Normalize TDLib fatal log lines before hashing

[FrayxRulez]

When TDLib hits an internal LOG(FATAL) it aborts, and the log line it printed becomes the crash report's message — which is what the backend hashes. Those lines look like this:

[ 0][t 5][crypto.cpp:420][#1][!Session:4:download#0][&res != 1]
[ 0][t 3][crypto.cpp:420][#1][!Session:1:main][&res != 1]
[ 0][t 5][MessageInputReplyTo.cpp:129][#1][!MessagesManager] local message 840.18 in not a topic in chat 0 with flags 0

Everything volatile in them is in the message: the thread number, the scheduler tag, the datacenter index inside the session actor, and the message/chat/file ids and offsets in the trailing text. So one assertion fragments into a group per report, every group looks like a singleton, and the whole class reads as noise.

TryTranslateTdlibLog follows TryTranslateAstaCall: a recogniser that rewrites a line it recognises to a canonical form, and returns the line completely unchanged when it does not match. It matches TDLib's prefix by shape — level, thread, file.ext:line, then any number of context tags — not against a list of known files, so a new assertion normalises without a change here.

What it keeps, because it is the identity of the assertion:

• the source location (crypto.cpp:420),
• the actor name minus its instance index (Session:4:download#0 → Session:download; download is a different code path from main, the 4 is only which datacenter the account is on),
• the stringified condition (`id == 0 || is_server()`, [&res != 1]) verbatim, digits included,
• any second source reference in the free text (UserManager.cpp 4821, DialogDb.cpp at line 170) — Status.h and LogEvent.h are generic helpers whose real site is that trailing reference, and two sites in one file would otherwise merge.

What it drops: the thread and scheduler tags, the actor's instance index, and — the one genuinely arguable call — the numbers and quoted strings left in the free text. Those are the values the assertion happened to print, the file:line above already identifies which assertion failed, and the quoted string is invariably the database path, which carries the user's profile directory into the report.

Checked against every distinct TdException message the dashboard holds for the last 28 days: the rule collapses that set to well under half as many distinct forms, it is idempotent, and it leaves every message of every other error type in that set byte-for-byte unchanged. Note only the first line of a message is hashed, so that is the line this has to get right.

Not built. A .NET Native build was not available; the file was checked with CSharpSyntaxTree.ParseText(...).GetDiagnostics() (clean, so no syntax errors — that catches typos, not type errors), and the four regexes were run as real .NET Regex objects over the message corpus described above, which is what produced the figures.

🤖 Generated with Claude Code