---
id: "bug-1599"
status: "fixed"
status_updated: "2026-09-24"
status_note: "sim_loop.c comment reworded"
component: "scheduler"
severity: "unknown"
timestamp: "2026-08-20T02:50:00Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 1
files: ["src/scheduler/testsuite/test_no_bare_printf.c (new regression test) flags src/scheduler/src/sim_loop.c"]
tags: ["scheduler", "test-only", "false-positive", "sim_loop.c", "test_no_bare_printf", "text-scan", "regression-test"]
related: []
legacy: true
---

# bug-1599: sched_no_bare_printf_test / test_scheduler_src_has_no_bare_printf_calls FAIL…

## Description
sched_no_bare_printf_test / test_scheduler_src_has_no_bare_printf_calls FAIL: '.../scheduler/src/sim_loop.c calls bare printf() -- xce_scheduler link-wraps printf ...' -- even though sim_print_decision() in sim_loop.c already correctly uses fprintf(stdout, ...) for all 3 PEND/DISPATCH/PREEMPT lines (verified via grep: lines 398/402/406 all fprintf(stdout, ...), zero bare printf( calls in actual code).

## Environment
_Not recorded (migrated from buglog.json)._

## Reproduction
_Not recorded (migrated from buglog.json)._

## Root cause
The new regression test's scan_dir_for_bare_printf()/contains_bare_printf_call() (test_no_bare_printf.c) is a naive whole-file text scan with NO comment/string-literal awareness (documented as such in its own header comment, matching test_core_isolation.c's precedent). The doc comment directly above sim_print_decision() in sim_loop.c (lines 375-387, added as part of this same fix, explaining WHY fprintf(stdout,...) is used instead of printf()) contains the literal prose substrings ' plain printf() (2026-08-20 fix)' (line 375) and ' plain printf() call' (line 377) -- both have a space immediately before 'printf(', which the scanner's rule (char before 'printf(' must not be letter/digit/underscore) matches as a bare-printf violation. The scanner cannot distinguish prose describing printf() from an actual call to it.

## Fix
NOT YET FIXED -- reported to caller for triage per explicit instruction not to fix. Likely fix: reword the sim_loop.c doc comment (lines 375/377) to avoid the literal pattern '<space>printf(' immediately -- e.g. write it as "printf" and "(" separately, or reference the wrapped __wrap_printf() symbol name instead of the bare word, or otherwise break up the substring so the naive scanner does not match it. Do NOT weaken the scanner itself to add comment-awareness without considering that test_core_isolation.c deliberately uses the same simple/strict genre.

## Verification
_Not recorded (migrated from buglog.json)._

## References
_Not recorded (migrated from buglog.json)._