Allow steam to run with fex by adding override options

[utkarshdalal]

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Summary by cubic

Add FEX AppConfig overrides so Steam and its helper processes run correctly under FEX. Overrides are created at startup and applied during X server setup.

• New Features
  • Auto-write FEX AppConfig JSON overrides for Steam and common helper executables.
  • Apply overrides during X server setup via FEXCoreManager.ensureAppConfigOverrides().
  • Stop deleting FEX config files on container creation to preserve overrides.

^{Written for commit e37f75d. Summary will update on new commits.}

Summary by CodeRabbit

• Refactor
  • Apply per-executable app configuration overrides during environment setup to ensure consistent runtime settings.
  • Stop removing existing config files when preparing containers, preserving user/app configuration data.
  • Improve detection and handling of target executables to reliably apply configuration overrides across environments.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Added per-executable FEX app-config overrides via new FEXCoreManager APIs and invoked them during X environment setup; removed explicit deletion of FEXCore config files from container utilities.

Changes

Cohort / File(s)	Summary
FEXCoreManager — new config APIs app/src/main/java/com/winlator/fexcore/FEXCoreManager.java	Added APP_CONFIG_EXE_NAMES and APP_CONFIG_CONTENT constants, plus ensureAppConfigOverrides(Context) (writes per-exe JSON files) and findAppConfigExeName(String) (case-insensitive exe name matcher).
X environment integration app/src/main/java/app/gamenative/ui/screen/xserver/XServerScreen.kt	Call to FEXCoreManager.ensureAppConfigOverrides(context) inserted within setupXEnvironment after guestProgramLauncherComponent is added.
Container utilities cleanup app/src/main/java/app/gamenative/utils/ContainerUtils.kt	Removed explicit calls that deleted FEXCore config files during container retrieval/creation to keep per-app config files intact.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Only use FEX env vars and not config.json #334: Related edits to FEXCoreManager and container config handling—overlaps with deleted-config logic and new override behavior.
• Fix versions changing #224: Adds/changes FEXCoreManager helpers for FEXCore settings; likely touches the same config-management area.
• Stop anrs #238: Modifies XServerScreen environment setup where the new ensureAppConfigOverrides call was added.

Poem

🐰
I hopped through folders, nibbling bugs away,
Left config files safe so apps can play,
Wrote tiny JSON notes for each exe,
Planted overrides where they should be,
Now games wake up and dance — hip-hip-hooray! 🎉

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: adding FEX AppConfig overrides to enable Steam execution, which aligns with the core functionality added across the modified files.

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✨ Finishing touches

• 📝 Generate docstrings

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@app/src/main/java/com/winlator/fexcore/FEXCoreManager.java`:
- Around line 50-67: ensureAppConfigOverrides is writing AppConfig into
"/home/xuser/.config/.fex-emu/AppConfig" while deleteConfigFiles targets
"imagefs/home/xuser/.fex-emu/AppConfig", so align the two: update
ensureAppConfigOverrides (and/or deleteConfigFiles) to derive the same baseDir
from ImageFs.find(context).getRootDir() and use a single canonical path for the
FEX config (e.g., include or omit the ".config" segment consistently), or
extract a shared helper that constructs the baseDir used by both
ensureAppConfigOverrides and deleteConfigFiles so
APP_CONFIG_EXE_NAMES/APP_CONFIG_CONTENT files are created and deleted from the
identical directory.

🧹 Nitpick comments (1)

app/src/main/java/com/winlator/fexcore/FEXCoreManager.java (1)

69-78: Remove unused method findAppConfigExeName.

This method is not called anywhere in the codebase and should be removed to reduce code clutter.

[cubic-dev-ai]

No issues found across 3 files

[cubic-dev-ai]

No issues found across 3 files