Allow minibuffer prompts to use faces

* doc/lispref/minibuf.texi (Text from Minibuffer): Document
`minibuffer-prompt-properties' and explain how faces work in
the minibuffer prompt.

* src/minibuf.c (read_minibuf): If `face' is in
`minibuffer-prompt-properties', apply it to the end of the
face list to allow users to have their own faces on the
prompts (bug#16136).

3 files changed, 48 insertions, 2 deletions

diff --git a/doc/lispref/minibuf.texi b/doc/lispref/minibuf.texi
index 6f41090ebea..88662aba08a 100644
--- a/doc/lispref/minibuf.texi
+++ b/doc/lispref/minibuf.texi
@@ -170,6 +170,23 @@ non-@code{nil}, then the string that is returned includes whatever text
 properties were present in the minibuffer.  Otherwise all the text
 properties are stripped when the value is returned.
 
+@cvindex minibuffer-prompt-properties
+The text properties in @code{minibuffer-prompt-properties} are applied
+to the prompt.  By default, this property list defines a face to use
+for the prompt.  This face, if present, is applied to the end of the
+face list and merged before display.
+
+If the user wants to completely control the look of the prompt, the
+most convenient way to do that is to specify the @code{default} face
+at the end of all face lists.  For instance:
+
+@lisp
+(read-from-minibuffer
+ (concat
+  (propertize "Bold" 'face '(bold default))
+  (propertize " and normal: " 'face '(default))))
+@end lisp
+
 If the argument @var{inherit-input-method} is non-@code{nil}, then the
 minibuffer inherits the current input method (@pxref{Input Methods}) and
 the setting of @code{enable-multibyte-characters} (@pxref{Text
diff --git a/etc/NEWS b/etc/NEWS
index ed4810b2982..cf360a329a2 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -57,6 +57,12 @@ affected by this, as SGI stopped supporting IRIX in December 2013.
 * Changes in Emacs 25.2
 
 +++
+** Faces in `minibuffer-prompt-properties' no longer overwrite properties
+in the text in functions like `read-from-minibuffer', but instead are
+added to the end of the face list.  This allows users to say things
+like `(read-from-minibuffer (propertize "Enter something: " 'face 'bold))'.
+
++++
 ** The new variable `extended-command-suggest-shorter' has been added
 to control whether to suggest shorter `M-x' commands or not.
 
diff --git a/src/minibuf.c b/src/minibuf.c
index 0b8b00ce2c9..d2a4c9b9538 100644
--- a/src/minibuf.c
+++ b/src/minibuf.c
@@ -630,8 +630,31 @@ read_minibuf (Lisp_Object map, Lisp_Object initial, Lisp_Object prompt,
                             Qrear_nonsticky, Qt, Qnil);
         Fput_text_property (make_number (BEG), make_number (PT),
                             Qfield, Qt, Qnil);
-        Fadd_text_properties (make_number (BEG), make_number (PT),
-                              Vminibuffer_prompt_properties, Qnil);
+        if (Fconsp (Vminibuffer_prompt_properties))
+          {
+            /* We want to apply all properties from
+               `minibuffer-prompt-properties' to the region normally,
+               but if the `face' property is present, add that
+               property to the end of the face properties to avoid
+               overwriting faces. */
+            Lisp_Object list = Vminibuffer_prompt_properties;
+            while (CONSP (list))
+              {
+                Lisp_Object key = XCAR (list);
+                list = XCDR (list);
+                if (CONSP (list))
+                  {
+                    Lisp_Object val = XCAR (list);
+                    list = XCDR (list);
+                    if (EQ (key, Qface))
+                      Fadd_face_text_property (make_number (BEG),
+                                               make_number (PT), val, Qt, Qnil);
+                    else
+                      Fput_text_property (make_number (BEG), make_number (PT),
+                                          key, val, Qnil);
+                  }
+              }
+          }
       }
     unbind_to (count1, Qnil);
   }