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3571: Introduce two filters to select documents with `null` and empty fields r=irevoire a=Kerollmops # Pull Request ## Related issue This PR implements the `X IS NULL`, `X IS NOT NULL`, `X IS EMPTY`, `X IS NOT EMPTY` filters that [this comment](https://github.com/meilisearch/product/discussions/539#discussioncomment-5115884) is describing in a very detailed manner. ## What does this PR do? ### `IS NULL` and `IS NOT NULL` This PR will be exposed as a prototype for now. Below is the copy/pasted version of a spec that defines this filter. - `IS NULL` matches fields that `EXISTS` AND `= IS NULL` - `IS NOT NULL` matches fields that `NOT EXISTS` OR `!= IS NULL` 1. `{"name": "A", "price": null}` 2. `{"name": "A", "price": 10}` 3. `{"name": "A"}` `price IS NULL` would match 1 `price IS NOT NULL` or `NOT price IS NULL` would match 2,3 `price EXISTS` would match 1, 2 `price NOT EXISTS` or `NOT price EXISTS` would match 3 common query : `(price EXISTS) AND (price IS NOT NULL)` would match 2 ### `IS EMPTY` and `IS NOT EMPTY` - `IS EMPTY` matches Array `[]`, Object `{}`, or String `""` fields that `EXISTS` and are empty - `IS NOT EMPTY` matches fields that `NOT EXISTS` OR are not empty. 1. `{"name": "A", "tags": null}` 2. `{"name": "A", "tags": [null]}` 3. `{"name": "A", "tags": []}` 4. `{"name": "A", "tags": ["hello","world"]}` 5. `{"name": "A", "tags": [""]}` 6. `{"name": "A"}` 7. `{"name": "A", "tags": {}}` 8. `{"name": "A", "tags": {"t1":"v1"}}` 9. `{"name": "A", "tags": {"t1":""}}` 10. `{"name": "A", "tags": ""}` `tags IS EMPTY` would match 3,7,10 `tags IS NOT EMPTY` or `NOT tags IS EMPTY` would match 1,2,4,5,6,8,9 `tags IS NULL` would match 1 `tags IS NOT NULL` or `NOT tags IS NULL` would match 2,3,4,5,6,7,8,9,10 `tags EXISTS` would match 1,2,3,4,5,7,8,9,10 `tags NOT EXISTS` or `NOT tags EXISTS` would match 6 common query : `(tags EXISTS) AND (tags IS NOT NULL) AND (tags IS NOT EMPTY)` would match 2,4,5,8,9 ## What should the reviewer do? - Check that I tested the filters - Check that I deleted the ids of the documents when deleting documents Co-authored-by: Clément Renault <clement@meilisearch.com> Co-authored-by: Kerollmops <clement@meilisearch.com>
Filter parser
This workspace is dedicated to the parsing of the Meilisearch filters.
Most of the code and explanation are in the lib.rs. Especially, the BNF of the filters at the top of this file.
The parser use nom to do most of its work and nom-locate to keep track of what we were doing when we encountered an error.
Cli
A simple main is provided to quick-test if a filter can be parsed or not without bringing milli. It takes one argument and try to parse it.
cargo run -- 'field = value' # success
cargo run -- 'field = "doggo' # error => missing closing delimiter "
Fuzz
The workspace have been fuzzed with cargo-fuzz.
Setup
You'll need rust-nightly to execute the fuzzer.
cargo install cargo-fuzz
Run
When the filter parser is executed by the fuzzer it's triggering a stackoverflow really fast. We can avoid this problem by limiting the max_len of libfuzzer at 500 characters.
cargo fuzz run parse -- -max_len=500
What to do if you find a bug in the parser
- Write a test at the end of the
lib.rsto ensure it never happens again. - Add a file in the corpus directory with your filter to help the fuzzer find new bugs. Since this directory is going to be heavily polluted by the execution of the fuzzer it's in the gitignore and you'll need to force push your new test.