A user changes nickname on IRC.
Nothing dramatic should happen. The same connection is still alive, the same person is still present, and an authenticated session should simply follow the new nickname.
Yet during the final bug hunt on Mediabot v3, that ordinary IRC event revealed a subtle authentication lifecycle problem: the user changed identity on the network, but the bot’s session registry remained attached to the old nickname.
The result was a small ghost hiding in the castle walls — an authentication session that could survive after the user had apparently left.
MB377 removes that ghost.
The fresh development snapshot already passed the recent regression perimeter:
PASSED: 513/513
That was reassuring, but a green suite is not a reason to stop looking.
The final review focused on lifecycle transitions: places where an object remains valid but changes its public identity. IRC nickname changes are exactly that kind of transition.
MB372 had previously improved authentication by indexing live sessions under the user’s current IRC nickname. That made login, logout and disconnect handling more precise.
However, one transition was still missing:
NICK old_nick → new_nick
The IRC event handler updated the visible nickname in normal channel bookkeeping, but the authentication session itself stayed under the old key.
The broken sequence looked like this:
OldNick logs in
→ authenticated session stored as oldnick
OldNick changes nickname to NewNick
→ IRC now knows NewNick
→ authentication registry still knows oldnick
NewNick leaves IRC
→ logout("NewNick") finds no matching session
→ oldnick remains in the registry
The session was not merely cosmetic.
If the new nickname later triggered another authenticated command, Mediabot could reconstruct or create a second live entry under the new nickname while the stale old entry remained behind.
When the new entry eventually closed, the old ghost session could still make the account appear active and prevent the final cleanup from clearing persistent authentication state.
The direct reproduction before the fix showed the problem clearly:
before=1 old=1
logout_new=0 after=1 logged=1
In plain English:
A user had left the room, but their enchanted portrait was still answering roll call.
A nickname change is not a logout.
It must not:
auth=0;It must only move the live session identity from one nickname to another.
MB377 introduces a dedicated operation:
rename_session($old_nick, $new_nick, hostmask => $new_fullmask)
The method performs the migration as one controlled lifecycle operation.
It:
The real on_message_NICK handler now invokes this migration before continuing its normal nickname bookkeeping.
The person remains the same.
Only the label on the potion bottle changes.
The migration occurs while the IRC connection is still active.
That is important because a nickname change must not be treated like a disconnect followed by a new login.
The corrected flow is:
authenticated OldNick
→ receive NICK NewNick
→ move the existing session to NewNick
→ preserve authenticated state
→ later QUIT/PART/KICK can find NewNick
→ close the real final session
→ clear USER.auth when appropriate
This restores the intended relationship between:
IRC nickname comparisons are often case-insensitive, but the visible nickname still matters.
A transition such as:
Te[u]K → Te[U]K
may resolve to the same normalized lookup key while still changing the nickname presented by the network.
MB377 updates the stored visible session data in that case as well.
The lookup remains stable, while diagnostics and runtime state reflect the current nickname rather than an older spelling.
Not every NICK event belongs to an authenticated user.
The new migration method therefore treats a missing source session as a harmless no-op.
It does not:
The correction is intentionally narrow: authenticated sessions are migrated; all other nickname changes continue normally.
MB377 adds:
t/cases/596_mb377_auth_nick_session_rekey.t
The test verifies the full lifecycle, not merely the presence of a new method.
It checks that:
NICK handler passes the updated hostmask.The historical MB372 authentication lifecycle suite was run alongside the new test.
Results:
MB372 historical coverage : 46/46
MB377 new coverage : 27/27
Targeted total : 73/73
No old authentication behavior had to be weakened to make the new transition work.
Mediabot/Auth.pm
mediabot.pl
t/cases/596_mb377_auth_nick_session_rekey.t
The implementation remains focused:
None.
0 new tables
0 altered columns
0 migrations
0 schema changes
MB377 changes in-memory session lifecycle behavior and event handling only.
The database is touched later only through the normal final-session logout path, exactly where it should be.
The live check is pleasantly simple:
/nick Te[u]K_mb377
m whoami
/nick Te[u]K
m whoami
Both commands must recognize the same authenticated user without requiring another login.
The logs should show session migration rather than a logout/login cycle:
Auth session renamed Te[u]K -> Te[u]K_mb377
Auth session renamed Te[u]K_mb377 -> Te[u]K
There should be no uncaught exception and no unexpected authentication reset.
The final bug hunt also identified a few subjects that deserve their own rounds rather than being smuggled into MB377.
Some report sections are protected by eval, but the DBI handles use:
RaiseError => 0
A failed prepare() or execute() may therefore return false without throwing an exception. Some SQL failures could remain too quiet even though report sections are now isolated.
That requires a dedicated diagnostic pass.
Recent HailoChatter work changed the ratio representation from the historical inverted meaning to a direct percentage.
Existing channel values and the historical default require an explicit compatibility decision. An automatic reinterpretation could make a quiet bot suddenly speak far too often.
No silent migration will be made without deciding the desired behavior first.
Generated test artefacts were also visible in the snapshot, including temporary script directories and a generated reference SQL file.
They are not runtime bugs, but they belong in a separate cleanup pass rather than an authentication commit.
MB377 fixes the kind of bug that is easy to miss because every individual operation appears reasonable:
The failure existed in the space between those operations.
Authentication now follows the live IRC identity across nickname changes, remains stable while the connection survives, and closes correctly when the user finally leaves.
No duplicated session.
No stale account state.
No ghost wandering the corridors under an abandoned nickname.
The Marauder’s Map now knows exactly who is still in the castle.
— Teuk
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