Fallback created for git commands not standard handled by this module

README.md

@@ -23,7 +23,23 @@ procedure and through direct procedures.
 ```
 
 `git` is an ordinary procedure. The first argument is the Git command symbol
-and the remaining arguments are passed to that command.
+and the remaining arguments are passed to that command. Registered commands use
+their git-cli wrapper and can provide structured Racket results or additional
+behavior. Any other command is passed directly to the installed Git executable
+and handled with git-cli's standard command result processing.
+
+For example, commands that do not have a dedicated wrapper can still be used:
+
+```racket
+(git 'blame "main.rkt")
+(git* clean -n)
+(git* worktree list)
+(git* archive --format=zip HEAD)
+```
+
+A successful fallback command returns `#t` after displaying normal Git output.
+A failing fallback command raises the same standard git-cli error as an ordinary
+pass-through wrapper.
 
 `git*` is the compact command-style syntax. Bare arguments are converted to
 strings, so `(git* remote get-url origin)` is equivalent to
@@ -69,12 +85,16 @@ credentials, SSH keys, pull strategy, and other repository configuration.
 
 ## Commands
 
-The package currently registers commands including `init`, `status`, `add`, `commit`,
+The package registers wrappers for commands where git-cli adds useful behavior,
-`push`, `pull`, `fetch`, `config`, `branch`, `remote`, `stash`, `restore`, `reset`, `revert`, `rebase`, `merge`, `cherry-pick`, `mergetool`, `switch`, `clone`, `tag`, `log`,
+including `init`, `status`, `add`, `commit`, `push`, `pull`, `fetch`, `config`,
-`rev-list`, `diff`, `show`, `grep`, `help`, `version`, and `new-version`.
+`branch`, `remote`, `stash`, `restore`, `reset`, `revert`, `rebase`, `merge`,
+`cherry-pick`, `mergetool`, `switch`, `clone`, `tag`, `log`, `rev-list`, `diff`,
+`show`, `grep`, `help`, `version`, and `new-version`. Other Git commands do not
+need a wrapper and are passed directly to Git.
 
-Most are also exported as direct procedures such as `git-init`, `git-status`, `git-add`,
+Most registered commands are also exported as direct procedures such as
-`git-fetch`, `git-config`, `git-switch`, `git-tag`, `git-log`, `git-diff`, and `git-show`.
+`git-init`, `git-status`, `git-add`, `git-fetch`, `git-config`, `git-switch`,
+`git-tag`, `git-log`, `git-diff`, and `git-show`.
 
 See the Scribble documentation for command-specific behavior and return values.
 
@@ -111,17 +131,41 @@ The non-interactive forms are:
 
 ```racket
 (git* config editor --list)
+(git* config editor --downloads)
 (git* config editor vscode)
+(git* config editor notepad++)
 (git* config editor auto)
 
 (git 'config 'editor "C:\\Program Files\\MyEditor\\editor.exe --wait")
 ```
 
-`--list` returns `(name description command current?)` items. A known editor
+`--list` returns `(name description command current?)` items and `--downloads`
-name selects the matching detected editor. `auto` clears the explicit git-cli
+returns official download pointers for optional editors. A known editor name
-editor choice and returns to automatic detection. Any other single value is
+selects the matching detected editor. `auto` clears the explicit git-cli editor
-stored as the editor command. Changing the editor immediately updates
+choice and returns to automatic detection. Any other single value is stored as
-`GIT_EDITOR` and `GIT_SEQUENCE_EDITOR` for subsequent Git commands.
+the editor command. Changing the editor immediately updates `GIT_EDITOR` and
+`GIT_SEQUENCE_EDITOR` for subsequent Git commands.
+
+On Windows, Notepad++ is detected both on `PATH` and in the normal Program Files
+locations. It is started with `-multiInst -nosession`, so Git waits for the
+separate editor instance to close.
