Null type issue

[purplepixie]

Resolve issue #30 - added error handling for empty array and optional exception, also suppress warnings from unpack()

[Copilot]

Pull Request Overview

This PR addresses issue #30 by improving error handling for DNS response parsing failures. The changes introduce a new exception type for invalid responses and add safeguards against unpack() failures when parsing DNS answer headers.

Key Changes:

• Added InvalidResponse exception class for DNS response parsing errors
• Implemented error handling for empty/null array results from unpack() with optional exception throwing
• Suppressed warnings from unpack() using the @ operator

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/PurplePixie/PhpDns/Exceptions/InvalidResponse.php	New exception class for handling invalid DNS response errors
src/PurplePixie/PhpDns/DNSQuery.php	Added response exception flag, error handling for unpack failures, and getter/setter methods for the new flag

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[Copilot]

The condition $ans_header === null is redundant. The unpack() function in PHP only returns false on failure, never null. The check should be simplified to if ($ans_header === false).

Suggested change

	if ($ans_header === null || $ans_header === false || !is_array($ans_header)) // the unpack has failed - we assume an invalid return
	if ($ans_header === false) // the unpack has failed - we assume an invalid return

[Copilot]

The else block is unnecessary since the if block returns an array. The code in the else block (lines 224-227) should be moved after the if block and the else removed to reduce nesting and improve readability.

[Copilot]

Using the @ operator to suppress errors is generally discouraged as it hides potential issues and makes debugging harder. Consider removing the @ operator and handling the false return value explicitly, which you're already doing in the subsequent if statement.

Suggested change

	$ans_header = @unpack('ntype/nclass/Nttl/nlength', $ans_header_bin);
	$ans_header = unpack('ntype/nclass/Nttl/nlength', $ans_header_bin);