feat: option to prevent cross-filesystem traversal by KSXGitHub · Pull Request #363 · KSXGitHub/parallel-disk-usage

KSXGitHub · 2026-03-22T18:27:18Z

Closes #349.

This PR adds support for skipping directories on different filesystems, similar to the -x/--one-file-system flag found in tools like du. This allows users to analyze disk usage within a single filesystem without counting mounted directories.

https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Directories on different devices (mount points) were being traversed, leading to inaccurate usage reports and severe performance issues. Compare each entry's device ID against the root's device ID and treat cross-device directories as leaf nodes. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Instead of unconditionally skipping cross-device directories, make it opt-in via -x/--one-file-system (matching du convention). The default behavior now crosses device boundaries like du, dust, and dua. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

github-actions · 2026-03-22T18:34:22Z

Performance Regression Reports

commit: b00e32c

There are no regressions.

…tforms The `volume_serial_number()` API requires `windows_by_handle` which is an unstable library feature (rust-lang/rust#63010), so --one-file-system cannot be supported on Windows with stable Rust. Instead, return a RuntimeError::UnsupportedFeature(OneFileSystem) early and remove the Windows-specific device_id implementation. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Copilot

Pull request overview

Adds a --one-file-system / -x option to keep traversal within the root filesystem (similar to du -x), wiring the flag through the CLI/app layers into FsTreeBuilder, and updating generated help/docs and tests accordingly.

Changes:

Introduced filesystem device-id detection and used it in FsTreeBuilder to skip descending into directories on other filesystems when enabled.
Added --one-file-system / -x CLI flag and threaded it through App → Sub → FsTreeBuilder.
Updated tests and regenerated help/usage/completion exports to include the new option.

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
`src/fs_tree_builder.rs`	Adds `one_file_system` config and device-id checks during traversal.
`src/fs_tree_builder/device_id.rs`	New platform-gated device-id helper used by `FsTreeBuilder`.
`src/args.rs`	Adds `--one-file-system` / `-x` flag to CLI args (Unix-gated in help).
`src/app.rs`	Validates/threads the flag and rejects it on non-Unix builds.
`src/app/sub.rs`	Plumbs `one_file_system` into the `FsTreeBuilder` invocation.
`src/runtime_error.rs`	Adds `UnsupportedFeature::OneFileSystem` for non-Unix.
`tests/usual_cli.rs`	Updates FsTreeBuilder construction in CLI snapshot-style tests.
`tests/json.rs`	Updates FsTreeBuilder construction for JSON-related test.
`tests/cli_errors.rs`	Updates FsTreeBuilder construction for error-path tests.
`tests/_utils.rs`	Updates shared FsTreeBuilder helper construction used by tests.
`exports/short.help`	Regenerated short help including the new flag.
`exports/long.help`	Regenerated long help including the new flag.
`exports/completion.bash`	Regenerated bash completions including the new flag.
`exports/completion.zsh`	Regenerated zsh completions including the new flag.
`exports/completion.fish`	Regenerated fish completions including the new flag.
`exports/completion.ps1`	Regenerated PowerShell completions including the new flag.
`exports/completion.elv`	Regenerated Elvish completions including the new flag.
`USAGE.md`	Regenerated usage docs including the new flag.
`README.md`	Removes prior limitation statement about not differentiating filesystems.

src/args.rs

src/runtime_error.rs

src/fs_tree_builder.rs

src/fs_tree_builder/device_id.rs

USAGE.md

tests/_utils.rs

The `#[clap(long)]` attribute on `one_file_system` already generates `--one-file-system`, so `visible_alias = "one-file-system"` was a duplicate causing doubled anchors in USAGE.md and redundant entries in shell completions. Regenerate all exports. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Unit tests in device_id.rs verify that get_device_id returns equal IDs for the same filesystem and different IDs across filesystems (/ vs /proc). Integration tests in one_file_system.rs: - same_device_on_sample_workspace: one_file_system=true produces the same tree as false when all files are on one device - cross_device_excludes_mount: uses unshare --user --mount --map-root-user to create a tmpfs mount inside a user namespace (no root required) and verifies -x excludes entries on the mounted filesystem https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

The different_filesystem_returns_different_ids unit test uses /proc (Linux-only) and /dev (macOS devfs), so split into two functions gated with #[cfg(target_os = "linux")] and #[cfg(target_os = "macos")]. The cross_device_excludes_mount integration test uses unshare which is Linux-only, so gate it with #[cfg(target_os = "linux")]. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Copilot

Pull request overview

Copilot reviewed 20 out of 20 changed files in this pull request and generated 1 comment.

