bug#55495: [PATCH] gnu: emacs-haskell-mode: Fix build.

[Taiju HIGASHI <higashi@taiju.info>]

Hi Liliana,

Thank you for reviewing!

>> index 529e9329d6..9d9669f383 100644
>> --- a/gnu/packages/emacs-xyz.scm
>> +++ b/gnu/packages/emacs-xyz.scm
>> @@ -1553,11 +1553,16 @@ (define-public emacs-haskell-mode
>>               (commit version)))
>>         (file-name (git-file-name name version))
>>         (sha256
>> -        (base32
>> "0zxbacqzr84krmhqpvzndnvlcjh1gs1x20ys0dykgd7chyhci5j5"))))
>> +        (base32
>> "0zxbacqzr84krmhqpvzndnvlcjh1gs1x20ys0dykgd7chyhci5j5"))
>> +        ;; Submitted for inclusion upstream.
>> +        ;; Not identical patches due to different target versions.
>> +        ;; (see: https://github.com/haskell/haskell-mode/pull/1780)
>> +       (patches
>> +        (search-patches "emacs-haskell-mode-fix-tests.patch"))))
>>      (propagated-inputs
>>       (list emacs-dash))
>>      (native-inputs
>> -     (list emacs-minimal emacs-el-search emacs-stream texinfo))
>> +     (list emacs-minimal emacs-el-search emacs-stream texinfo git))
> There are other ways of suppressing errors caused by git.  One of them
> would be to set vc-handled-backends to nil for the tests.

I have tried, but it does not work.
Is the following patch wrong?

diff --git a/gnu/packages/emacs-xyz.scm b/gnu/packages/emacs-xyz.scm
index 9d9669f383..1edfe2e754 100644
--- a/gnu/packages/emacs-xyz.scm
+++ b/gnu/packages/emacs-xyz.scm
@@ -1562,7 +1562,7 @@ (define-public emacs-haskell-mode
     (propagated-inputs
      (list emacs-dash))
     (native-inputs
-     (list emacs-minimal emacs-el-search emacs-stream texinfo git))
+     (list emacs-minimal emacs-el-search emacs-stream texinfo))
     (build-system gnu-build-system)
     (arguments
      (list
@@ -1577,6 +1577,11 @@ (define-public emacs-haskell-mode
                            (guix build emacs-utils))
       #:phases
       #~(modify-phases %standard-phases
+          (add-after 'unpack 'disable-vc-handled-backends
+                 (lambda _
+                   (substitute* "Makefile"
+                     (("\\(setq byte-compile-error-on-warn t\\)")
+                      "(setq byte-compile-error-on-warn t) (setq vc-handled-backends nil)"))))
           (delete 'configure)
           (add-before 'build 'pre-build
             (lambda* (#:key inputs #:allow-other-keys)