+
+
+`config mergetool` uses the same git-cli configuration pattern:
+
+```racket
+(git* config mergetool)
+(git* config mergetool --list)
+(git* config mergetool --downloads)
+(git* config mergetool winmerge)
+(git* config mergetool auto)
+```
+
+`--list` returns `(name description path current?)` items. A known tool name
+selects the detected tool, while another single value is stored as the Git
+mergetool name. `auto` clears the explicit git-cli choice and returns to
+automatic detection. The interactive form also offers download/install
+suggestions.
 
 ## Low-level Git execution
 
@@ -180,7 +224,7 @@ The editor can be inspected or configured explicitly:
 
 The editor search first checks `PATH` and then well-known platform locations.
 On Windows this includes the normal per-user and Program Files locations for
-VS Code, with Notepad as fallback. On macOS the standard Visual Studio Code
+VS Code and Notepad++, with Notepad as fallback. On macOS the standard Visual Studio Code
 application bundle and TextEdit are recognized. On Linux common `/usr`,
 `/usr/local`, and Snap locations are checked for VS Code, Kate, Gedit, and Xed.
 
@@ -193,8 +237,11 @@ If no tool is found, Git is left to select its own default.
 
 ```racket
 (find-mergetool)
+(find-mergetools)
 (find-mergetool-path)
+(mergetool-downloads)
 (set-mergetool! "winmerge")
+(set-mergetool-auto!)
 (git* mergetool)
 (git* mergetool --tool=meld)
 ```

info.rkt

@@ -2,7 +2,7 @@
 
 (define collection "git-cli")
 (define pkg-desc "Command-line-like Git operations for Racket, interface to the git cli command")
-(define version "0.3.40")
+(define version "0.4.0")
 (define pkg-authors '("Hans Dijkema"))
 (define license 'MIT)
 

main.rkt

@@ -10,6 +10,7 @@
          "private/find-mergetool.rkt"
          simple-log
          racket/string
+         racket/list
          net/sendurl
          )
 
@@ -48,11 +49,15 @@
          git-next-version
          find-editor
          find-editors
+         editor-downloads
          set-editor!
          set-editor-auto!
          find-mergetool
+         find-mergetools
          find-mergetool-path
+         mergetool-downloads
          set-mergetool!
+         set-mergetool-auto!
          default-git-authentication-handler
          current-git-authentication-handler
          exn:fail:git-auth?
@@ -91,17 +96,26 @@
      (git* cmd arg ...))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; goal   : Invoke a supported Git command through the command table.
+; goal   : Invoke a Git command through a registered wrapper or direct fallback.
-; pre    : command is a registered Git command symbol.
+; pre    : command identifies a Git command and args contains its arguments.
-; post   : The selected command has processed all supplied arguments.
+; post   : Registered commands use their wrapper; other commands are passed to Git.
-; result : The command-specific result.
+; result : The command-specific result or the standard Git command result.
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (define (git command . args)
-  ((hash-ref git-commands command
+  (let ((cmd (hash-ref git-commands command #f)))
-             (λ ()
+    (if cmd
-               (error "Not a supported or recognized git command: " command)))
+        (cmd args)
-   args))
+        (let-values (((exit-code output)
+                      (run-git (cons command (flatten args)))))
+          (let-values (((result out) (git-out command output)))
+            (std-process-git-result
+             command
+             exit-code
+             result
+             output
+             out
+             (make-hash)))))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Supporting functions
@@ -261,6 +275,8 @@
                      (+ (length editors) 1)))
   (displayln (format "  ~a. Automatic detection"
                      (+ (length editors) 2)))
+  (displayln (format "  ~a. Download/install suggestions"
+                     (+ (length editors) 3)))
   (displayln "  0. Cancel")
   (newline))
 
@@ -275,6 +291,7 @@
     (display-editor-selection editors)
     (let* ((custom-index (+ (length editors) 1))
            (auto-index (+ (length editors) 2))
+           (downloads-index (+ (length editors) 3))
            (choice
             (input-prompt
              "Editor: "
@@ -286,7 +303,7 @@
                   (let ((n (string->number value)))
                     (if (and n
                              (integer? n)
-                             (<= 0 n auto-index))
+                             (<= 0 n downloads-index))
                         n
                         #f))))))))
       (cond
@@ -309,6 +326,10 @@
                (set-editor! command))))
         ((= choice auto-index)
          (set-editor-auto!))
