clang-tidy: modernize-use-using

[bneradt]

Legacy typedef declarations obscure complex aliases and preserve C-era
declaration patterns in ATS and its plugins. This patch replaces the
existing findings with named C++ declarations or using aliases and enables
the check in CI to keep new code consistent.

[Copilot]

🟡 Changes recommended

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Pull request overview

This PR modernizes legacy typedef declarations across ATS core headers and multiple plugins by replacing them with using aliases or named struct/enum declarations, and enables modernize-use-using in the clang-tidy CI configuration to prevent regressions.

Changes:

• Convert typedef struct patterns to using aliases or named struct declarations in several plugins and internal headers.
• Convert typedef enum patterns to named enum declarations in multiple plugin sources and a session-sharing SDK header.
• Enable modernize-use-using in .clang-tidy-ci.

File summaries

File	Description
plugins/remap_purge/remap_purge.cc	Replaces a typedef struct alias with a using+struct form for the purge instance type.
plugins/regex_revalidate/regex_revalidate.cc	Modernizes typedef struct into using+struct for invalidate list/state types.
plugins/lua/ts_lua.cc	Converts a typedef struct into a named struct for Lua plugin stats.
plugins/lua/ts_lua_stat.cc	Converts typedef enum into named enum declarations for Lua stat constants.
plugins/lua/ts_lua_remap.cc	Converts typedef enum into a named enum for remap status mapping.
plugins/lua/ts_lua_package.cc	Converts a typedef struct into a named struct for package path entries.
plugins/lua/ts_lua_http.cc	Converts typedef enum into named enum declarations for Lua HTTP constants.
plugins/lua/ts_lua_http_txn_info.cc	Converts typedef enum into a named enum for txn info key mapping.
plugins/lua/ts_lua_http_milestone.cc	Converts typedef enum into a named enum for milestone mapping.
plugins/lua/ts_lua_http_config.cc	Converts typedef enum into named enum declarations for config/timeouts.
plugins/lua/ts_lua_http_cntl.cc	Converts typedef enum into a named enum for HTTP control mapping.
plugins/lua/ts_lua_hook.cc	Converts typedef enum into a named enum for hook ID mapping.
plugins/lua/ts_lua_fetch.h	Converts fetch-related typedef struct types into named struct / using forms.
plugins/lua/ts_lua_coroutine.h	Converts function pointer typedef and several typedef struct types into using/named struct forms.
plugins/lua/ts_lua_common.h	Converts multiple typedef struct declarations into named struct types used throughout the Lua plugin.
plugins/lua/ts_lua_client_request.cc	Converts typedef enum into a named enum for PP info keys.
plugins/libloader/libloader.cc	Converts a typedef struct alias into a using+struct form for link handles.
plugins/healthchecks/healthchecks.cc	Converts a typedef struct alias into a using+struct form for directory entries.
include/tscore/ink_queue.h	Converts a conditional typedef pair to using in the 128-bit CAS branch.
include/iocore/net/SessionSharingAPIEnums.h	Converts SDK-facing typedef enum declarations into named enum declarations.
include/iocore/net/NetVConnection.h	Converts a typedef enum into a named enum for net VC context.
include/iocore/eventsystem/VConnection.h	Converts an opaque-pointer typedef to a using alias.
.clang-tidy-ci	Enables the modernize-use-using clang-tidy check in CI.

Review details

Suppressed comments (2)

include/iocore/net/SessionSharingAPIEnums.h:51

• Same C-compatibility issue as above: add a C-only typedef after this enum so C plugins can continue to use TSServerSessionSharingMatchMask without prefixing enum.

};

include/iocore/net/SessionSharingAPIEnums.h:59

• Same C-compatibility issue as above: add a C-only typedef after this enum so C plugins can continue to use TSServerSessionSharingPoolType without prefixing enum.

};

• Files reviewed: 23/23 changed files
• Comments generated: 2
• Review effort level: Lite

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[Copilot]

🟢 Approval recommended

Review details

• Files reviewed: 23/23 changed files
• Comments generated: 0 new
• Review effort level: Lite

[cmcfarlen]

Strange mix of adding using and renaming structs in this PR. We should just name the struct imo.

[Copilot]

🟢 Approval recommended

The changes are mechanical, preserve existing semantics in the reviewed contexts, and the CI enforcement aligns with the stated goal of preventing new legacy typedef patterns.

Review details

• Files reviewed: 23/23 changed files
• Comments generated: 0 new
• Review effort level: Lite