## Summary
- Fixed buffer overflow in env_loader when parsing large environment
variables with escape sequences
- Replaced fixed 4096-byte buffer with a stack fallback allocator that
automatically switches to heap allocation for larger values
- Added comprehensive tests to prevent regression
## Background
The env_loader previously used a fixed threadlocal buffer that could
overflow when parsing environment variables containing escape sequences.
This caused crashes when the parsed value exceeded 4KB.
## Changes
- Replaced fixed buffer with `StackFallbackAllocator` that uses 4KB
stack buffer for common cases and falls back to heap for larger values
- Updated all env parsing functions to accept a reusable buffer
parameter
- Added proper memory cleanup with defer statements
## Test plan
- [x] Added test cases for large environment variables with escape
sequences
- [x] Added test for values larger than 4KB
- [x] Added edge case tests (empty quotes, escape at EOF)
- [x] All existing env tests continue to pass
fixes#11627
fixes BAPI-1274
🤖 Generated with [Claude Code](https://claude.ai/code)
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Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
### What does this PR do?
Lets us write and run unit tests directly in Zig.
Running Zig unit tests in CI is blocked by https://github.com/ziglang/zig/issues/23281. We can un-comment relevant code once this is fixed.
#### Workflow
> I'll finish writing this up later, but some initial points are below.
> Tl;Dr: `bun build:test`
Test binaries can be made for any kind of build. They are called `<bun>-test` and live next to their corresponding `bun` bin. For example, debug tests compile to `build/debug/bun-debug-test`.
Test binaries re-use most cmake/zig build steps from normal bun binaries, so building one after a normal bun build is pretty fast.
### How did you verify your code works?
I tested that my tests run tests.
* some work
* linux things
* linux things
* feat: tracestrings on Windows
* bwaa
* more work on the crash handler
* okay
* adgadsgbcxcv
* ya
* dsafds
* a
* wuh
* a
* bru h
* ok
* yay
* window
* alright
* oops
* yeah
* a
* a
* OOM handling
* fix on window
* linter: allow a trailing field
* linter: dont fail if no matches are found
* lint: only import 'bun' once
* lint: ban std.mem.indexOfAny
* linter: ignore commented out code and ignore benchmarks
* this was testing nothing
* lint: ban std.debug.print
* this wasnt testing anything either
* Revert "fix!: do not lookup cwd in which (#9691)"
This reverts commit 4869ebff24.
* fix which implementation to be more accurate
* t
* which tests windows
* [autofix.ci] apply automated fixes
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
