When a document deletion occurs, instead of deleting the document we mark it as deleted
in the new “soft deleted” bitmap. It is then removed from the search, and all the other
endpoints.
291: Fix a bug about zero bytes in the inputs r=irevoire a=Kerollmops
Ok, good news, after a little session of debugging with `@irevoire` we found out that the bug seems to be related to zeroes in the input update. The engine wasn't designed to accept those. The chosen solution is to update the tokenizer to remove those zeroes. We are waiting on https://github.com/meilisearch/tokenizer/pull/52 to be merged and a new version to be released.
It is not an undefined behavior, I repeat: it is a "normal" bug 🎉👏
----
This PR tries to fix a bug where we use LMDB in the wrong way, leading to panic due to an undefined behavior on the Rust side. I thought [we fixed it in a previous PR](https://github.com/meilisearch/milli/pull/264) but we found out that _a similar_ bug was still present. `@bb` found a way to trigger this bug and helped us find the origin of it.
As I don't have a minimal reproducible example of this bug I bet on the unsafe `put_current` calls when we index new documents as the bug was trigger after a big indexation on a clean database, thus not triggering a deletion update. I only replaced the unsafe `put_current` with two safe calls to `get`/`put`.
I hope it helps and fixes the bug, only `@bb` can help us check that. I am not even sure how I can create a custom Docker image and expose it for testing purposes.
<details>
<summary>The backtrace leading us to a panic in grenad.</summary>
```
meilisearch_1 | thread 'tokio-runtime-worker' panicked at 'assertion failed: key > &last_key', /root/.cargo/git/checkouts/grenad-e2cb77f65d31bb02/3adcb26/src/block_builder.rs:38:17
meilisearch_1 | stack backtrace:
meilisearch_1 | 0: rust_begin_unwind
meilisearch_1 | at ./rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:493:5
meilisearch_1 | 1: core::panicking::panic_fmt
meilisearch_1 | at ./rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/core/src/panicking.rs:92:14
meilisearch_1 | 2: core::panicking::panic
meilisearch_1 | at ./rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/core/src/panicking.rs:50:5
meilisearch_1 | 3: grenad::block_builder::BlockBuilder::insert
meilisearch_1 | at ./root/.cargo/git/checkouts/grenad-e2cb77f65d31bb02/3adcb26/src/block_builder.rs:38:17
meilisearch_1 | 4: grenad::writer::Writer<W>::insert
meilisearch_1 | at ./root/.cargo/git/checkouts/grenad-e2cb77f65d31bb02/3adcb26/src/writer.rs:92:12
meilisearch_1 | 5: milli::update::words_level_positions::write_level_entry
meilisearch_1 | at ./root/.cargo/git/checkouts/milli-00376cd5db949a15/007fec2/milli/src/update/words_level_positions.rs:262:5
meilisearch_1 | 6: milli::update::words_level_positions::compute_positions_levels
meilisearch_1 | at ./root/.cargo/git/checkouts/milli-00376cd5db949a15/007fec2/milli/src/update/words_level_positions.rs:211:13
meilisearch_1 | 7: milli::update::words_level_positions::WordsLevelPositions::execute
meilisearch_1 | at ./root/.cargo/git/checkouts/milli-00376cd5db949a15/007fec2/milli/src/update/words_level_positions.rs:65:23
meilisearch_1 | 8: milli::update::index_documents::IndexDocuments::execute_raw
meilisearch_1 | at ./root/.cargo/git/checkouts/milli-00376cd5db949a15/007fec2/milli/src/update/index_documents/mod.rs:831:9
meilisearch_1 | 9: milli::update::index_documents::IndexDocuments::execute
meilisearch_1 | at ./root/.cargo/git/checkouts/milli-00376cd5db949a15/007fec2/milli/src/update/index_documents/mod.rs:372:9
meilisearch_1 | 10: meilisearch_http::index::updates::<impl meilisearch_http::index::Index>::update_documents_txn
meilisearch_1 | at ./meilisearch/meilisearch-http/src/index/updates.rs:225:30
meilisearch_1 | 11: meilisearch_http::index::updates::<impl meilisearch_http::index::Index>::update_documents
meilisearch_1 | at ./meilisearch/meilisearch-http/src/index/updates.rs:183:22
meilisearch_1 | 12: meilisearch_http::index::update_handler::UpdateHandler::handle_update
meilisearch_1 | at ./meilisearch/meilisearch-http/src/index/update_handler.rs:75:18
meilisearch_1 | 13: meilisearch_http::index_controller::index_actor::actor::IndexActor<S>::handle_update::{{closure}}::{{closure}}
meilisearch_1 | at ./meilisearch/meilisearch-http/src/index_controller/index_actor/actor.rs:174:35
meilisearch_1 | 14: <tokio::runtime::blocking::task::BlockingTask<T> as core::future::future::Future>::poll
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/blocking/task.rs:42:21
meilisearch_1 | 15: tokio::runtime::task::core::CoreStage<T>::poll::{{closure}}
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/task/core.rs:243:17
meilisearch_1 | 16: tokio::loom::std::unsafe_cell::UnsafeCell<T>::with_mut
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/loom/std/unsafe_cell.rs:14:9
meilisearch_1 | 17: tokio::runtime::task::core::CoreStage<T>::poll
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/task/core.rs:233:13
meilisearch_1 | 18: tokio::runtime::task::harness::poll_future::{{closure}}
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/task/harness.rs:427:23
meilisearch_1 | 19: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
meilisearch_1 | at ./rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panic.rs:344:9
meilisearch_1 | 20: std::panicking::try::do_call
meilisearch_1 | at ./rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:379:40
meilisearch_1 | 21: std::panicking::try
meilisearch_1 | at ./rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:343:19
meilisearch_1 | 22: std::panic::catch_unwind
meilisearch_1 | at ./rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panic.rs:431:14
meilisearch_1 | 23: tokio::runtime::task::harness::poll_future
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/task/harness.rs:414:19
meilisearch_1 | 24: tokio::runtime::task::harness::Harness<T,S>::poll_inner
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/task/harness.rs:89:9
meilisearch_1 | 25: tokio::runtime::task::harness::Harness<T,S>::poll
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/task/harness.rs:59:15
meilisearch_1 | 26: tokio::runtime::task::raw::RawTask::poll
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/task/raw.rs:66:18
meilisearch_1 | 27: tokio::runtime::task::Notified<S>::run
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/task/mod.rs:171:9
meilisearch_1 | 28: tokio::runtime::blocking::pool::Inner::run
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/blocking/pool.rs:265:17
meilisearch_1 | 29: tokio::runtime::blocking::pool::Spawner::spawn_thread::{{closure}}
meilisearch_1 | at ./root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.7.1/src/runtime/blocking/pool.rs:245:17
meilisearch_1 | note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
```
</details>
Co-authored-by: Kerollmops <clement@meilisearch.com>
It is undefined behavior to keep a reference to the database while
modifying it, we were keeping references in the database and also
feeding the heed put_current methods with keys referenced inside
the database itself.
https://github.com/Kerollmops/heed/pull/108