+        ((= choice downloads-index)
+         (display-download-pointers
+          "Suggested editors:"
+          (editor-downloads)))
         (else #f)))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -326,6 +347,10 @@
           (git-argument=? (car args) '--list))
      (available-editors))
 
+    ((and (= (length args) 1)
+          (git-argument=? (car args) '--downloads))
+     (editor-downloads))
+
     ((and (= (length args) 1)
           (git-argument=? (car args) 'auto))
      (set-editor-auto!))
@@ -337,7 +362,177 @@
            (set-editor! (format "~a" (car args))))))
 
     (else
-     (error 'git-config "Expected config editor [--list|auto|editor-name|editor-command]"))))
+     (error 'git-config "Expected config editor [--list|--downloads|auto|editor-name|editor-command]"))))
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Display official download pointers.
+; pre    : items contains (name description url) items.
+; post   : The pointers have been displayed.
+; result : void.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (display-download-pointers title items)
+  (displayln title)
+  (newline)
+  (for-each
+   (λ (item)
+     (displayln (format "  ~a" (cadr item)))
+     (displayln (format "  ~a" (caddr item)))
+     (newline))
+   items)
+  (void))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return the merge tool description matching a configured tool name.
+; pre    : name can be formatted as a merge tool name.
+; post   : The merge tool list has only been inspected.
+; result : A (name description path) item, or #f.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (find-mergetool-by-name name)
+  (let ((name* (string-downcase (format "~a" name))))
+    (let loop ((tools (find-mergetools)))
+      (cond
+        ((null? tools) #f)
+        ((string=? (string-downcase (car (car tools))) name*)
+         (car tools))
+        (else
+         (loop (cdr tools)))))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return a Racket-oriented list of available merge tools.
+; pre    : The platform merge tool finder is available.
+; post   : No merge tool has been started.
+; result : (name description path current?) items.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (available-mergetools)
+  (let ((current (find-mergetool)))
+    (map
+     (λ (tool)
+       (list (car tool)
+             (cadr tool)
+             (caddr tool)
+             (and current
+                  (string=? current (car tool)))))
+     (find-mergetools))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Display the interactive git-cli merge tool selection.
+; pre    : tools contains the discovered merge tool descriptions.
+; post   : The choices have been displayed.
+; result : void.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (display-mergetool-selection tools)
+  (displayln "Available merge tools:")
+  (newline)
+  (let loop ((items tools)
+             (index 1))
+    (unless (null? items)
+      (let* ((tool (car items))
+             (current (find-mergetool))
+             (current? (and current
+                            (string=? current (car tool)))))
+        (displayln
+         (format "  ~a. ~a~a"
+                 index
+                 (cadr tool)
+                 (if current? "  [current]" "")))
+        (displayln (format "     ~a" (caddr tool)))
+        (newline)
+        (loop (cdr items) (+ index 1)))))
+  (displayln (format "  ~a. Specify another merge tool name"
+                     (+ (length tools) 1)))
+  (displayln (format "  ~a. Automatic detection"
+                     (+ (length tools) 2)))
+  (displayln (format "  ~a. Download/install suggestions"
+                     (+ (length tools) 3)))
+  (displayln "  0. Cancel")
+  (newline))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Ask the user to choose or enter the merge tool used by git-cli.
+; pre    : Standard input and output are available.
+; post   : A selected merge tool has been stored, automatic detection was restored,
+;          download pointers were shown, or the operation was cancelled.
