Conn Man crashed twice in an Owens on 2026-07-27, kept playing, and by the time
we asked for his logs they no longer existed. Not a mystery: every launcher did
if exist content\X.old.log del content\X.old.log
if exist content\X.log ren content\X.log X.old.log
which keeps TWO generations. He relaunched more than twice, so his own bat
deleted both crash sessions. The player who crashes is exactly the player who
relaunches immediately, so the retention window was aimed at the wrong case.
THE LOG. BT_LOG set still means "use this path verbatim" -- that contract is
load-bearing (mp_a.log/mp_b.log for 2-node runs from one cwd, btoperator's
operator_N.log, every scratchpad/mp_*.sh that greps the file it named) and is
untouched. Only when BT_LOG is UNSET does the exe now name the file itself:
content\<stem>_YYYYMMDD.log, appended, one per day, no rotation window to fall
out of. The stem (solo/join/steam/joyconfig) comes from the gates the bat
already sets, so solo still cannot overwrite the MULTIPLAYER log.
Self-named files append UNCONDITIONALLY. The default open mode is ios::out --
TRUNCATE -- and the operator GUI's exported bats never set BT_LOG_APPEND, so
they were truncating already; leaving append implicit would have let the second
launch of the day erase the morning.
IDENTITY, because these arrive from many players at once and Discord renames
half of them to message.txt (most of the night-5 evidence had to be
re-identified by hand):
===== BT411 SESSION build=4.11.603 (d64d75f+) machine=... user=...
callsign=Conn Man mode=solo pid=13192 local=... log=... =====
Also the session separator inside a per-day file, and it puts build+hash ABOVE
any [crash] block so btl4+0xNNNN offsets stay matchable to a PDB across builds.
SIZE. Never delete, but stay sendable: past 8 MB the next launch rolls to
<stem>_YYYYMMDD.1.log. Checked only at open, so a live session is never split.
CONSOLIDATION. launch_report.txt is gone, folded into lastrun_<stem>.txt (one
launch record: the exe appends its block at first breath, the bat appends the
exit line). Per-stem because one shared lastrun.txt let a second launcher's
`del` destroy the first launch's block. Its ABSENCE after a run is now the
#41 "never reached WinMain" probe -- the old "if not exist X.log" test cannot
work against a per-day file, which survives earlier launches, and would have
reported every healthy run as blocked by antivirus. marshal.log folded into
the day log too; it keeps its own handle and gained a CRITICAL_SECTION because
it runs on a worker thread while the engine log stream is single-threaded.
play_steam.bat gained a launch bracket it never had -- which is why a Steam
player killed before WinMain previously left no evidence at all.
_putenv_s, not SetEnvironmentVariableA, to pin the resolved name: MSVC's CRT
keeps its own environment copy, so getenv() in-process does NOT see a
SetEnvironmentVariableA write (measured). btl4console/btl4lobby resolve the
day log via getenv, so with the Win32-only call they silently fell back to
marshal.log and the fold never happened.
logfile.open() is now checked -- a failed open used to rebind cout to a dead
buffer, silently dropping the header, [boot] and any crash stack while
lastrun still claimed log=<name>.
Verified: append across sessions with distinct pids, crash block landing under
its own header, BT_LOG verbatim unmangled, an inherited BT_LOG cleared by the
bats, roll-over at 8 MB, and both forensic verdicts (exe ran / exe blocked).
Console auto-retrieval is unaffected -- it uploads the matchlog, a different
file, and a crashed round never reaches the upload call anyway.
Known gaps, deliberately not in this commit: the setlocal hoist for gate
leakage when two bats share one console (dev-only), and btoperator's exported
bats still lack the lastrun bracket -- do not press Export on a shipped zip.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
