sqlite3_create_collation(..., null) doesn't delete collations

[bricelam]

using System;
using static SQLitePCL.raw;

SQLitePCL.Batteries_V2.Init();

sqlite3_open(":memory:", out var db);

sqlite3_create_collation(db, "DELETE_ME", null, (_, strA, strB) => string.CompareOrdinal(strA, strB));
sqlite3_create_collation(db, "DELETE_ME", null, null);

sqlite3_prepare_v2(db, "select group_concat(name) from pragma_collation_list", out var stmt);
sqlite3_step(stmt);
var collations = sqlite3_column_text(stmt, 0).utf8_to_string();

Console.WriteLine(collations);

The result should not contain DELETE_ME.

I suspect the wrapping hook_handle is preventing it from being deleted.

https://github.com/ericsink/SQLitePCL.raw/blob/1b2e50535cf3c3e4811197b72b7dc694715227f6/src/SQLitePCLRaw.provider.dynamic_cdecl/Generated/provider_dynamic_cdecl.cs#L798-L802

[bricelam]

This might just be a SQLite bug. Versions before 3.31.0 also returned deleted functions.

[ericsink]

I do need to investigate this a bit.

To be clear, you do not appear to be saying that this is something which was previously working and now does not?

[bricelam]

I don’t know if it worked previously. This is my first try and I think I only tried on the latest prerelease of e_sqlite3

[ericsink]

Hmmm.

I went to write a failing test for this and noticed that there is already a test case that verifies a collation gets deleted: test_collation_remove

The code in the test is different, as it verifies the removal by actually trying to use the collation and expecting an error.

So there is something more subtle going on here.

[ericsink]

Wait -- what is pragma_collation_list ? I expected that to be PRAGMA collation_list rather than a SELECT.