Update runtime language from Zig to Rust in README#30923
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WalkthroughREADME.md updated to clarify that Bun's core runtime is written in Zig rather than Rust in the "What is Bun?" section description. ChangesRuntime Language Documentation
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Verify each finding against current code. Fix only still-valid issues, skip the
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Inline comments:
In `@README.md`:
- Line 29: The README contains an incorrect statement saying "It's written in
Rust" about the Bun runtime (the sentence starting "At its core is the _Bun
runtime_, ... It's written in Rust"); update that sentence to correctly state
"It's written in Zig" so the implementation language matches the project and
other docs.
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Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
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README.md
| Bun is an all-in-one toolkit for JavaScript and TypeScript apps. It ships as a single executable called `bun`. | ||
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| At its core is the _Bun runtime_, a fast JavaScript runtime designed as **a drop-in replacement for Node.js**. It's written in Zig and powered by JavaScriptCore under the hood, dramatically reducing startup times and memory usage. | ||
| At its core is the _Bun runtime_, a fast JavaScript runtime designed as **a drop-in replacement for Node.js**. It's written in Rust and powered by JavaScriptCore under the hood, dramatically reducing startup times and memory usage. |
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🧩 Analysis chain
🏁 Script executed:
#!/bin/bash
# Check for Zig source files and build configuration
echo "=== Checking for Zig source files ==="
fd -e zig -t f | head -20
echo -e "\n=== Checking for Zig build files ==="
fd 'build.zig' -t f
echo -e "\n=== Checking for Rust source files ==="
fd -e rs -t f | head -20
echo -e "\n=== Checking for Rust build files ==="
fd 'Cargo.toml' -t f
echo -e "\n=== Checking src directory structure ==="
fd -t d '^src$' --max-depth 2 -x sh -c 'echo "Directory: {}"; ls -la {} | head -10'
echo -e "\n=== Checking build configuration mentions ==="
rg -i "language.*zig|written.*zig" --type md -C 2Repository: oven-sh/bun
Length of output: 7167
🌐 Web query:
What programming language is Bun written in?
💡 Result:
Bun is primarily written in Zig, a modern, high-performance systems programming language [1][2][3]. While Zig serves as the core language for the runtime and transpiler [1], the project also incorporates other languages and components to support its functionality [4]: - Zig: Used for the main runtime and transpiler implementation [1][2]. - C++ and C: Used for bindings, particularly for the JavaScriptCore engine (developed by Apple) and various low-level libraries like WebSocket implementations [5][4][6]. - JavaScript and TypeScript: Used for internal modules and built-in functionality within the runtime [4][6]. By utilizing Zig, Bun achieves low-level memory control and performance optimizations [3], while leveraging the established JavaScriptCore engine for executing JavaScript code [1][2].
Citations:
- 1: https://bun.com/docs/runtime
- 2: https://yougo-plus.com/en/what-is-bun/
- 3: https://medium.com/code-crafters/what-is-bun-a-high-performance-javascript-runtime-3aaff50aeef7
- 4: https://en.wikipedia.org/wiki/Bun_(software)
- 5: https://news.ycombinator.com/item?id=37246747
- 6: https://github.com/oven-sh/bun/blob/main/src/js/README.md
Revert this change: Bun is written in Zig, not Rust.
The claim that Bun is "written in Rust" is factually incorrect. Official Bun documentation and the codebase confirm that the core runtime and transpiler are primarily implemented in Zig. This statement appears elsewhere correctly in the repository (e.g., packages/bun-vscode/README.md states "It's written in Zig"). Reverting this line to accurately reflect Zig as the implementation language is required.
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@README.md` at line 29, The README contains an incorrect statement saying
"It's written in Rust" about the Bun runtime (the sentence starting "At its core
is the _Bun runtime_, ... It's written in Rust"); update that sentence to
correctly state "It's written in Zig" so the implementation language matches the
project and other docs.
1 participant
What does this PR do?
Update runtime language from Zig to Rust in README