tests/one_file_system.rs

- Use `writeln!` to build the shell script instead of `format!` with inline braces, making the script construction clearer - Use `command_extra::CommandExtra` with `.with_args`/`.with_stdout`/ `.with_stderr` instead of bare `std::process` methods - Import `pretty_assertions::assert_eq` at module level https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

…tput Write each pdu invocation's output to a separate temp file, then emit them NUL-delimited with labels. Use find_section() to locate each section by label instead of splitting on '===' and indexing. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Replace the silent skip with a panic and actionable error message, matching the pattern from `fs_errors`. The test can be excluded via `RUSTFLAGS='--cfg pdu_test_skip_cross_device'`. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

The previous check only verified that `unshare --user --mount --map-root-user` succeeds, but not that tmpfs mounting is permitted inside the namespace. On systems where user namespaces work but unprivileged mounts are blocked, the test would fail instead of being caught by the probe. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

A bool discards the reason for failure. Return a Result with the stderr output from the probe command so the panic message includes actionable diagnostics (e.g. "unshare: unshare failed: Operation not permitted"). https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Replace the user-namespace-based (`unshare --user --mount`) cross-device test with a FUSE-based approach using `fuse2fs`. User namespaces are often disabled in CI containers, making the unshare test unreliable. The new test creates a small ext2 filesystem image, mounts it via `fuse2fs` (which only needs `/dev/fuse` and `fusermount`), and verifies that `pdu -x` correctly excludes entries on the mounted filesystem. Diagnostic messages clearly report which FUSE component is missing. The `--cfg pdu_test_skip_cross_device` skip flag is preserved. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Copilot

Pull request overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated 3 comments.

tests/one_file_system.rs

The `cross_device_excludes_mount` test requires `fuse2fs` (from e2fsprogs) and `fusermount3` (from fuse3) to mount an ext2 image via FUSE. Install these packages on Linux runners in both test.yaml and deploy.yaml so the test can run in CI without being skipped. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Copilot

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 2 comments.

src/args.rs

tests/one_file_system.rs

https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

src/device.rs

Align with the existing naming convention used by `Direction::from_top_down` and `BarAlignment::from_align_right`. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

Copilot

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated no new comments.

Copilot

Pull request overview

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

src/fs_tree_builder.rs

claude added 5 commits March 22, 2026 16:34

refactor(api): use pub(crate) visibility for device_id items

02edc48

https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

docs(readme): remove outdated mounted filesystems limitation

7b4889d

https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

chore(cli): regenerate completions, help text, and usage docs

e7df5d8

https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

claude and others added 2 commits March 22, 2026 18:39

docs(cli): hide -x on windows

3f7db4b

KSXGitHub requested a review from Copilot March 22, 2026 19:10

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claude added 3 commits March 22, 2026 19:30

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claude added 9 commits March 22, 2026 21:38

Merge origin/master into claude/fix-mounted-directories-pEvuV

1518b5e

chore(git): merge from master

b21eea3

chore(git): merge from master

2c0e4ba

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KSXGitHub requested a review from Copilot March 27, 2026 16:52

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chore(git): merge from master

876739a

https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

KSXGitHub force-pushed the claude/fix-mounted-directories-pEvuV branch from 054aa8f to 876739a Compare March 27, 2026 17:38

KSXGitHub and others added 3 commits March 28, 2026 00:50

feat(cli): set conflict

4744905

fix: completions

27c740c

test: set --min-ratio

077cbf0

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

KSXGitHub requested a review from Copilot March 27, 2026 17:58

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refactor(device): rename from_1fs to from_one_file_system

4e6f084

Align with the existing naming convention used by `Direction::from_top_down` and `BarAlignment::from_align_right`. https://claude.ai/code/session_01LfpnUZrgq93MVZgA3KVqE6

KSXGitHub requested a review from Copilot March 27, 2026 18:07

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KSXGitHub added 4 commits March 28, 2026 01:23

refactor: reduce verbosity

8b06f9e

refactor: use pipe

88c7d8d

refactor: rename some variables

30f37bc

docs: remove the obvious error message

52d95d7

KSXGitHub requested a review from Copilot March 27, 2026 18:36

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KSXGitHub requested review from Copilot and removed request for Copilot March 27, 2026 18:41

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style: add an empty line

cfddd52

KSXGitHub force-pushed the claude/fix-mounted-directories-pEvuV branch from 3fab8d3 to cfddd52 Compare March 27, 2026 18:43

KSXGitHub marked this pull request as ready for review March 27, 2026 18:53

KSXGitHub merged commit 5a88f61 into master Mar 27, 2026
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KSXGitHub deleted the claude/fix-mounted-directories-pEvuV branch March 27, 2026 18:57

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