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How would site admins, or log monitoring tools, know when there's a file read error if we suppress errors?

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How would site admins, or log monitoring tools, know when there's a file read error if we suppress errors?

For me such error output only makes sense for files which must be readable. The function parses all php-files in theme's subdirectories, not only template files, also which are not relevant for templating. Would be better to have some predefined folders (theme dir, /templates, ...) for parsing (also for performance reasons), but this would may break compatibility with some themes.