --skip-themes, you can inadvertently miss saving rewrites registered in plugins or themes.

To help the user realize their mistake, we should provide a warning when they use wp rewrite * with --skip-plugins or --skip-themes to alert them to the fact that some rewrite rules may be missing.

[leepeterson]

@danielbachhuber I think perhaps the language should reflect exactly what did not load themes, or perhaps why themes were not loaded.

Warning: Some rewrite rules may be missing because themes weren't loaded.

...might change to...

Warning: Some rewrite rules may be missing because themes weren't loaded by WP-CLI.

...or...

Warning: Some rewrite rules may be missing because skip-themes is set.

In the case of WordPress living in its own subdirectory, if WP_DEFAULT_THEME is not set, or if register_theme_directory() is not called, a wp-cli user may think a step was missed during setup when "themes weren't loaded" is encountered.

[danielbachhuber]

@leepeterson Sure, can you open a new issue for it?

[leepeterson]

Yes, sir. Thank you.