fix: keep emoji escape tail bounded

[liuq19]

Summary

• stop emoji escaping at the end of a truncated or invalid UTF-8 tail
• add an ASAN-backed regression test for the bounded-input case
• authenticate same-repository pull request coverage uploads with Codecov OIDC while preserving tokenless uploads for forks

Root cause

When fewer than four bytes remained, DoEscape copied one raw byte and used continue. That skipped the nb == 0 termination check, allowing the loop to read beyond the input and eventually underflow the remaining length.

Scope

• include/sonic/internal/arch/common/quote_common.h
• tests/quote_test.cpp
• .github/workflows/test_coverage.yml

No public API changes. The unrelated JSONPath, header self-containment, and broader CI changes from the earlier revision were removed.

Validation

• regression test on the old implementation reproduced an AddressSanitizer heap-buffer-overflow
• ASAN_OPTIONS=detect_leaks=0 ./build/tests/unittest '--gtest_filter=Quote.*' --gtest_brief=1 — 3/3 passed
• ASAN_OPTIONS=detect_leaks=0 ./build/tests/unittest --gtest_brief=1 — 303/303 passed
• git diff --check origin/master...HEAD
• actionlint .github/workflows/test_coverage.yml
• GitHub Actions Test Coverage run 29555640052 — passed, including the Codecov OIDC upload

[github-actions]

Benchmark

Mode: informational
Warning threshold: >3% regression
Critical threshold: >10% regression
Included benchmarks: Sonic

Severity	Benchmark	base real_time	head real_time	delta
warning	gsoc-2018/Decode_SonicDyn	815850.33 ns	840928.79 ns	+3.07%
warning	gsoc-2018/Encode_SonicDyn	559328.12 ns	590324.40 ns	+5.54%
info	lottie/Stat_SonicDyn	197180.82 ns	189035.25 ns	-4.13%
warning	poet/Encode_SonicDyn	630690.54 ns	661932.44 ns	+4.95%

Overall severity: warning

Conclusion: informational only. Benchmark regressions are reported in this summary/artifact and do not block the workflow.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 69.67%. Comparing base (966f9d5) to head (f8d8094).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #142   +/-   ##
=======================================
  Coverage   69.67%   69.67%           
=======================================
  Files          27       27           
  Lines        3706     3706           
  Branches     1189     1189           
=======================================
  Hits         2582     2582           
  Misses        211      211           
  Partials      913      913           

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[Copilot]

Pull request overview

Fixes a bounds bug in the scalar quote/escape path when kSerializeEscapeEmoji is enabled and the remaining input tail is shorter than 4 bytes, preventing out-of-bounds reads/length underflow. Adds a regression test to exercise the bounded-input tail case under ASAN.

Changes:

• Adjust DoEscape control flow so the nb == 0 termination check is not skipped for short (<4 bytes) tails in emoji-escape mode.
• Add a unit test that validates emoji escaping stops at the end of an invalid/truncated UTF-8 tail without over-reading.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
include/sonic/internal/arch/common/quote_common.h	Fixes DoEscape loop control to keep the remaining-length check effective when fewer than 4 bytes remain.
tests/quote_test.cpp	Adds an ASAN-friendly regression test covering the short invalid tail case for kSerializeEscapeEmoji.

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[yangzhg]

LGTM