Use TurtleGitMerge with Git

TurtleGitMerge can open native two-file comparison, three-file merge, and patch review directly from a terminal. The waiting wrapper is scripts/turtlegit-merge. By default it uses /Applications/TurtleGit for Mac.app; set TURTLEGIT_APP to another app bundle, or TURTLEGIT_MERGE_EXECUTABLE to a development executable.

Choose a comparison interface

The Interface selector in text comparison and conflict windows offers Classic (the default) or P4Merge-style. The choice is shared and saved for later diff/merge windows. Both interfaces use the same comparison, editing, Undo/Redo, source-choice and save operations.

The alternative two-file view connects changed blocks with curved colored bands. Three-way merge follows the four-pane P4Merge arrangement: Theirs / Base / Yours above an editable Merge result. Purple identifies Theirs, yellow the common Base, and green Yours. The source panes show their original lines, so insertions and deletions have different heights joined by curved ribbons.

The compact toolbar and flat file headers leave more room for text. Unresolved regions show the source candidates in yellow, purple and green, joined to the result by a colored flow gutter. This is a display projection: Git conflict markers remain in the underlying result, and Save still warns about unresolved conflicts. Typing within a candidate region resolves that region to its visible contents plus your edit; Undo restores its conflict state.

The compact colored source buttons beside each result chunk are toggles. Select a source to include it; select it again to remove it. You can combine sources in click order. Identical text is included once. The three Use whole file controls replace the result with that complete source. All choices and manual result edits support Undo/Redo. A gray result band identifies manually edited text. Save uses the same output target, encoding checks and conflict-resolution safeguards as Classic. The source/result divider position is saved independently of the classic layout.

Changing the interface preserves the current result. If an edit crosses several engine regions and destroys their exact result mapping, that region's source buttons are disabled; Undo or reload restores the mapping. P4Merge-style is a TurtleGit presentation inspired by Perforce's tool, not the Perforce application.

Use the wrapper's absolute path in your Git configuration. For example, after placing it at ~/bin/turtlegit-merge:

git config --global diff.tool turtlegit
git config --global difftool.turtlegit.cmd '"$HOME/bin/turtlegit-merge" --base "$LOCAL" --mine "$REMOTE" --readonly'
git config --global merge.tool turtlegit
git config --global mergetool.turtlegit.cmd '"$HOME/bin/turtlegit-merge" --base "$BASE" --theirs "$REMOTE" --mine "$LOCAL" --merged "$MERGED" --saverequired'
git config --global mergetool.turtlegit.trustExitCode true

Then use git difftool or git mergetool. Each command starts its own tool process, waits for the editor to close and returns its result to Git. A three-file merge reports success only after the result was saved, has no remaining conflict markers and has no newer unsaved edits. Discarding a requested merge result does not mark the Git merge successful. Saving a separate merged output preserves the Base/Theirs/Mine inputs. No automatic staging occurs in this standalone editor.

Direct examples:

~/bin/turtlegit-merge --base old.txt --mine new.txt --readonly
~/bin/turtlegit-merge --base base.txt --theirs remote.txt --mine local.txt --merged result.txt --saverequired
~/bin/turtlegit-merge --diff change.patch --patchpath ./target
~/bin/turtlegit-merge --diff change.patch --patchpath ./target --reversedpatch
~/bin/turtlegit-merge --createunifieddiff --origfile old.txt --modifiedfile new.txt --outfile change.patch

Standalone requests open only the requested Merge editor or chooser, with its File, Edit, Navigate, View and Help commands. They do not open a repository workspace or start Finder monitoring. A Finder action or patch-file open received while this tool process is running is handed to a new workspace process. It does not replace the Git editor or alter the Git result. Tool exit waits for an accepted workspace launch and any owned launch-error acknowledgment. The new workspace still performs its normal repository/file authorization. With no file arguments the tool opens its native Open dialog. A patch without a target asks for the target directory; a target without a patch asks for the patch. --wc uses a supplied patch's containing folder as its default target. Read-only and Blame requests retain navigation while refusing file mutations. --line is one-based. Descriptive names such as --basename and --mergedname affect captions. Reflected names remain display metadata, never input/output paths or access grants. The editor's Create unified diff file command uses Git-relative reflected header names when both names belong to the same working tree; the separate --createunifieddiff command retains its ordinary generated headers. File/Open resets descriptive labels and the merged-output target while preserving read-only/Blame policy and reflected names for the replacement document.

--blame compares the fixed-width metadata-prefixed text format used by the source tool. Where source encoding, line endings or comparison options require conversion, matching omits the first 66 UTF-16 code units of lines longer than 66 units. The displayed source text and line numbers remain intact. Plain UTF-8 or ASCII inputs may bypass that source conversion path. This option does not request Git history or add Blame columns. Missing merge inputs are shown as empty panes. A file appearing or changing while an edit is open requires Reload before it can be accepted as the new baseline.

A sandboxed App Store build requires file/folder authorization for command-line paths, including a missing output's parent directory. A terminal path is not a security-scoped grant. Canceling an authorization chooser ends the waiting command unsuccessfully without a permission-renewal error. A wrong selection can be corrected in the chooser. Interactive Open authorizes typed role paths before checking their existence; it still rejects missing inputs after authorization. The tool retains its input/output grants until the command and owned panels finish. See authorization behavior for the connected workflow and verification scope. Store distribution and physical signed acceptance remain separate release checks.

--deletebasetheirsmineonclose is intended for disposable tool inputs. It removes only explicitly supplied input objects whose identity and contents still match the captured input, after owned editor work drains; it preserves changed inputs and the merged output. It never removes a symlink target. This is a deliberate macOS ownership adaptation to the source cleanup flag.

In a three-file merge, View → Line diff bar can display a compact Theirs/Mine comparison below the panes. It follows the inspected line and always shows whitespace and inline differences, even when those markers are hidden in the editors. The strip preserves your selection and keyboard focus. Three-file loads initially hide it; changing Locator visibility restores its saved choice. View → Line numbers changes the current window's numbering without changing the Merge Editor Settings default.

See the source entry review and two-file behavior review for remaining states and platform differences. This does not certify complete TortoiseMerge parity.

The P4Merge-style toolbar has separate previous/next controls for all differences and unresolved conflicts (red arrows). Resolved chunks are skipped by conflict navigation. It also offers Find, Go to Line, line numbers, whitespace and word wrap. Included source symbols use their source color; excluded symbols are filled gray. Identical alternatives sit together with an = between them and toggle the shared text once. A + or − badge indicates an insertion or deletion relative to Base, independently of selection. Hovering shows the source, identical peers and a hand cursor. Each chunk has one aligned row on a neutral gutter. Highlight bands continue through the line-number margin, with overlay scrollbars keeping the connector edges clear.