stdin processing for run-git

README.md

@@ -49,3 +49,17 @@ Most are also exported as direct procedures such as `git-status`, `git-add`,
 `git-fetch`, `git-switch`, `git-tag`, `git-log`, `git-diff`, and `git-show`.
 
 See the Scribble documentation for command-specific behavior and return values.
+
+## Low-level Git execution
+
+`run-git` can be used when direct access to Git's stdin/stdout protocol is
+needed. Optional text can be supplied to Git with `#:input`.
+
+```racket
+(run-git '(credential fill)
+         #:input "protocol=https\nhost=git.dijkewijk.nl\n\n")
+```
+
+The result remains two values: Git's exit code and the ordered
+`(source line)` output items.
+

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.
+; pre    : args contains the Git command and its arguments; input is #f or a string
-; post   : Standard output and error have been read completely.
+;          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)

scribblings/git.scrbl

@@ -251,3 +251,21 @@ Updates the version in @filepath{info.rkt}. The kind is @racket['major],
 @racket['minor], or @racket['patch], with @racket['maj] and @racket['min] as
 abbreviations. The result is the new version as a list of three integers.
 }
+
+
+@section{Low-level Git execution}
+
+@defproc[(run-git [args list?]
+                  [#:input input (or/c #f string?) #f])
+         (values exact-integer? list?)]{
+Runs Git without interactive terminal prompts. When @racket[input] is a string,
+it is written to Git's standard input before that input port is closed.
+
+The procedure returns two values: Git's exit code and the ordered output items,
+where each item identifies either @racket['stdout] or @racket['stderr].
+
+@racketblock[
+(run-git '(credential fill)
+         #:input "protocol=https\nhost=git.dijkewijk.nl\n\n")
+]
+}