Re: master ca47390: image-dired: Report when a necessary executable is not found

[Tino Calancha <tino.calancha@gmail.com>]

On Sun, 4 Sep 2016, Glenn Morris wrote:

>
> Hi,
>
>
> Tino Calancha wrote:
>
>>  (defcustom image-dired-cmd-create-thumbnail-program
>> -  "convert"
>> +  (executable-find "convert")
>>    "Executable used to create thumbnail.
>>  Used together with `image-dired-cmd-create-thumbnail-options'."
>>    :type 'string
>
> Please update this and all the other affected :types to allow for the
> nil values that may now occur. You might also want to document what a
> value of nil means. Thanks.
Please let me know if the following patch is OK:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
From e8d540387d92c64b971a31f372fd4627c5198948 Mon Sep 17 00:00:00 2001
From: Tino Calancha <tino.calancha@gmail.com>
Date: Mon, 5 Sep 2016 12:32:42 +0900
Subject: [PATCH] image-dired: Update :type declaration for several options

* lisp/image-dired.el (image-dired-cmd-create-thumbnail-program)
(image-dired-cmd-create-temp-image-program)
(image-dired-cmd-rotate-thumbnail-program)
(image-dired-cmd-rotate-original-program)
(image-dired-cmd-write-exif-data-program)
(image-dired-cmd-read-exif-data-program):
Update :type to allow for a nil value.
Mention in the doc string that if the value is nil, then
the function using this option signals an error.
---
  lisp/image-dired.el | 32 +++++++++++++++++++-------------
  1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/lisp/image-dired.el b/lisp/image-dired.el
index 5ac4600..eddaee1 100644
--- a/lisp/image-dired.el
+++ b/lisp/image-dired.el
@@ -224,10 +224,11 @@ image-dired-gallery-thumb-image-root-url
    :group 'image-dired)

  (defcustom image-dired-cmd-create-thumbnail-program
-  (executable-find "convert")
+  (when (executable-find "convert") "convert")
    "Executable used to create thumbnail.
+If nil, `image-dired-create-thumb' signals an error.
  Used together with `image-dired-cmd-create-thumbnail-options'."
-  :type 'string
+  :type '(choice (const :tag "Not Set" nil) string)
    :group 'image-dired)

  (defcustom image-dired-cmd-create-thumbnail-options
@@ -242,10 +243,11 @@ image-dired-cmd-create-thumbnail-options
    :group 'image-dired)

  (defcustom image-dired-cmd-create-temp-image-program
-  (executable-find "convert")
+  (when (executable-find "convert") "convert")
    "Executable used to create temporary image.
+If nil, `image-dired-display-image' signals an error.
  Used together with `image-dired-cmd-create-temp-image-options'."
-  :type 'string
+  :type '(choice (const :tag "Not Set" nil) string)
    :group 'image-dired)

  (defcustom image-dired-cmd-create-temp-image-options
@@ -308,10 +310,11 @@ image-dired-cmd-create-standard-thumbnail-command
    :group 'image-dired)

  (defcustom image-dired-cmd-rotate-thumbnail-program
-  (executable-find "mogrify")
+  (when (executable-find "mogrify") "mogrify")
    "Executable used to rotate thumbnail.
+If nil, `image-dired-rotate-thumbnail' signals an error.
  Used together with `image-dired-cmd-rotate-thumbnail-options'."
-  :type 'string
+  :type '(choice (const :tag "Not Set" nil) string)
    :group 'image-dired)

  (defcustom image-dired-cmd-rotate-thumbnail-options
@@ -326,11 +329,12 @@ image-dired-cmd-rotate-thumbnail-options
    :group 'image-dired)

  (defcustom image-dired-cmd-rotate-original-program
-  (cond ((executable-find "jpegtran"))
-        ((executable-find "convert")))
+  (cond ((executable-find "jpegtran") "jpegtran")
+        ((executable-find "convert") "convert"))
    "Executable used to rotate original image.
+If nil, `image-dired-rotate-original' signals an error.
  Used together with `image-dired-cmd-rotate-original-options'."
-  :type 'string
+  :type '(choice (const :tag "Not Set" nil) string)
    :group 'image-dired)

  (defcustom image-dired-cmd-rotate-original-options
@@ -364,10 +368,11 @@ image-dired-rotate-original-ask-before-overwrite
    :group 'image-dired)

  (defcustom image-dired-cmd-write-exif-data-program
-  (executable-find "exiftool")
+  (when (executable-find "exiftool") "exiftool")
    "Program used to write EXIF data to image.
+If nil, `image-dired-set-exif-data' signals an error.
  Used together with `image-dired-cmd-write-exif-data-options'."
-  :type 'string
+  :type '(choice (const :tag "Not Set" nil) string)
    :group 'image-dired)

  (defcustom image-dired-cmd-write-exif-data-options
@@ -381,10 +386,11 @@ image-dired-cmd-write-exif-data-options
    :group 'image-dired)

  (defcustom image-dired-cmd-read-exif-data-program
-  (executable-find "exiftool")
+  (when (executable-find "exiftool") "exiftool")
    "Program used to read EXIF data to image.
+If nil, `image-dired-get-exif-data' signals an error.
  Used together with `image-dired-cmd-read-exif-data-program-options'."
-  :type 'string
+  :type '(choice (const :tag "Not Set" nil) string)
    :group 'image-dired)

  (defcustom image-dired-cmd-read-exif-data-options
-- 
2.9.3


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;