THRIFT-6047: Limit struct read/write recursion depth in PHP library

[Jens-G]

Summary

• Adds incrementRecursionDepth() / decrementRecursionDepth() to TProtocol
• Limit is 64; throws TProtocolException(DEPTH_LIMIT) when exceeded
• TBase::read / TBase::write wrap with try/finally to guarantee counter restoration
• PHP generator emits the calls for all generated struct read/write methods

Test plan

• lib/php/test/Unit/Lib/Protocol/TProtocolTest.php covers allow/reject/restore

🤖 Generated with Claude Code

Co-Authored-By: Claude Sonnet 4.6 noreply@anthropic.com

[sveneld]

Functionally solid — see two style nits inline. Will follow up on the binary_inline / integration-test items separately.

[sveneld]

Style: the try { ... } block body isn't indented relative to the surrounding code, so the body sits at the same column as try { itself. PSR-12 expects the body to be one level deeper. The same shape is in writeStruct below. CI is green only because phpcs doesn't enforce Generic.WhiteSpace.ScopeIndent for this rule, but visually it reads as if the try had no body. Suggest:

Suggested change

	$xfer += $input->readStructBegin($fname);
	$input->incrementRecursionDepth();
	try {
	$xfer += $input->readStructBegin($fname);

…and reindent the matched closing brace + every line in between.

[sveneld]

Same indent issue as in readStruct — body of try { is one level shallower than it should be.

[sveneld]

Nit: PHPUnit canonical way to express “the code under test must not throw and has no value to assert on” is $this->expectNotToPerformAssertions(); at the top of the test, rather than a trailing assertTrue(true). Same for testDecrementRecursionDepthRestoresCapacity below.

[sveneld]

Same nit — prefer $this->expectNotToPerformAssertions(); over assertTrue(true).