+; result : The selected merge tool name, #f after cancellation, or void after pointers.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (configure-mergetool-interactively)
+  (let ((tools (find-mergetools)))
+    (display-mergetool-selection tools)
+    (let* ((custom-index (+ (length tools) 1))
+           (auto-index (+ (length tools) 2))
+           (downloads-index (+ (length tools) 3))
+           (choice
+            (input-prompt
+             "Merge tool: "
+             #:loop-until
+             (λ (value)
+               (cond
+                 ((eof-object? value) 'cancel)
+                 (else
+                  (let ((n (string->number value)))
+                    (if (and n
+                             (integer? n)
+                             (<= 0 n downloads-index))
+                        n
+                        #f))))))))
+      (cond
+        ((eq? choice 'cancel) #f)
+        ((= choice 0) #f)
+        ((<= choice (length tools))
+         (set-mergetool! (car (list-ref tools (- choice 1)))))
+        ((= choice custom-index)
+         (let ((tool
+                (input-prompt
+                 "Merge tool name: "
+                 #:loop-until
+                 (λ (value)
+                   (cond
+                     ((eof-object? value) 'cancel)
+                     ((string=? (string-trim value) "") #f)
+                     (else value))))))
+           (if (eq? tool 'cancel)
+               #f
+               (set-mergetool! tool))))
+        ((= choice auto-index)
+         (set-mergetool-auto!))
+        ((= choice downloads-index)
+         (display-download-pointers
+          "Suggested merge tools:"
+          (mergetool-downloads)))
+        (else #f)))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Process the git-cli-specific `config mergetool` command.
+; pre    : args contains the arguments following `mergetool`.
+; post   : The requested merge tool configuration action has been performed.
+; result : Merge tool data, the selected tool name, download pointers, or #f.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (git-config-mergetool args)
+  (cond
+    ((null? args)
+     (configure-mergetool-interactively))
+
+    ((and (= (length args) 1)
+          (git-argument=? (car args) '--list))
+     (available-mergetools))
+
+    ((and (= (length args) 1)
+          (git-argument=? (car args) '--downloads))
+     (mergetool-downloads))
+
+    ((and (= (length args) 1)
+          (git-argument=? (car args) 'auto))
+     (set-mergetool-auto!))
+
+    ((= (length args) 1)
+     (let ((tool (find-mergetool-by-name (car args))))
+       (if tool
+           (set-mergetool! (car tool))
+           (set-mergetool! (format "~a" (car args))))))
+
+    (else
+     (error 'git-config
+            "Expected config mergetool [--list|--downloads|auto|tool-name]"))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (git-config-args args info)
@@ -579,10 +774,15 @@
   process-git-config-result)
 
 (define (cmd-git-config args)
-  (if (and (pair? args)
+  (cond
-           (git-argument=? (car args) 'editor))
+    ((and (pair? args)
-      (git-config-editor (cdr args))
+          (git-argument=? (car args) 'editor))
-      (cmd-git-config-git args)))
+     (git-config-editor (cdr args)))
+    ((and (pair? args)
+          (git-argument=? (car args) 'mergetool))
+     (git-config-mergetool (cdr args)))
+    (else
+     (cmd-git-config-git args))))
 
 (define (git-config . args)
   (cmd-git-config args))

private/find-editor.rkt

@@ -6,6 +6,7 @@
 
 (provide find-editor
          find-editors
+         editor-downloads
          configured-editor
          set-editor!
          set-editor-auto!)
