MacDirStat v1.3.0

A performance-focused release: the scanner, the in-memory tree, and live
refresh were all rebuilt for speed on very large volumes, plus new ways to
save, reopen, and compare scans.

Added

• Auto-summarization of dependency and cache folders: directories like
  node_modules (and anything else that looks like thousands of tiny
  files, by heuristic) collapse into a single summary row carrying the
  total size and file count, instead of building a chart node for every
  file inside. On a real Projects folder this cut a scan from 16.0s /
  910,550 nodes to 8.6s / 104,551 nodes, with byte-identical totals.
• Save and reopen scans: File > Save Scan... writes the current scan to
  an .mdscan file; File > Open Scan... reopens it later as a read-only
  snapshot (no delete actions, no live watching), with a banner showing
  when it was captured. Opening a corrupted or tampered file surfaces an
  error instead of crashing.
• Compare two scans: File > Compare With Saved Scan shows what changed
  between now and a saved snapshot: added, removed, grown, shrunk, and
  files that were replaced by a folder (or vice versa) at the same path. A
  whole added or removed directory collapses into a single row instead of
  listing every file inside it.
• Drag-to-grant Full Disk Access: the guided permission sheet now shows
  the running app's own icon as a draggable tile, so granting access can't
  accidentally target the wrong build sitting in a file picker (macOS ties
  the grant to one exact copy). A "Show this app in Finder" fallback covers
  drag-and-drop from a Finder window instead.
• Permissions section in Settings: check and fix Full Disk Access
  directly from Settings, with a live coloured-dot status, the same
  drag-to-grant tile, and a direct link to the right System Settings pane.

Changed

• The scanner now enumerates directories with getattrlistbulk(2),
  reading names and metadata in one batched syscall per directory instead
  of one readdir plus one fstatat per entry, with a readdir fallback
  for filesystems that don't support it. Traversal itself moved from
  unbounded recursive fan-out to a bounded worker pool, so a scan no longer
  spawns more concurrent work than the machine can use.
• The in-memory scan result is now a flat, contiguous store instead of a
  tree of individual objects per file and folder, which noticeably lowers
  memory use and speeds up sorting and layout on very large scans.
• Live refresh (the automatic re-scan while a folder is open and being
  watched) now patches only the part of the tree that actually changed
  instead of rescanning the whole root, so background file activity no
  longer causes a visible full reload.
• Move to Trash now removes the deleted item from the current scan
  directly instead of triggering a full rescan, so deleting from the
  Duplicates view no longer bounces you back to the Treemap tab. Fixes
  #5.

Fixed

• Scanning / (or any volume root) could dramatically under-report disk
  usage, in one case showing 11.8 GB instead of the real 479.3 GB, because
  /Users, /Applications, /Library, /opt, /private, /Volumes and
  /cores are macOS firmlinks and were being silently dropped as 0 bytes.
  Directory identity, mount-boundary checks, and alias de-duplication are
  now all decided from the opened directory instead of from what the
  parent folder's listing claimed, which is the only place a firmlink
  resolves correctly.
• A background summarization pass (used for node_modules-style folders)
  could, under load, block every available concurrency thread at once and
  wedge a scan so it never finished and could not be stopped. It is now
  fully asynchronous end to end.
• Scanning a volume root and then letting a live file change happen could
  crash the app outright ("Index out of range") because of a bookkeeping
  gap in the synthetic "Hidden & Unreadable Space" entry.
• A live filesystem change that couldn't be folded into the current scan
  incrementally could escalate into a full rescan that cleared the
  Treemap mid-render and then repeated forever. Such changes are now
  skipped with a "Rescan" button offered instead, rather than looping.
• Comparing two scans now reports a file replaced by a folder (or a folder
  replaced by a file) at the same path as a change, instead of dropping it
  from the results entirely.
• Fixed several cases where disk usage from hardlinked files could be
  under- or double-counted after trashing a file, after a live refresh, or
  after an external process (Finder, rm, a build tool) deleted the copy
  that was carrying the reported size, including ordering glitches in
  ancestor folders left over from the fix.
• The Full Disk Access sheet no longer claims "Access granted!" when the
  most recent scan still hit denied folders; it only shows success for a
  grant it actually watched happen while it was open.
• GitHub Releases now include a proper .dmg installer image alongside
  the signed zip, instead of shipping only a bare executable archive.
  Fixes #22.

Test suite grew from 50 to 142 tests across this cycle, all passing.

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Install

Open the DMG and drag DirStat to Applications. The disk image is Developer ID signed and notarized by Apple, so it opens without a security warning.

For a complete scan of your whole disk, grant Full Disk Access: Settings (gear icon) > Permissions, then drag the app tile into the list. macOS ties the grant to one exact copy of an app, which is why dragging the running app is more reliable than adding it with the "+" button.

Packaged as a DMG rather than a zip: the app embeds Sparkle for auto-updates, and Sparkle's framework contains symlinks that messaging apps and third-party unarchivers routinely flatten out of a zip, which breaks the signature and makes macOS report the app as damaged. Fixes #22.