TL;DR

Deno 2.9.3 introduces expanded dependency management options and adds support for Windows ARM64 compilation.

New

• Enhanced CLI: Added --no-save and --save-optional flags to deno add, and a --min-dep-age alias for dependency versioning.
• Expanded Compilation: Now supports the aarch64-pc-windows-msvc target (Windows ARM64).
• HTTP2 Control: Added http2MaxHeaderListSize to Deno.createHttpClient for finer network tuning.

Fixes Worth Knowing

• Node.js Compatibility: Resolved several SQLite conversion failures and fixed memory leaks related to Socket/TCPWrap.
• Web Standards: Fixed issues with Event subclasses and encodeInto buffer handling.
• Performance: Optimized randomUUID generation and improved fs.cp (file system copy) speeds.

TL;DR

Deno now provides more informative error messages when symlinking fails and offers clearer guidance during upgrades, including links for Deno 2 Release Candidates (pre-release versions).

Fixes Worth Knowing

Several fixes improve Node.js compatibility, including better support for importing JWK keys (digital key format) and resolving issues with worker threads. Improvements were also made to the formatter to correctly handle markdown and code components. deno install now uses relative symlinks.

Before You Upgrade

No specific action is required for this upgrade.

TL;DR

Deno’s standard library has undergone significant reorganization and instability, and several features have been removed, requiring code adjustments for many users.

Breaking

• Public Rust API for the “deno” crate is removed. (Internal Deno code)
• Standard library modules are reorganized and marked unstable. (May require import changes)
• WebSocket Reader/Writer functionality reverted. (Web development)
• Deno.execPath now requires --allow-read. (System interaction)
• Deno.hostname and Worker namespace are unstable. (Core functionality)
• .wasm imports are no longer supported. (WebAssembly)

New

• Bundle command accepts a --config flag. (Build process)
• Workers now have access to the crypto global. (Secure operations)

Fixes Worth Knowing

• Inspector no longer hangs when task budget is exceeded. (Debugging tool)
• Multiple Set-Cookie headers are now allowed. (Web development)
• Improved error messages for DENO_DIR creation failures. (Environment setup)
• Fixed panic on unsupported import schemes. (Dependency management

TL;DR

Deno underwent significant internal changes in this release, resulting in numerous breaking changes primarily affecting low-level APIs and internal structures. These changes aim to improve stability and prepare the runtime for future features.

Breaking

• “address” renamed to “path” in Unix socket options.
• DirEntry no longer requires extra stat syscalls.
• Argument order changed in Deno.copy() and copyN.
• Return type of Deno.resources() changed.
• Deno.chdir() now requires --allow-write permission.
• Several APIs (like Deno.listenDatagram, Deno.dir, Deno.kill) are now unstable. (Unstable APIs may change without notice.)
• Conn.closeRead removed.
• Deno.EOF removed; use null instead.
• Deno.OpenMode removed.
• Deno.runTests() API removed.
• Deno.symbols namespace removed.
• Combined io interfaces (like ReadCloser) removed.
• `Deno.to