@@ -108,6 +109,20 @@
      "Visual Studio Code"
      (environment-path "ProgramFiles(x86)" "Microsoft VS Code" "bin" "code.cmd")
      " --wait")
+    (editor-on-path "notepad++"
+                    "Notepad++"
+                    "notepad++.exe"
+                    " -multiInst -nosession")
+    (editor-at
+     "notepad++"
+     "Notepad++"
+     (environment-path "ProgramFiles" "Notepad++" "notepad++.exe")
+     " -multiInst -nosession")
+    (editor-at
+     "notepad++"
+     "Notepad++"
+     (environment-path "ProgramFiles(x86)" "Notepad++" "notepad++.exe")
+     " -multiInst -nosession")
     (editor-on-path "notepad" "Notepad" "notepad.exe" "")
     (editor-at
      "notepad"
@@ -190,6 +205,23 @@
     ((unix) (find-unix-editors))
     (else '())))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return official download pointers for optional GUI editors.
+; pre    : The current platform is known.
+; post   : No network request has been made.
+; result : A list of (name description url) items.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (editor-downloads)
+  (case (system-type 'os)
+    ((windows)
+     '(("vscode" "Visual Studio Code" "https://code.visualstudio.com/download")
+       ("notepad++" "Notepad++" "https://notepad-plus-plus.org/downloads/")))
+    ((macosx)
+     '(("vscode" "Visual Studio Code" "https://code.visualstudio.com/download")))
+    ((unix)
+     '(("vscode" "Visual Studio Code" "https://code.visualstudio.com/download")))
+    (else '())))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; goal   : Read the editor explicitly configured for git-cli.
 ; pre    : The git-cli configuration is readable.

private/find-mergetool.rkt

@@ -4,9 +4,12 @@
          "config.rkt")
 
 (provide find-mergetool
+         find-mergetools
          find-mergetool-path
+         mergetool-downloads
          configured-mergetool
-         set-mergetool!)
+         set-mergetool!
+         set-mergetool-auto!)
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Supporting functions
@@ -62,6 +65,56 @@
            candidate
            (find-candidates (cdr candidates)))))))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return every usable merge tool candidate without duplicate tool names.
+; pre    : candidates contains merge tool candidate descriptions.
+; post   : PATH and the filesystem have only been inspected.
+; result : A list of (tool description path) items.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (find-all-candidates candidates)
+  (let loop ((remaining candidates)
+             (names '())
+             (result '()))
+    (cond
+      ((null? remaining)
+       (reverse result))
+      (else
+       (let ((candidate (find-candidate (car remaining))))
+         (cond
+           ((not candidate)
+            (loop (cdr remaining) names result))
+           ((member (car candidate) names)
+            (loop (cdr remaining) names result))
+           (else
+            (loop (cdr remaining)
+                  (cons (car candidate) names)
+                  (cons
+                   (list (car candidate)
+                         (mergetool-description (car candidate))
+                         (cadr candidate))
+                   result)))))))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return well-known graphical merge tool candidates for Windows.
+; pre    : Windows environment variables may or may not be defined.
+; post   : The environment has only been inspected.
+; result : Merge tool candidate descriptions in preference order.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return a display description for a known Git merge tool.
+; pre    : tool is a Git merge tool name.
+; post   : tool has only been inspected.
+; result : A human-readable description.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (mergetool-description tool)
+  (cond
+    ((string=? tool "winmerge") "WinMerge")
+    ((string=? tool "vscode") "Visual Studio Code")
+    ((string=? tool "kdiff3") "KDiff3")
+    ((string=? tool "meld") "Meld")
+    ((string=? tool "tortoisemerge") "TortoiseMerge")
+    ((string=? tool "opendiff") "FileMerge / opendiff")
+    (else tool)))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; goal   : Return well-known graphical merge tool candidates for Windows.
 ; pre    : Windows environment variables may or may not be defined.
@@ -159,9 +212,44 @@
 ; pre    : The git-cli configuration is readable.
 ; post   : The configuration has not been changed.
 ; result : The configured Git merge tool name, or #f.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return all well-known merge tools found on the current platform.
+; pre    : The platform and filesystem are available.
+; post   : No merge tool has been started.
+; result : A list of (name description path) items.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (find-mergetools)
+  (find-all-candidates (mergetool-candidates)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return official download pointers for optional merge tools.
