Disable SDK from autoloading during composer execution.

[ChrisLightfootWild]

Proposal to prevent the SDK from auto-loading during composer script execution.

During a composer script, the packaged dependencies in the composer.phar are currently locked to PSR-3 v2 and thus any local application dependencies which expect v3 can trigger a fatal error.

By preventing the SdkAutoloader from being auto-loaded, we can hopefully avoid the fatal error from triggering.

Fixes #1673.

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To test, we can perform the following actions:

make update PHP_VERSION=8.3

make bash PHP_VERSION=8.3

OTEL_PHP_AUTOLOAD_ENABLED=true composer run-script test-psr3

Before:

> OpenTelemetry\Tests\Integration\Composer\Psr3CompatabilityTest::run

Fatal error: Declaration of Psr\Log\AbstractLogger::emergency(Stringable|string $message, array $context = []): void must be compatible with Psr\Log\LoggerInterface::emergency($message, array $context = []) in /usr/src/myapp/vendor/psr/log/src/LoggerTrait.php on line 18

echo $?
255

After:

> OpenTelemetry\Tests\Integration\Composer\Psr3CompatabilityTest::run

echo $?
0

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.32%. Comparing base (ddb222d) to head (9ec2a8c).

Files with missing lines	Patch %	Lines
src/SDK/_autoload.php	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1727      +/-   ##
============================================
- Coverage     68.37%   68.32%   -0.05%     
  Complexity     2971     2971              
============================================
  Files           448      448              
  Lines          9020     9021       +1     
============================================
- Hits           6167     6164       -3     
- Misses         2853     2857       +4     

Flag	Coverage Δ
8.1	68.06% <0.00%> (+<0.01%)	⬆️
8.2	68.30% <0.00%> (+0.05%)	⬆️
8.3	68.30% <0.00%> (+0.08%)	⬆️
8.4	68.21% <0.00%> (-0.03%)	⬇️
8.5	68.16% <0.00%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/SDK/_autoload.php	0.00% <0.00%> (ø)

... and 4 files with indirect coverage changes

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[brettmc]

What would happen if you were starting your application through a composer script? eg something like composer run-my-application ?

[ChrisLightfootWild]

Previously, if you were using a compatible version of psr/log then the SDK would bootstrap.

If you were using an incompatible version, it would cause a fatal exception.

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With the proposed changes, the SDK is essentially disabled.