jjk leaves orphaned jj-diff-XXXXXX directories in the OS temp dir. They accumulate indefinitely and each contains a full materialized checkout of the repo, so on large repos they consume enormous space. On my machine they grew to 4,101 directories totaling ~440 GB, filling my disk to 100%.
Environment
- jjk: v0.11.0
- jj: 0.42.0
- OS: macOS (Apple Silicon)
- No external
ui.diff.tool / ui.diff-editor configured by me; jjk is the only thing invoking jj's external-tool diff path.
What I observed
$TMPDIR contained thousands of jj-diff-* dirs, created in bursts of 100–200+ per minute during active editing sessions.- Each dir contains jj's materialized trees:
left, left_state, and sometimes right, right_state.
- The majority have only
left/left_state (no right); i.e. the jj process was terminated early, after the left tree was checked out but before the right.
- A leftover
jjk-signal-* dir was also present.
Likely mechanism
jjk drives jj's interactive diff machinery with the bundled fakeeditor, e.g.:
jj squash --from … --into … --interactive --tool <fakeeditor> --use-destination-message …
jj materializes the trees into a jj-diff-* temp dir (cleaned up by Rust's tempfile::TempDir only on graceful process exit) and runs the tool. jjk's bundle calls .kill() / process.kill(pid, "SIGTERM") on the jj/fakeeditor child processes when an operation is cancelled or superseded (the SCM/graph view refreshes on every file change, so in-flight operations are killed frequently).
A jj process killed by SIGTERM never runs the TempDir destructor, so the jj-diff-* dir is orphaned. The prevalence of left-only dirs is consistent with the kill arriving mid-checkout. This isn't really a jj bug, a signal-killed process can't clean its own temp dir, but jjk triggers these checkouts and kills the process without cleaning up after itself.
jjk leaves orphaned
jj-diff-XXXXXXdirectories in the OS temp dir. They accumulate indefinitely and each contains a full materialized checkout of the repo, so on large repos they consume enormous space. On my machine they grew to 4,101 directories totaling ~440 GB, filling my disk to 100%.Environment
ui.diff.tool/ui.diff-editorconfigured by me; jjk is the only thing invoking jj's external-tool diff path.What I observed
$TMPDIRcontained thousands ofjj-diff-*dirs, created in bursts of 100–200+ per minute during active editing sessions.left,left_state, and sometimesright,right_state.left/left_state(noright); i.e. the jj process was terminated early, after the left tree was checked out but before the right.jjk-signal-*dir was also present.Likely mechanism
jjk drives jj's interactive diff machinery with the bundled fakeeditor, e.g.:
jj materializes the trees into a
jj-diff-*temp dir (cleaned up by Rust'stempfile::TempDironly on graceful process exit) and runs the tool. jjk's bundle calls.kill()/process.kill(pid, "SIGTERM")on the jj/fakeeditor child processes when an operation is cancelled or superseded (the SCM/graph view refreshes on every file change, so in-flight operations are killed frequently).A jj process killed by SIGTERM never runs the
TempDirdestructor, so thejj-diff-*dir is orphaned. The prevalence ofleft-only dirs is consistent with the kill arriving mid-checkout. This isn't really a jj bug, a signal-killed process can't clean its own temp dir, but jjk triggers these checkouts and kills the process without cleaning up after itself.