fix: bound JSON output shutdown after interrupt by harsh21234i · Pull Request #7578 · reflex-dev/reflex

harsh21234i · 2026-10-15T13:57:25Z

Summary

Bound shutdown after the first interrupt, including while output is being drained.
Isolate the POSIX child process group so Ctrl-C is forwarded exactly once.
Keep shutdown handlers active through drain and ignore repeated signals.
Bound oversized JSON records to the pipe's atomic-write limit so every emitted line remains parseable.
Add regression coverage for repeated Ctrl-C/SIGTERM, oversized records, drain cleanup, and forced test-process cleanup.
Add the Reflex Base bugfix news fragment.

Tests

tests/units/reflex_base/utils/test_log.py: 81 passed, 5 skipped on Windows (POSIX-only cases).
Linux Docker smoke tests: group SIGINT forwarded once; oversized output stayed valid JSON; blocked drain remained bounded after a second SIGTERM.
Ruff formatting, focused lint, and git diff --check passed.

Fixes #7510

greptile-apps · 2026-10-15T14:03:23Z

Confidence Score: 4/5

[Medium impact] Fixes JSON output shutdown when interrupted.

Fix the nested-JSON output-thread failure before merging.

Findings

Nested logs stop output ▶

Summary

This PR bounds JSON-output shutdown from the first interrupt.

Interrupts start a bounded shutdown and reach the child group once.
Oversized JSON records stay parseable and fit pipe limits.

Both numbered previous findings are fixed. The new recursive truncation can stop an output thread on deeply nested JSON.

_{Reviews (3) · Last reviewed commit: "fix: preserve fields in oversized log re..." · Reviewed by Greptile}

codspeed · 2026-10-15T14:06:40Z

Merging this PR will not alter performance

⚠️

21 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_cli_startup[run_help]

test_get_state[disk]

test_import_cli

test_cli_startup[deploy_help]

test_event_future_tree

test_state_manager_memory_warm_get

test_state_manager_memory_read_only_modify

test_yield_intermediate_update

test_modify_state[disk]

…and 11 more

✅ 148 untouched benchmarks

_{Comparing harsh21234i:fix/7510-bounded-json-drain (e7f0078) with main (7ccaa4e)}

cubic-dev-ai

All reported issues were addressed across 3 files

_{Reply with feedback, questions, or to request a fix.

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cubic-dev-ai

All reported issues were addressed

_{Reply with feedback, questions, or to request a fix.

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cubic-dev-ai

All reported issues were addressed across 3 files (changes from recent commits).

_{Reply with feedback, questions, or to request a fix.

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greptile-apps · 2026-10-15T14:47:09Z

+        if isinstance(value, dict):
+            return {
+                key: truncate_strings(item, max_chars) for key, item in value.items()
+            }
+        if isinstance(value, list):
+            return [truncate_strings(item, max_chars) for item in value]


Nested logs stop output

On supported Python 3.11, an oversized JSON record with roughly 600 nested containers can pass json.loads but fail inside truncate_strings. Each level adds both a function call and a comprehension frame, exhausting the allowed call depth sooner.

The resulting RecursionError escapes _write, which only catches OSError, and stops the output thread. Later child output can fill the unread pipe and hang the command. Use a walk that does not recurse, or catch this failure and emit a bounded fallback record.

cubic-dev-ai

3 issues found across 2 files (changes from recent commits).

Prompt for AI agents (unresolved issues)


Check if these issues are valid — if so, understand the root cause of each and fix them. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="packages/reflex-base/src/reflex_base/utils/log.py">

<violation number="1" location="packages/reflex-base/src/reflex_base/utils/log.py:426">
P1: Replace this recursive traversal with an iterative walk so deeply nested JSON records cannot raise `RecursionError` and terminate the output pump.</violation>

<violation number="2" location="packages/reflex-base/src/reflex_base/utils/log.py:434">
P2: A near-limit record dominated by non-string fields can trigger thousands of full copies and serializations before reaching the fallback, stalling output draining. Detect when retries cannot shrink the record or cap the retry work.</violation>

<violation number="3" location="packages/reflex-base/src/reflex_base/utils/log.py:435">
P2: Oversized records containing `NaN` or `Infinity` are emitted as non-standard JSON because this serialization uses the default `allow_nan=True`. Normalize non-finite values before dumping so strict JSON consumers can parse every emitted line.</violation>
</file>

_{Reply with feedback, questions, or to request a fix.

