fix(sandbox): preserve zero exit code in E2B JSON stream

[ump45nose]

AgentScope-Java Version

2.0.1-SNAPSHOT

Description

Fixes #2603.

In E2bCodec.JSON mode, an explicit {"end":{"exitCode":0}} frame was lost twice because proto3 does not include default scalar values in getAllFields() and reports no scalar presence through hasField(). As a result, successful commands kept the missing-exit sentinel and failed.

This change:

• attaches the JSON end event when an integer exitCode was explicitly parsed, including zero;
• reads the proto3 default scalar from the present end event instead of checking scalar presence;
• adds a focused regression test for a zero exit code.

Related duplicate reports: #2601, #2602.

Tested with:

mvn -pl agentscope-extensions/agentscope-extensions-sandbox/agentscope-extensions-sandbox-e2b -am -Dtest=E2bEnvdProcessClientTest -Dsurefire.failIfNoSpecifiedTests=false test

Result: 8 tests passed, including jsonCodecPreservesZeroExitCode.

Checklist

Please check the following items before code is ready to be reviewed.

• Code has been formatted with mvn spotless:apply
• All targeted tests are passing
• Javadoc comments are complete and follow project conventions (no public API changes)
• Related documentation has been updated (not applicable; behavior fix with regression coverage)
• Code is ready for review

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...e/extensions/sandbox/e2b/E2bEnvdProcessClient.java	0.00%	0 Missing and 1 partial ⚠️

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[AgentScopeJavaBot]

🤖 AI Review

This PR fixes a proto3 default-value bug where an exitCode of 0 was silently dropped in the E2B JSON codec path. Root cause: DynamicMessage.hasField() returns false for proto3 non-optional scalar fields set to their default value, and getAllFields() omits default-valued fields. The fix is minimal, correct, and directly addresses issue #2603. A focused regression test is included. This also benefits the proto codec path where a binary-encoded EndEvent with exit_code=0 would also be missed.

[AgentScopeJavaBot]

🤖 AI Review

This PR fixes a proto3 default-value bug where an exitCode of 0 was silently dropped in the E2B JSON codec path. Root cause: DynamicMessage.hasField() returns false for proto3 non-optional scalar fields set to their default value, and getAllFields() omits default-valued fields. The fix is minimal, correct, and directly addresses issue #2603. A focused regression test is included. This also benefits the proto codec path where a binary-encoded EndEvent with exit_code=0 would also be missed.