Reuse cached file handles with MachOKit backing identities

[p-x9]

Summary

• Update MachOKit to 0.52.0.
• Key mapped-file caches by MachOKit's backing file-handle identity so related MachOFile and DyldCache wrappers reuse the same cached handle.
• Reuse FullDyldCache.urls when opening concatenated cache files instead of resolving the subcache URLs again.

Why

The caches were keyed by individual wrapper objects. Multiple wrappers backed by the same MachOKit file handle could therefore create separate mapped-file cache entries and reopen the same file.

Using MachOKit's backing identity aligns the cache lifetime and reuse boundary with the underlying handle while keeping the identity itself separate from filesystem path identity.

Impact

This reduces redundant file opens and mappings for related MachOKit wrappers. There are no public API changes in MachOObjCSection.

Validation

• git diff --cached --check
• swift test completed the build and the tests observed before interruption passed. The full suite was stopped because existing dump tests emit extremely large Objective-C output and run for an extended period.

[Copilot]

Pull request overview

Updates MachOKit/swift-fileio and adjusts mapped-file caching so multiple MachOKit wrapper objects that share the same underlying backing identity reuse the same cached MemoryMappedFile/ConcatenatedMemoryMappedFile handles, reducing redundant opens/mappings.

Changes:

• Bump MachOKit to 0.52.0 and swift-fileio to 0.14.0 (plus updated lockfiles).
• Key mapped-file caches by MachOKit fileHandleIdentity (SPI) instead of wrapper object identity for MachOFile / DyldCache / FullDyldCache.
• Reuse FullDyldCache.urls when opening concatenated cache files.

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
Sources/MachOObjCSection/Extension/MachOFile+.swift	Switch MemoryMappedFile cache key to MachOKit backing identity.
Sources/MachOObjCSection/Extension/DyldCache+.swift	Introduce shared FileHandleHolder keyed by FileHandleIdentity for dyld cache mappings.
Sources/MachOObjCSection/Extension/FullDyldCache+.swift	Key concatenated-cache mapping by backing identity and reuse urls list.
Package.swift	Update dependency minimum versions (MachOKit, swift-fileio).
Package.resolved	Refresh resolved graph for updated dependencies.
Benchmarks/Package.resolved	Refresh benchmark resolved graph for updated dependencies.

Comments suppressed due to low confidence (1)

Sources/MachOObjCSection/Extension/MachOFile+.swift:26

• This change is performance/behavioral (cache key now uses MachOKit’s fileHandleIdentity). There are existing XCTest suites, but there’s no assertion that two wrappers sharing the same backing identity actually reuse the same MemoryMappedFile instance. Adding a focused unit test would help prevent regressions (e.g., XCTAssertTrue(a.fileHandle === b.fileHandle) for two wrappers known to share identity).

    var fileHandle: File {
        FileHandleHolder.shared.fileHandle(
            for: fileHandleIdentity,
            initialize: {
                try! .open(url: url, isWritable: false)
            }
        )

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