Merge #668

668: Fix many Clippy errors part 2 r=ManyTheFish a=ehiggs

This brings us a step closer to enforcing clippy on each build.

# Pull Request

## Related issue
This does not fix any issue outright, but it is a second round of fixes for clippy after https://github.com/meilisearch/milli/pull/665. This should contribute to fixing https://github.com/meilisearch/milli/pull/659.

## What does this PR do?

Satisfies many issues for clippy. The complaints are mostly:

* Passing reference where a variable is already a reference.
* Using clone where a struct already implements `Copy`
* Using `ok_or_else` when it is a closure that returns a value instead of using the closure to call function (hence we use `ok_or`)
* Unambiguous lifetimes don't need names, so we can just use `'_`
* Using `return` when it is not needed as we are on the last expression of a function.

## PR checklist
Please check if your PR fulfills the following requirements:
- [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [x] Have you read the contributing guidelines?
- [x] Have you made sure that the title is accurate and descriptive of the changes?

Thank you so much for contributing to Meilisearch!


Co-authored-by: Ewan Higgs <ewan.higgs@gmail.com>

milli/src/update/index_documents/enrich.rs

@@ -140,7 +140,7 @@ fn fetch_or_generate_document_id(
                 }
                 None => Ok(Err(UserError::MissingDocumentId {
                     primary_key: primary_key.to_string(),
-                    document: obkv_to_object(&document, &documents_batch_index)?,
+                    document: obkv_to_object(document, documents_batch_index)?,
                 })),
             }
         }
@@ -156,7 +156,7 @@ fn fetch_or_generate_document_id(
                         if matching_documents_ids.len() >= 2 {
                             return Ok(Err(UserError::TooManyDocumentIds {
                                 primary_key: nested.name().to_string(),
-                                document: obkv_to_object(&document, &documents_batch_index)?,
+                                document: obkv_to_object(document, documents_batch_index)?,
                             }));
                         }
                     }
@@ -170,7 +170,7 @@ fn fetch_or_generate_document_id(
                 },
                 None => Ok(Err(UserError::MissingDocumentId {
                     primary_key: nested.name().to_string(),
-                    document: obkv_to_object(&document, &documents_batch_index)?,
+                    document: obkv_to_object(document, documents_batch_index)?,
                 })),
             }
         }
@@ -313,7 +313,7 @@ pub fn validate_document_id_value(document_id: Value) -> Result<StdResult<String
             None => Ok(Err(UserError::InvalidDocumentId { document_id: Value::String(string) })),
         },
         Value::Number(number) if number.is_i64() => Ok(Ok(number.to_string())),
-        content => Ok(Err(UserError::InvalidDocumentId { document_id: content.clone() })),
+        content => Ok(Err(UserError::InvalidDocumentId { document_id: content })),
     }
 }
 

milli/src/update/index_documents/extract/extract_docid_word_positions.rs

@@ -132,7 +132,7 @@ fn json_to_string<'a>(value: &'a Value, buffer: &'a mut String) -> Option<&'a st
     }
 
     if let Value::String(string) = value {
-        Some(&string)
+        Some(string)
     } else if inner(value, buffer) {
         Some(buffer)
     } else {

milli/src/update/index_documents/extract/extract_fid_docid_facet_values.rs

@@ -67,7 +67,7 @@ pub fn extract_fid_docid_facet_values<R: io::Read + io::Seek>(
                 facet_exists_docids.entry(field_id).or_default().insert(document);
 
                 // For the other extraction tasks, prefix the key with the field_id and the document_id
-                key_buffer.extend_from_slice(&docid_bytes);
+                key_buffer.extend_from_slice(docid_bytes);
 
                 let value =
                     serde_json::from_slice(field_bytes).map_err(InternalError::SerdeJson)?;
@@ -107,8 +107,8 @@ pub fn extract_fid_docid_facet_values<R: io::Read + io::Seek>(
     let facet_exists_docids_reader = writer_into_reader(facet_exists_docids_writer)?;
 
     Ok((
-        sorter_into_reader(fid_docid_facet_numbers_sorter, indexer.clone())?,
-        sorter_into_reader(fid_docid_facet_strings_sorter, indexer.clone())?,
+        sorter_into_reader(fid_docid_facet_numbers_sorter, indexer)?,
+        sorter_into_reader(fid_docid_facet_strings_sorter, indexer)?,
         facet_exists_docids_reader,
     ))
 }

milli/src/update/index_documents/extract/mod.rs

@@ -150,7 +150,7 @@ pub(crate) fn data_from_obkv_documents(
     spawn_extraction_task::<_, _, Vec<grenad::Reader<File>>>(
         docid_fid_facet_numbers_chunks,
         indexer,
-        lmdb_writer_sx.clone(),
+        lmdb_writer_sx,
         extract_facet_number_docids,
         merge_cbo_roaring_bitmaps,
         TypedChunk::FieldIdFacetNumberDocids,