Add support for seq_no_primary_term search option and if_seq_no/if_primary_term index options

[ruflin]

Summary

This PR adds support for Elasticsearch's seq_no_primary_term search option and enhances index operations with if_seq_no and if_primary_term options for optimistic concurrency control.

Changes

Search Options

• Added OPTION_SEQ_NO_PRIMARY_TERM constant to Search class
• Added validation for the new option in Search::validateOption()
• This allows retrieving sequence numbers and primary terms in search results

Index Operations

• Added if_seq_no and if_primary_term to allowed options in Index::addDocument()
• These options were already supported in AbstractUpdateAction but weren't being passed through
• Enables proper optimistic concurrency control for document operations

Testing

• Added SearchSeqNoPrimaryTermTest.php with comprehensive tests for the search option
• Added IndexSeqNoPrimaryTermTest.php with tests for optimistic concurrency control
• All tests follow Elastica's testing patterns and include both unit and functional tests

Documentation

• Updated CHANGELOG.md with the new features

Benefits

1. Optimistic Concurrency Control: Users can now implement proper optimistic concurrency control using sequence numbers and primary terms
2. Search Result Metadata: The seq_no_primary_term option allows retrieving sequence numbers and primary terms from search results
3. Backward Compatibility: All changes are additive and don't break existing functionality
4. Elasticsearch 9.x Compatible: The implementation works with the current supported Elasticsearch version

Related Issues

Resolves #2232

Testing

• All existing tests pass
• New tests cover the added functionality
• Code follows Elastica's coding standards
• No breaking changes introduced

Example Usage

// Search with seq_no_primary_term
$search = new Search($client);
$search->addIndex($index);
$search->setOption(Search::OPTION_SEQ_NO_PRIMARY_TERM, true);
$resultSet = $search->search();

// Optimistic concurrency control
$doc = new Document('1', ['title' => 'Updated']);
$doc->setSequenceNumber($retrievedSeqNo);
$doc->setPrimaryTerm($retrievedPrimaryTerm);
$index->addDocument($doc);

[Copilot]

Pull Request Overview

This PR adds support for Elasticsearch's optimistic concurrency control features by implementing seq_no_primary_term search option and if_seq_no/if_primary_term index options.

• Adds OPTION_SEQ_NO_PRIMARY_TERM constant to enable retrieval of sequence numbers and primary terms in search results
• Extends Index::addDocument() to support if_seq_no and if_primary_term options for optimistic concurrency control
• Includes comprehensive test coverage for both search and index functionality

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Search.php	Adds OPTION_SEQ_NO_PRIMARY_TERM constant and validation for the new search option
src/Index.php	Adds if_seq_no and if_primary_term to allowed options in addDocument() method
tests/SearchSeqNoPrimaryTermTest.php	Comprehensive test coverage for the new search option functionality
tests/IndexSeqNoPrimaryTermTest.php	Test coverage for optimistic concurrency control in index operations
CHANGELOG.md	Documents the new features added in this release

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