master d4e436e 3/5: Merge from origin/emacs-27

[Glenn Morris]

branch: master
commit d4e436e080e2157b7bc3353ca8d1cfcf1e17c79c
Merge: 3d14ec5 ac1a2b2
Author: Glenn Morris <rgm@gnu.org>
Commit: Glenn Morris <rgm@gnu.org>

    Merge from origin/emacs-27
    
    ac1a2b2160 Add more doc-view requirements
    109eb1e7e2 Fix undefined behavior when fetching glyphs from the displ...
    
    # Conflicts:
    #   lisp/doc-view.el
---
 lisp/doc-view.el | 10 ++++++----
 src/xdisp.c      |  6 +++---
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/lisp/doc-view.el b/lisp/doc-view.el
index 73483b2..9997c1a 100644
--- a/lisp/doc-view.el
+++ b/lisp/doc-view.el
@@ -22,10 +22,12 @@
 
 ;;; Requirements:
 
-;; doc-view.el requires GNU Emacs 22.1 or newer.  You also need Ghostscript,
-;; `dvipdf' (comes with Ghostscript) or `dvipdfm' (comes with teTeX or TeXLive)
-;; and `pdftotext', which comes with xpdf (https://www.foolabs.com/xpdf/) or
-;; poppler (https://poppler.freedesktop.org/).
+;; Viewing PS/PDF/DVI files requires Ghostscript, `dvipdf' (comes with
+;; Ghostscript) or `dvipdfm' (comes with teTeX or TeXLive) and
+;; `pdftotext', which comes with xpdf (https://www.foolabs.com/xpdf/)
+;; or poppler (https://poppler.freedesktop.org/).
+;; Djvu documents require `ddjvu' (from DjVuLibre).
+;; ODF files require `soffice' (from LibreOffice).
 
 ;;; Commentary:
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 32486ea..2344fe7 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -8324,10 +8324,10 @@ next_element_from_display_vector (struct it *it)
            next_face_id = it->dpvec_face_id;
          else
            {
-             int lface_id =
-               GLYPH_CODE_FACE (it->dpvec[it->current.dpvec_index + 1]);
+              Lisp_Object gc = it->dpvec[it->current.dpvec_index + 1];
+              int lface_id = GLYPH_CODE_P (gc) ? GLYPH_CODE_FACE (gc) : 0;
 
-             if (lface_id > 0)
+              if (lface_id > 0)
                next_face_id = merge_faces (it->w, Qt, lface_id,
                                            it->saved_face_id);
            }