PubSub implementation

[jduo]

• Support subscribe, unsubscribe, psubscribe, and punsubscribe in standalone and cluster clients. Partition callback lookup by client type.
• Allow multiple clients with their own callbacks. Each client has one callback that can be overwritten with another subscribe call. Unsubscribing is not required.
• Cleanup callbacks on subscribe. Use atomic-reference counting and validation flags to avoid race conditions where a callback is invoked during destruction, unsubscription, or callback overwriting without blocking.

Issue link

This Pull Request is linked to issue (URL): [REPLACE ME]

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one issue.
• Commit message has a detailed description of what changed and why.
• Tests are added or updated.
• CHANGELOG.md and documentation files are updated.
• Destination branch is correct - main or release
• Create merge commit if merging release branch into main, squash otherwise.

[Copilot]

Pull Request Overview

This pull request implements PubSub (Publish/Subscribe) functionality for Valkey GLIDE, supporting both standalone and cluster clients with safe callback management and reference counting to prevent race conditions during callback lifecycle operations.

Key changes:

• Added subscribe, unsubscribe, psubscribe, and punsubscribe commands with callback support
• Implemented separate callback registries for standalone and cluster clients to prevent cross-client callback invocation
• Introduced atomic reference counting with validation flags for thread-safe callback management during destruction and overwriting

Reviewed Changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
valkey_glide_pubsub.h	Header file defining PubSub structures, callback wrappers, and method macros
valkey_glide_pubsub.c	Core PubSub implementation with callback management and command execution
valkey_glide_core_commands.c	Updated client creation to register PubSub callbacks and client mappings
valkey_glide_commands_common.h	Modified function signatures to include valkey_glide_object parameter
valkey_glide_cluster.stub.php	Uncommented PubSub method declarations for cluster client
valkey_glide_cluster.c	Implemented PubSub methods using macros for cluster client
valkey_glide.stub.php	Added comprehensive PubSub method documentation and signatures
valkey_glide.c	Implemented PubSub methods and callback cleanup in destructor
tests/ValkeyGlideTest.php	Added extensive test coverage for PubSub functionality
tests/ValkeyGlideBatchTest.php	Added test to verify PubSub commands are blocked in batch mode
config.m4	Added valkey_glide_pubsub.c to build configuration
common.h	Added pubsub_callback and is_cluster_client fields to valkey_glide_object
README.md	Added PubSub usage documentation and examples

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[Copilot]

The documentation indicates the parameter accepts array|string, but the C implementation (valkey_glide_pubsub.c line 339) only accepts arrays with Z_PARAM_ARRAY. This inconsistency between documentation and implementation will cause runtime errors when users pass strings.

[Copilot]

The documentation indicates the parameter accepts array|string, but the C implementation (valkey_glide_pubsub.c line 374) only accepts arrays with Z_PARAM_ARRAY. This inconsistency between documentation and implementation will cause runtime errors when users pass strings.

[Copilot]

The documentation indicates the parameter accepts array|string, but the C implementation (valkey_glide_pubsub.c line 410) only accepts arrays or null with Z_PARAM_ARRAY_OR_NULL. This inconsistency between documentation and implementation will cause runtime errors when users pass strings.

[Copilot]

The callback signature shows 3 parameters, but according to the test at line 7582 in ValkeyGlideTest.php, the actual callback receives the redis instance as the first parameter. The documentation should clarify that $redis is the ValkeyGlide client instance, not a generic 'redis' reference.

[Copilot]

The callback signature documentation conflicts with the test at line 7675 and actual implementation at line 142-143 in valkey_glide_pubsub.c. The actual callback receives parameters in order: $redis, $channel, $message, $pattern (with pattern as 4th arg), not $redis, $pattern, $channel, $message as documented.

Suggested change

	* @param callable $callback Callback function to handle messages: function($redis, $pattern, $channel, $message)
	* @param callable $callback Callback function to handle messages: function($redis, $channel, $message, $pattern)

[Copilot]

Pull Request Overview

Copilot reviewed 15 out of 15 changed files in this pull request and generated 9 comments.

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