MacCVS

A modern, native CVS client for macOS, written in SwiftUI. A spiritual successor to the classic MacCVS / cvsgui — which was a PowerPC/Carbon app that has been unrunnable since macOS Catalina removed Carbon and 32-bit support. MacCVS is a fresh, universal (Apple Silicon + Intel), notarized app that drives your existing cvs command-line tool.

Why

CVS is old, but plenty of long-lived projects still live in it. The good graphical clients were left behind years ago:

• MacCVS (cvsgui) — Carbon/PowerPlant, dead since Catalina.
• gCVS — GTK2 + libglade, a multi-day dependency-porting project on modern macOS.
• TkRev/TkCVS — still works (Tcl/Tk), but not a native Cocoa app.

MacCVS is a small native app that wraps the cvs CLI you already have and gives it a fast, modern macOS front end.

Features

• Finder-style column browser for the directory hierarchy (real NSBrowser). The first column is a project switcher listing the CVS working copies you've opened; right-click to Forget one or reveal it in Finder.
• File list showing every file's CVS status and revision, with sortable Name / Status / Rev columns.
• Instant local change detection. A file's modified state is determined by comparing its modification time to the timestamp CVS recorded in CVS/Entries — exactly how cvs decides — with no network round-trip. An FSEvents watcher flips files to Modified the moment you save.
• Instant diffs. When a file changes, its base revision is fetched in the background and cached, so opening a diff is immediate (no waiting on the server).
• Native side-by-side diff window (see below): line- or word-level highlighting, a unified-view toggle, a draggable center divider, and multi-file diffs in one window. The window auto-sizes to fit the content.
• Core CVS operations: Update, Commit (with a per-file picker), Diff, Log, Add, Revert (update -C).
• History window: cvs log is parsed into a clean timeline of revisions (revision, author, date, ± line counts, message). A Show diffs toggle loads the visual diff each revision introduced, inline and on demand.
• View filters: hide dot-files and non-CVS files by default, toggle from the View menu (⌘⇧. and ⌘⇧U).
• Remembers your last project and directory across launches.
• Automatic updates: once a day MacCVS checks GitHub Releases; if a newer build exists it offers to update, then downloads it, verifies it is notarized, and relaunches into the new version. Also available on demand from the app menu (MacCVS ▸ Check for Updates…).

The diff viewer

The diff viewer is a standalone, resizable window. Its data model and side-by-side visual style are adapted from swifty-diff (MIT); MacCVS adds a cvs diff parser, a real window, a unified-view toggle, a draggable divider, and word-level (intra-line) highlighting.

• Side by side / Unified toggle.
• Line / Word toggle — Word highlights only the changed tokens within a line.
• Drag the center divider to rebalance the two panes; each pane scrolls its own long lines while vertical scrolling stays in sync.
• Select several modified files and Diff them all into one window.

Requirements

• macOS 14 (Sonoma) or later.
• Nothing else — MacCVS bundles its own cvs. You do not need to install CVS. A self-contained universal CVS 1.11.23 client ships inside the app (Contents/Resources/cvs, linking only the system libraries), and MacCVS always uses that one, never the system's cvs. See THIRD-PARTY.md and build-cvs.sh for how it's built.

Install

Download the latest notarized build from the Releases page, unzip, and drag MacCVS.app to your Applications folder.

Build from source

git clone https://github.com/johnbuckman/MacCVS.git
cd MacCVS
swift build -c release          # or: ./build.sh  (assembles a universal .app)

build.sh produces a universal (arm64 + x86_64) MacCVS.app. Notarized releases are produced with release.sh (Developer ID signing + notarytool).

Command line

MacCVS accepts a few command-line options, so it can be scripted or used as a graphical diff viewer by other programs. Invoke the executable inside the bundle (or open -a MacCVS --args …):

MacCVS=/Applications/MacCVS.app/Contents/MacOS/MacCVS

"$MacCVS" /path/to/workingcopy      # open a working copy
"$MacCVS" --open /path/to/workingcopy
"$MacCVS" --diff FILE...            # CVS diff (repo vs working) of one or more files
"$MacCVS" --diff lib/a.tcl lib/b.tcl lib/c.tcl   # several files, one window
"$MacCVS" --compare LEFT RIGHT      # visual diff between two arbitrary files
"$MacCVS" --help

--diff accepts any number of files and shows all of their CVS diffs together in one window. In --diff/--compare mode MacCVS shows only the diff window (no main window) and quits when it is closed — so another program can call it to display a diff, e.g. as a git difftool (which passes two files to compare):

git config --global difftool.maccvs.cmd \
  '/Applications/MacCVS.app/Contents/MacOS/MacCVS --compare "$LOCAL" "$REMOTE"'
git difftool -t maccvs

Architecture

MacCVS is a thin GUI over the cvs CLI — it never re-implements the CVS protocol.

• CVSService execs the bundled cvs directly via Process (no shell), and computes local modified-state from CVS/Entries timestamps.
• WorkingCopyStore is the app state (@MainActor ObservableObject): the file list, the FSEvents watcher, the base-revision prefetch cache, and all operations.
• DirectoryColumnBrowser wraps NSBrowser for the column view + project switcher.
• SwiftyDiff holds the diff model, the unified-diff parser, word-level diffing, and the SwiftUI diff window.

Credits & license

MacCVS is licensed under the GNU General Public License v3.0 (see LICENSE).

It bundles GNU CVS 1.11.23 (GPL-2-or-later) as a separate executable, and the diff viewer adapts the model and visual style of swifty-diff by Michael Neale (MIT). See THIRD-PARTY.md.