HybridCompile: Exit after Arduino project SCons run

[Jason2866]

Description:

Related issue (if applicable): fixes #496

Checklist:

• The pull request is done against the latest develop branch
• Only relevant files were touched
• Only one feature/fix was added per PR, more changes are allowed when changing boards.json
• I accept the CLA

[Jason2866]

@coderabbitai analyze if this PR fixes #496

[coderabbitai]

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@Jason2866: Yes, PR #498 directly and completely addresses issue #496. Here's the breakdown:

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Issue #496 — Root Cause Recap

When custom_sdkconfig triggers the Arduino hybrid-compile flow, espidf.py spawns a child pio run subprocess that performs the full Arduino build. After the child returns, the outer SCons process was continuing into its own build pipeline — but the outer env is only partially configured (missing FLASH_EXTRA_IMAGES entries like boot_app0.bin and user CPPDEFINES from build_flags). This caused:

1. Post-action scripts (e.g., reading BUILD_FLAGS) to crash when invoked a second time in the broken outer env.
2. firmware.factory.bin to be silently overwritten with an incomplete version (no boot_app0.bin).
3. Doubled build time due to the outer env re-linking and re-running esptool steps.

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What PR #498 Changes

# Before
env.Execute(
    env.VerboseAction(...)
)

# After
child_rc = env.Execute(        # ← capture child exit code
    env.VerboseAction(...)
)

# Added after the optional component_manager.restore_pioarduino_build_py():
env.Exit(child_rc if child_rc else 0)

---

Analysis

Issue impact	Fixed by PR #498?	How
Post-action scripts crash in outer env	✅ Yes	env.Exit() stops outer SCons before it re-runs post-actions
firmware.factory.bin corrupted (missing boot_app0.bin)	✅ Yes	Outer SCons never reaches the esptool step
Doubled build time	✅ Yes	Outer SCons exits immediately after child completes

Key design points:

• env.Exit(child_rc if child_rc else 0) correctly propagates failure: if the child pio run fails (non-zero), the outer process also exits with that code, so build failures are not swallowed.
• The exit is placed after component_manager.restore_pioarduino_build_py(), so the cleanup step still executes before the outer process stops.
• The fix is scoped only to the hybrid-compile path — it does not affect normal (non-hybrid) builds.

The implementation is exactly what the issue author suggested ("After env.Execute(...), call env.Exit(0) or sys.exit(child_rc)"), and covers all reported failure modes. ✅