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cubic-dev-ai · 2026-10-15T14:53:11Z

+            return value if len(value) <= max_chars else value[:max_chars] + marker
+        if isinstance(value, dict):
+            return {
+                key: truncate_strings(item, max_chars) for key, item in value.items()


P1: Replace this recursive traversal with an iterative walk so deeply nested JSON records cannot raise RecursionError and terminate the output pump.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. At packages/reflex-base/src/reflex_base/utils/log.py, line 426: <comment>Replace this recursive traversal with an iterative walk so deeply nested JSON records cannot raise `RecursionError` and terminate the output pump.</comment> <file context> @@ -416,32 +416,30 @@ def _truncate_json_record(record: bytes, max_bytes: int) -> bytes: + return value if len(value) <= max_chars else value[:max_chars] + marker + if isinstance(value, dict): + return { + key: truncate_strings(item, max_chars) for key, item in value.items() + } + if isinstance(value, list): </file context>

cubic-dev-ai · 2026-10-15T14:53:11Z

+
+    payload["truncated"] = True
+    max_chars = max_bytes
+    while True:


P2: A near-limit record dominated by non-string fields can trigger thousands of full copies and serializations before reaching the fallback, stalling output draining. Detect when retries cannot shrink the record or cap the retry work.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. At packages/reflex-base/src/reflex_base/utils/log.py, line 434: <comment>A near-limit record dominated by non-string fields can trigger thousands of full copies and serializations before reaching the fallback, stalling output draining. Detect when retries cannot shrink the record or cap the retry work.</comment> <file context> @@ -416,32 +416,30 @@ def _truncate_json_record(record: bytes, max_bytes: int) -> bytes: + + payload["truncated"] = True + max_chars = max_bytes + while True: + result = json.dumps(truncate_strings(payload, max_chars)).encode() + b"\n" + if len(result) <= max_bytes: </file context>

cubic-dev-ai · 2026-10-15T14:53:11Z

+    payload["truncated"] = True
+    max_chars = max_bytes
+    while True:
+        result = json.dumps(truncate_strings(payload, max_chars)).encode() + b"\n"


P2: Oversized records containing NaN or Infinity are emitted as non-standard JSON because this serialization uses the default allow_nan=True. Normalize non-finite values before dumping so strict JSON consumers can parse every emitted line.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. At packages/reflex-base/src/reflex_base/utils/log.py, line 435: <comment>Oversized records containing `NaN` or `Infinity` are emitted as non-standard JSON because this serialization uses the default `allow_nan=True`. Normalize non-finite values before dumping so strict JSON consumers can parse every emitted line.</comment> <file context> @@ -416,32 +416,30 @@ def _truncate_json_record(record: bytes, max_bytes: int) -> bytes: + payload["truncated"] = True + max_chars = max_bytes + while True: + result = json.dumps(truncate_strings(payload, max_chars)).encode() + b"\n" + if len(result) <= max_bytes: + return result </file context>

fix: bound JSON output shutdown after interrupt

cdbf267

harsh21234i requested a review from a team as a code owner October 15, 2026 13:57

fix: annotate shutdown signal frame

2fedb45

greptile-apps Bot reviewed Oct 15, 2026

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Comment thread packages/reflex-base/src/reflex_base/utils/log.py Outdated

Comment thread packages/reflex-base/src/reflex_base/utils/log.py

Comment thread packages/reflex-base/src/reflex_base/utils/log.py

Comment thread tests/units/reflex_base/utils/test_log.py Outdated

cubic-dev-ai Bot reviewed Oct 15, 2026

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Comment thread packages/reflex-base/src/reflex_base/utils/log.py Outdated

harsh21234i added 2 commits October 15, 2026 19:49

fix: harden supervised output shutdown

7da1021

test: guard supervisor drain against repeated interrupts

27d4e5e

greptile-apps Bot reviewed Oct 15, 2026

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Comment thread packages/reflex-base/src/reflex_base/utils/log.py Outdated

Comment thread tests/units/reflex_base/utils/test_log.py

cubic-dev-ai Bot reviewed Oct 15, 2026

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Comment thread tests/units/reflex_base/utils/test_log.py

fix: preserve fields in oversized log records

e7f0078

greptile-apps Bot reviewed Oct 15, 2026

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cubic-dev-ai Bot reviewed Oct 15, 2026

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Tests

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Confidence Score: 4/5

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codspeed Bot commented Oct 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Merging this PR will not alter performance

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