+; pre    : The current platform is known.
+; post   : No network request has been made.
+; result : A list of (name description url) items.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (mergetool-downloads)
+  (case (system-type 'os)
+    ((windows)
+     '(("winmerge" "WinMerge" "https://winmerge.org/downloads/")
+       ("kdiff3" "KDiff3" "https://apps.kde.org/kdiff3/")
+       ("meld" "Meld" "https://meldmerge.org/")
+       ("vscode" "Visual Studio Code" "https://code.visualstudio.com/download")))
+    ((macosx)
+     '(("kdiff3" "KDiff3" "https://apps.kde.org/kdiff3/")
+       ("vscode" "Visual Studio Code" "https://code.visualstudio.com/download")))
+    ((unix)
+     '(("meld" "Meld" "https://meldmerge.org/")
+       ("kdiff3" "KDiff3" "https://apps.kde.org/kdiff3/")
+       ("vscode" "Visual Studio Code" "https://code.visualstudio.com/download")))
+    (else '())))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (configured-mergetool)
-  (cfg-get 'git 'mergetool #f))
+  (let ((tool (cfg-get 'git 'mergetool #f)))
+    (if (and (string? tool)
+             (not (string=? tool "")))
+        tool
+        #f)))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; goal   : Store the Git merge tool name used by git-cli.
@@ -172,6 +260,20 @@
 (define (set-mergetool! tool)
   (cfg-set! 'git 'mergetool tool))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return git-cli to automatic merge tool detection.
+; pre    : A well-known merge tool can be found on the current platform.
+; post   : The explicit merge tool setting is cleared.
+; result : The automatically detected Git merge tool name.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (set-mergetool-auto!)
+  (let ((detected (detected-mergetool)))
+    (if detected
+        (begin
+          (cfg-set! 'git 'mergetool "")
+          (car detected))
+        (error 'git-config "No well-known merge tool found"))))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; goal   : Find the graphical merge tool that git-cli should prefer.
 ; pre    : The platform and git-cli configuration are available.
@@ -192,10 +294,13 @@
 ; result : The executable path, or #f.
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (find-mergetool-path)
-  (let ((configured (configured-mergetool))
+  (let ((tool (find-mergetool)))
-        (detected (detected-mergetool)))
+    (if tool
-    (if configured
+        (let loop ((tools (find-mergetools)))
-        #f
+          (cond
-        (if detected
+            ((null? tools) #f)
-            (cadr detected)
+            ((string=? tool (car (car tools)))
-            #f))))
+             (caddr (car tools)))
+            (else
+             (loop (cdr tools)))))
+        #f)))

scribblings/git-cli.scrbl

@@ -16,19 +16,39 @@ read credentials or other answers from the terminal.
 @section{Command interface}
 
 @defform[(git command argument ...)]{
-Runs a registered Git @racket[command]. The arguments are passed to the command.
+Runs a Git @racket[command]. When the command has a registered git-cli wrapper,
-Registered command symbols are @racket['init], @racket['status], @racket['add],
+that wrapper is used. Registered wrappers can provide structured Racket results,
-@racket['commit], @racket['push], @racket['pull], @racket['fetch],
+argument handling, or other command-specific behavior.
-@racket['config], @racket['branch], @racket['remote], @racket['stash], @racket['restore], @racket['reset], @racket['revert], @racket['rebase], @racket['merge], @racket['cherry-pick], @racket['mergetool], @racket['switch], @racket['clone],
+
-@racket['tag],
+Registered command symbols include @racket['init], @racket['status],
-@racket['log], @racket['rev-list], @racket['diff],
+@racket['add], @racket['commit], @racket['push], @racket['pull],
-@racket['show], @racket['grep], @racket['help], @racket['version], and
+@racket['fetch], @racket['config], @racket['branch], @racket['remote],
+@racket['stash], @racket['restore], @racket['reset], @racket['revert],
+@racket['rebase], @racket['merge], @racket['cherry-pick],
+@racket['mergetool], @racket['switch], @racket['clone], @racket['tag],
+@racket['log], @racket['rev-list], @racket['diff], @racket['show],
+@racket['grep], @racket['help], @racket['version], and
 @racket['new-version].
