Database disk image malformed after system crash

[archaengel]

Describe and demonstrate the bug
I don't think a transcript is applicable here. My machine crashed while I was working on my codebase and attempting to start ucm backup I was greeted with this message

Uh oh, an unexpected exception brought the process down! That should never happen. Please file a bug report.

Here's a stringy rendering of the exception:

  SqliteQueryException {sql = "SELECT version FROM schema_version", params = [], exception = SQLite3 returned ErrorCorrupt while attempting to perform prepare "SELECT version FROM schema_version": database disk image is malformed, callStack = [("throwSqliteQueryException",SrcLoc {srcLocPackage = "unison-sqlite-0.0.0-EM4axGKNyuM52uN6Ok9c4z", srcLocModule = "Unison.Sqlite.Connection", srcLocFile = "src/Unison/Sqlite/Connection.hs", srcLocStartLine = 220, srcLocStartCol = 9, srcLocEndLine = 220, srcLocEndCol = 34}),("queryListRow",SrcLoc {srcLocPackage = "unison-sqlite-0.0.0-EM4axGKNyuM52uN6Ok9c4z", srcLocModule = "Unison.Sqlite.Connection", srcLocFile = "src/Unison/Sqlite/Connection.hs", srcLocStartLine = 283, srcLocStartCol = 9, srcLocEndLine = 283, srcLocEndCol = 21}),("gqueryListCheck",SrcLoc {srcLocPackage = "unison-sqlite-0.0.0-EM4axGKNyuM52uN6Ok9c4z", srcLocModule = "Unison.Sqlite.Connection", srcLocFile = "src/Unison/Sqlite/Connection.hs", srcLocStartLine = 274, srcLocStartCol = 3, srcLocEndLine = 274, srcLocEndCol = 18}),("queryListRowCheck",SrcLoc {srcLocPackage = "unison-sqlite-0.0.0-EM4axGKNyuM52uN6Ok9c4z", srcLocModule = "Unison.Sqlite.Connection", srcLocFile = "src/Unison/Sqlite/Connection.hs", srcLocStartLine = 257, srcLocStartCol = 3, srcLocEndLine = 257, srcLocEndCol = 20}),("queryOneRow",SrcLoc {srcLocPackage = "unison-sqlite-0.0.0-EM4axGKNyuM52uN6Ok9c4z", srcLocModule = "Unison.Sqlite.Connection", srcLocFile = "src/Unison/Sqlite/Connection.hs", srcLocStartLine = 263, srcLocStartCol = 41, srcLocEndLine = 263, srcLocEndCol = 52}),("queryOneCol",SrcLoc {srcLocPackage = "unison-sqlite-0.0.0-EM4axGKNyuM52uN6Ok9c4z", srcLocModule = "Unison.Sqlite.Transaction", srcLocFile = "src/Unison/Sqlite/Transaction.hs", srcLocStartLine = 289, srcLocStartCol = 24, srcLocEndLine = 289, srcLocEndCol = 46}),("queryOneCol",SrcLoc {srcLocPackage = "unison-codebase-sqlite-0.0.0-GO3bVQgu5bqI4cVjIguow2", srcLocModule = "U.Codebase.Sqlite.Queries", srcLocFile = "./U/Codebase/Sqlite/Queries.hs", srcLocStartLine = 491, srcLocStartCol = 3, srcLocEndLine = 491, srcLocEndCol = 14})], connection = Connection { name = "main", file = "/Users/god/.unison/v2/unison.sqlite3" }, threadId = ThreadId 12}

I'm aware there may not be much hope given this happened due to a system crash but reporting here for posterity

Environment (please complete the following information):

• ucm --version unison version: release/0.5.29 (built on 2024-12-02)
• OS/Architecture: macOS 13.6.7, Intel

[archaengel]

I was able to recover the db by running

cd ~/.unison/v2
sqlite3 unison.sqlite3 .recover | sqlite3 unison.sqlite3.recovered
mv unison.sqlite3 unison.sqlite3.corrupted_bak
mv unison.sqlite3.recovered unison.sqlite3

[aryairani]

Wow, that is kind of surprising. I'm not sure if we can do anything about it as it seems like a sqlite issue, but we'll discuss it.

Thanks for reporting and I'm glad you were able to recover your database.