这些水平线在PhpStorm IDE中代表什么？

Question

They do not appear when I put the condition inside the try {}

Answer 1

Phpstorm highlights those lines because one or more of the functions being called throws an Exception. There's three ways to go around this issue.

Add a try / catch block

you can surround the highlighted code with a try/ catch block, and then do something with the Exception (ex: logging the message to the console).

public function get() {
    try {
        throw new Exception();
    }
    catch(Exception $e) {
        // do something
    }
}

Add a phpdoc comment to the function

If you wish to let the potential Exception bubble up, you can simply add a phpdoc comment to your function. Be aware though, that unless you list every potential Exception, or the generic Exception type, Phpstorm will then warn you about missing @throws statement.

/**
 * @throws Exception
 */
public function get() {
    throw new Exception();
}

disable or alter the IDE settings

The "Unhandled Exception" warning in Phpstorm is considered to be a warning, and not a syntax highlight. As such, you can either enable or disable it, or adjust its severity level. You can find the related setting in Settings > Editor > Inspections and then selecting PHP > Error handling > Unhandled expection

I would advise against disabling the highlight, knowing when and where an Exception might thrown can help in preventing bugs and making the codebase generally more stable.

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Note that you can change the actual style of the warning, but doing so will affect any other warning of the same severity level. To do so, go in Settings > Editor > Color scheme > General > Errors and Warnings and select the warning level that applies (Warning by default)