feat: add REFLEX_HOT_RELOAD_OVERRIDE_PATHS to fully override reload paths

[adhami3310]

Summary

Adds a REFLEX_HOT_RELOAD_OVERRIDE_PATHS environment variable (colon-separated list of paths). When set, get_reload_paths() returns these paths directly, taking precedence over REFLEX_HOT_RELOAD_INCLUDE_PATHS, REFLEX_HOT_RELOAD_EXCLUDE_PATHS, and the config-derived defaults.

This gives embedders full control over what the dev-mode file watcher observes — e.g. pointing it at a dedicated control directory instead of relying on the app's project layout.

Linear: ENG-9752

[linear-code]

ENG-9752

[greptile-apps]

Greptile Summary

This PR introduces a REFLEX_HOT_RELOAD_OVERRIDE_PATHS environment variable that, when set, causes get_reload_paths() to return those paths directly, bypassing all config-derived defaults, include paths, and exclude paths.

• Adds the new EnvVar[list[Path]] field to EnvironmentVariables in environment.py, following the same pattern as the existing REFLEX_HOT_RELOAD_INCLUDE_PATHS and REFLEX_HOT_RELOAD_EXCLUDE_PATHS variables.
• Inserts an early-return guard at the top of get_reload_paths() in exec.py that resolves the override paths to absolute paths, emits a debug log, and returns immediately — leaving all existing logic untouched when the variable is unset.

Confidence Score: 5/5

Safe to merge — the change is an additive opt-in feature with no effect when the env var is unset.

The override guard is an isolated early-return that is inert by default (empty list is falsy). The implementation mirrors the existing include/exclude path handling exactly: same Path.absolute conversion, same EnvVar[list[Path]] typing, same debug log pattern. No existing behavior is modified.

No files require special attention.

Important Files Changed

Filename	Overview
reflex/utils/exec.py	Adds override-path early-return at the top of get_reload_paths() with a debug log; falls through to existing logic when env var is unset. Logic is correct and consistent with include/exclude handling.
packages/reflex-base/src/reflex_base/environment.py	Adds REFLEX_HOT_RELOAD_OVERRIDE_PATHS env var as EnvVar[list[Path]] with default [], consistent with the existing include/exclude path variables.
news/6639.feature.md	Changelog entry for the new env var; accurate and complete.
packages/reflex-base/news/6639.feature.md	Secondary changelog entry for the reflex-base package; accurate and concise.

_{Reviews (3): Last reviewed commit: "add changelog fragments" | Re-trigger Greptile}

[codspeed-hq]

Merging this PR will not alter performance

✅ 26 untouched benchmarks
⏩ 8 skipped benchmarks¹

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_{Comparing khaleel/eng-9752-add-reflex_hot_reload_override_paths-env-var-to-fully (faf949f) with main (d486e9b)}

Footnotes

1. 8 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