stdin processing for run-git

private/git-provider.rkt

@@ -88,11 +88,13 @@
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; goal   : Run Git without allowing interactive terminal prompts.
-; pre    : args contains the Git command and its arguments.
-; post   : Standard output and error have been read completely.
+; pre    : args contains the Git command and its arguments; input is #f or a string
+;          that must be written to Git's standard input.
+; post   : Optional input has been written and standard output and error have been
+;          read completely.
 ; result : The exit code and ordered (source line) output items.
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-(define (run-git args)
+(define (run-git args #:input (input #f))
   (putenv "GIT_TERMINAL_PROMPT" "0")
   (let-values (((process stdout stdin stderr)
                 (apply subprocess
@@ -102,6 +104,9 @@
                        (git-exe)
                        (map (λ (arg) (format "~a" arg)) args)
                        )))
+    (when input
+      (display input stdin)
+      (flush-output stdin))
     (close-output-port stdin)
     (let ((output-channel (make-channel)))
         (define (read-output source port)