Skip deep type-validation on state var hot paths

[Alek99]

Linear: ENG-10093

Description

Two hot paths ran _isinstance(value, type, nested=1), which walks every element of list/dict values, only to gate a diagnostic log that never changes behavior:

• BaseState.__setattr__ validated the full container on every assignment.
• ComputedVar.__get__ / AsyncComputedVar.__get__ validated the return type on every access, including cache hits.

Changes:

• Computed var return types are now validated only when the value is actually recomputed (sync and async). Cache hits skip the check entirely.
• Element-wise validation depth is now 1 in dev and 0 in prod (new cached _validation_depth() helper in reflex_base.utils.types), so production only checks the outer type. Dev keeps the exact same diagnostics as before.

Benchmarks (GitHub Actions runner, run, 2 passes each)

Case	main	this PR	speedup
read cached computed var returning 10k dicts (dev)	13.81 / 14.05 ms	0.0015 / 0.0015 ms	~9,200x
read cached computed var (prod)	13.66 / 13.93 ms	0.0013 / 0.0015 ms	~9,300x
assign 100k-int list (prod)	90.89 / 90.96 ms	0.020 / 0.024 ms	~4,000x
assign 100k-int list (dev)	90.74 / 92.67 ms	91.76 / 94.74 ms	unchanged (by design)

cProfile (3 assigns + 20 cached reads, dev): main spends 3.06s in 10.5M calls dominated by _isinstance (510k calls); with this PR the cached-read side disappears (_check_deprecated_return_type no longer on the cache-hit path) and in prod the whole workload is 538 function calls / 0.003s.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Changes To Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
  • tests/units/reflex_base/vars/test_base.py: return type checked on recompute, not on cache hits (sync, async, and cache=False).
  • tests/units/reflex_base/utils/test_types.py: _validation_depth() is 0 in prod / 1 in dev.
  • tests/units/test_state.py: wrong-typed assignment still logs an error in dev.
• Have you successfully ran tests with your changes locally?

Note: behavior-wise, a wrong-typed computed var now logs once per recompute instead of once per access, and prod no longer walks container elements for the log-only check. No exceptions or control flow depend on these checks.

🤖 Generated with Claude Code

https://claude.ai/code/session_01G8cXh3TUbNtbjm2ERqE62X

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Generated by Claude Code

[linear-code]

ENG-10093

[greptile-apps]

Greptile Summary

This PR reduces type-validation work on state hot paths. The main changes are:

• Adds a validation-depth helper based on REFLEX_ENV_MODE.
• Uses shallow container checks in production diagnostics.
• Validates computed-var return types on recompute instead of cache hits.
• Adds unit coverage for mode changes, assignments, and computed vars.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• The environment mode change now flows through os.environ values that match the validation helper.
• The new imports add symbols from modules that were already imported on these paths.

Important Files Changed

Filename	Overview
packages/reflex-base/src/reflex_base/utils/types.py	Adds env-aware validation-depth helpers that re-read REFLEX_ENV_MODE on each call.
packages/reflex-base/src/reflex_base/vars/base.py	Moves computed-var return validation to recompute paths and uses the new validation depth.
reflex/state.py	Uses the new validation depth for state assignment diagnostics.
tests/units/reflex_base/utils/test_types.py	Covers production-to-development validation-depth changes without manual cache clearing.
tests/units/reflex_base/vars/test_base.py	Covers sync, async, cached, and non-cached computed-var validation behavior.
tests/units/test_state.py	Covers wrong-typed state assignment diagnostics.

_{Reviews (3): Last reviewed commit: "Honor runtime env mode changes in _valid..." | Re-trigger Greptile}

[codspeed-hq]

Merging this PR will not alter performance

✅ 26 untouched benchmarks
⏩ 8 skipped benchmarks¹

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_{Comparing claude/reflex-perf-optimizations-01l7a3-eng-10093 (f75dcde) with main (9a5c4d3)}

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. ↩