fix(cli): skip mkdir when --out-file targets the current directory

[kdy1]

When --out-file file.min.js is used without a directory component, Path::parent() returns an empty string. Calling create_dir_all("") fails on Windows with EEXIST. Skip the directory creation when the parent path is empty.

Closes #11717

Generated with Claude Code

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[changeset-bot]

⚠️ No Changeset found

Latest commit: b3c1f62

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[claude]

PR Review

Summary

Clean, well-scoped fix for --out-file file.min.js (no directory component) failing on Windows because Path::parent() returns "" and create_dir_all("") errors with EEXIST.

Code Quality

The fix is correct and minimal. Both call sites where parent() is used for directory creation are patched consistently — emit_output (line 244) and CompileOptions (line 480). The as_os_str().is_empty() check is the idiomatic way to detect this edge case in Rust.

Potential Issues

None identified. The guard correctly short-circuits before create_dir_all when the parent is empty (i.e., the file targets the current directory), and the subsequent File::create / fs::write calls work fine with bare filenames.

Minor Observation

In emit_output (line 244), the two conditions are combined in one if:

if !output_dir.as_os_str().is_empty() && !output_dir.is_dir() {

While in the second site (line 480), only the empty check is used:

if !parent.as_os_str().is_empty() {
    fs::create_dir_all(parent)?;
}

The second site unconditionally calls create_dir_all when parent is non-empty, even if the directory already exists. This is fine since create_dir_all is a no-op for existing directories, but the patterns are slightly inconsistent. Not a bug — just a style note. The first site's !is_dir() check avoids a syscall, which is a minor optimization.

Performance

No concerns. The added as_os_str().is_empty() check is essentially free (no allocation, no syscall).

Security

No concerns.

Test Coverage

Good — the new test issue_11717_out_file_same_directory covers the exact failure case: compiling with --out-file file.min.js (no directory component) and asserting it succeeds. The test verifies both that the command exits successfully and that the output contains expected content.

One suggestion: consider also testing the --out-dir path (the emit_output function) with a relative filename to cover both patched sites, though the risk is low since the emit_output path constructs the output path differently via resolve_output_file_path.

Verdict

LGTM — clean fix, well-tested, addresses a real cross-platform issue.

[Copilot]

Pull request overview

Fixes a Windows-specific CLI failure when --out-file is given without a directory component (e.g. file.min.js), where the computed parent path can be empty and create_dir_all("") fails.

Changes:

• Skip directory creation when the computed parent path is empty for --out-file and --out-dir output paths.
• Add a regression test covering --out-file file.min.js written to the current directory (issue #11717).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
crates/swc_cli_impl/src/commands/compile.rs	Avoids calling create_dir_all with an empty parent path when emitting output files.
crates/swc_cli_impl/tests/issues.rs	Adds a regression test to ensure --out-file in the current directory succeeds.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[github-actions]

Binary Sizes

File	Size
swc.linux-x64-gnu.node	28M (29065032 bytes)

Commit: 2f6b10c

[codspeed-hq]

Merging this PR will not alter performance

✅ 219 untouched benchmarks

---

_{Comparing claude/issue-11717-20260320-0904 (b3c1f62) with main (33fe6f2)}