fix: remove dead serialize_dict call in format_prop

[masenf]

Requested by Masen · project thread

Before: format_prop({"a": 1}) raised AttributeError: module 'reflex_base.utils.serializers' has no attribute 'serialize_dict'. The dict branch in format_prop called a serializer that no longer exists, hidden behind a pyright-ignore.

After: a plain dict is JSON-encoded like every other literal and wrapped in braces, so format_prop({"a": 1}) returns {{"a": 1}}.

The branch was unreachable from inside the framework, since every internal caller passes a Var or EventChain and returns earlier; only direct callers with a raw dict hit it.

How: drop the isinstance(prop, dict) branch and the unused serializers import so dicts fall through to json_dumps, which already encodes nested values through the registered serializers. Adds a regression test and a reflex-base news fragment.

Closes ENG-10109.

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?
• Have you successfully ran tests with your changes locally?

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Generated by Claude Code

[linear-code]

ENG-10109

[cubic-dev-ai]

No issues found across 3 files

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[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge.

Summary

Fixes format_prop for plain dictionaries by removing the call to the missing serialize_dict function.

• Plain dictionaries now format as JSON props wrapped in braces.

_{Reviews (1) · Last reviewed commit: "fix: remove dead serialize_dict call in ..." · Reviewed by Greptile}

[codspeed]

Merging this PR will not alter performance

⚠️ 17 benchmarks spent significant time in system calls

System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• test_get_state[memory]
• test_get_state[disk]
• test_cli_startup[run_help]
• test_cli_startup[deploy_help]
• test_cli_startup[cloud_help]
• test_cli_startup[version]
• test_cli_startup[help]
• test_import_reflex
• test_set_state[disk]
• test_state_manager_memory_read_only_modify
• …and 7 more

✅ 148 untouched benchmarks

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_{Comparing claude/project-thread-8w0spl (d5e3eb2) with main (5ae5dcd)}