 
-Most registered commands invoke the Git command with the same name. Some
+When no wrapper is registered, the command and arguments are passed directly to
-commands process the result into a Racket value, such as @racket['status],
+the installed Git executable through @racket[run-git]. The result is handled by
-@racket['grep], @racket['log] with @tt{--list}, @racket['version], and
+the same standard result processing used by ordinary pass-through wrappers:
-@racket['new-version].
+normal Git output is displayed and a successful command returns @racket[#t];
+a non-zero exit status raises a git-cli error.
+
+This makes dedicated wrappers optional for Git commands where git-cli does not
+add useful behavior.
+
+@racketblock[
+(git 'blame "main.rkt")
+(git* clean -n)
+(git* worktree list)
+(git* archive --format=zip HEAD)
+]
+
+Some registered commands process the result into a Racket value, such as
+@racket['status], @racket['grep], @racket['log] with @tt{--list},
+@racket['version], and @racket['new-version].
 }
 
 
@@ -49,6 +69,9 @@ converted from its literal syntax.
 (git* switch (eval branch))
 ]
 
+Because @racket[git] falls back to direct Git execution for commands without a
+registered wrapper, @racket[git*] can also be used with those commands.
+
 @racket[gt] is retained as a compatibility alias for @racket[git*].
 }
 
@@ -183,6 +206,7 @@ The available editors can also be returned without prompting.
 
 @racketblock[
 (git* config editor --list)
+(git* config editor --downloads)
 ]
 
 Each item contains the short editor name, description, command and a boolean
@@ -193,6 +217,7 @@ be restored.
 
 @racketblock[
 (git* config editor vscode)
+(git* config editor notepad++)
 (git* config editor auto)
 ]
 
@@ -216,6 +241,49 @@ detected editor and returns its command. An exception is raised when no
 well-known GUI editor can be found.
 }
 
+@defproc[(editor-downloads) list?]{
+Returns official download pointers for optional GUI editors as
+@racket[(name description url)] items. No network request is performed.
+}
+
+On Windows, Notepad++ is detected both on @tt{PATH} and in the normal Program
+Files locations. git-cli invokes it with @tt{-multiInst -nosession}.
+
+@subsection{git-cli merge tool configuration}
+
+The @racket[git-config] procedure also recognizes the git-cli-specific
+@tt{mergetool} operation.
+
+@racketblock[
+(git* config mergetool)
+(git* config mergetool --list)
+(git* config mergetool --downloads)
+(git* config mergetool winmerge)
+(git* config mergetool auto)
+]
+
+With no additional argument an interactive selection is displayed.
+@tt{--list} returns @racket[(name description path current?)] items and
+@tt{--downloads} returns official download pointers. A detected merge tool can
+be selected by its short Git tool name. @tt{auto} clears the explicit git-cli
+selection and restores automatic detection.
+
+@defproc[(find-mergetools) list?]{
+Returns all well-known graphical merge tools found on the current platform as
+@racket[(name description path)] items.
+}
+
+@defproc[(mergetool-downloads) list?]{
+Returns official download pointers for optional merge tools as
+@racket[(name description url)] items. No network request is performed.
+}
+
+@defproc[(set-mergetool-auto!) string?]{
+Clears the explicit git-cli merge tool selection and returns the first
+automatically detected Git merge tool name. An exception is raised when no
+well-known merge tool can be found.
+}
+
 @defproc[(git-branch [argument any/c] ...) (or/c boolean? list?)]{
 Runs @tt{git branch} with the supplied arguments. This can be used to list,
 create, rename, or delete branches according to the options supported by the