[rajmundtoth0]

Summary

Fixes #742

This PR fixes an issue in the PHP agent's cURL auto-instrumentation where setting CURLOPT_CUSTOMREQUEST to null produces an unexpected type validation error.

The issue was encountered in production while downloading files through Laravel's filesystem abstraction, using the AWS SDK and Guzzle.

Problem

CurlHandleTracker::processSetOpt() currently expects CURLOPT_CUSTOMREQUEST to contain a string:

if (!$this->util->verifyIsString($optionValue)) {
    return;
}

However, passing null is valid cURL behavior and clears the custom HTTP method override.

As a result, the agent incorrectly logs:

[ERROR] [Auto-Instrumentation]
Actual type does not match the expected type
{"expected type":"string","actual type":"NULL"}

This creates unnecessary error logs during otherwise valid HTTP operations and can leave the agent with incorrect HTTP method tracking.

Changes

• Allow null as a valid value for CURLOPT_CUSTOMREQUEST.
• Handle resetting the custom HTTP method while preserving correct method tracking.
• Keep existing validation for unexpected types.
• Add regression coverage for setting and clearing custom HTTP methods.

Testing

Regression tests cover:

• Setting a custom HTTP method.
• Resetting CURLOPT_CUSTOMREQUEST to null.
• Correct HTTP method tracking after resetting the override.
• Both curl_setopt() and curl_setopt_array().
• Existing HTTP method handling to prevent regressions.

Motivation

APM instrumentation should observe valid application behavior without introducing misleading errors.

This is a small compatibility fix that improves the reliability and accuracy of cURL instrumentation without requiring changes to applications or their HTTP clients.

[github-actions]

🤖 GitHub comments

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[Copilot]

🟡 Changes recommended

The custom HTTP method override survives curl_reset(), causing the agent to record DELETE when cURL sends POST on a reused handle; tracked options need resetting and regression coverage.

1 open issue

• Reset tracked cURL options when intercepting curl_reset() · New

What changed in this PR

This PR addresses #742 by allowing the PHP agent’s cURL instrumentation to accept CURLOPT_CUSTOMREQUEST = null and track the underlying HTTP method after the override is cleared.

Changes:

• Add nullable-string validation while retaining validation for unexpected types.
• Track custom method overrides separately and use the effective method in span names and HTTP context.
• Add regression tests for both option-setting APIs, method precedence, null resets, and copied handles.

File	Description
tests/​ElasticApmTests/​UnitTests/​CurlAutoInstrumentationUnitTest.php	Adds method-tracking and validation regression tests.
agent/​php/​ElasticApm/​Impl/​AutoInstrument/​Util/​AutoInstrumentationUtil.php	Adds a nullable-string validation helper.
agent/​php/​ElasticApm/​Impl/​AutoInstrument/​CurlHandleTracker.php	Separates custom overrides from underlying methods and preserves them when copying handles.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues were identified for the changes supporting nullable cURL custom methods and tracking method overrides.

No open issues 🎉

1 resolved since last review

• Reset tracked cURL options when intercepting curl_reset()

_{Review effort: Balanced}

[intuibase]

@rajmundtoth0 Thank you for contributing this fix.