(verify_interval_modification): For insertion in

middle of an interval, use the same criterion as between intervals
for whether read-only forbids it.

diff --git a/src/intervals.c b/src/intervals.c
index 6c7ce7ee898be208050f00f06bd9624a7c8dead4..597fcf07b303d2fe7ed129251b778103e2c56718 100644 (file)
--- a/src/intervals.c
+++ b/src/intervals.c
@@ -1847,8 +1847,7 @@ verify_interval_modification (buf, start, end)
                        error ("Attempt to insert within read-only text");
                    }
                }
-             else
-               after = Qnil;
+
              if (! NULL_INTERVAL_P (prev))
                {
                  before = textget (prev->plist, Qread_only);
@@ -1868,18 +1867,30 @@ verify_interval_modification (buf, start, end)
                        error ("Attempt to insert within read-only text");
                    }
                }
-             else
-               before = Qnil;
            }
          else if (! NULL_INTERVAL_P (i))
-           before = after = textget (i->plist, Qread_only);
-         if (! NULL_INTERVAL_P (i) && ! NULL_INTERVAL_P (prev))
            {
-             /* If I and PREV differ, neither of them has a sticky
-                read-only property. It only remains to check, whether
-                they have a common read-only property.  */
-             if (! NILP (before) && EQ (before, after))
-               error ("Attempt to insert within read-only text");
+             after = textget (i->plist, Qread_only);
+                 
+             /* If interval I is read-only and read-only is
+                front-sticky, inhibit insertion.
+                Check for read-only as well as category.  */
+             if (! NILP (after) && NILP (Fmemq (after, Vinhibit_read_only)))
+               {
+                 Lisp_Object tem;
+
+                 tem = textget (i->plist, Qfront_sticky);
+                 if (TMEM (Qread_only, tem)
+                     || (NILP (textget_direct (i->plist, Qread_only))
+                         && TMEM (Qcategory, tem)))
+                   error ("Attempt to insert within read-only text");
+
+                 tem = textget (prev->plist, Qrear_nonsticky);
+                 if (! TMEM (Qread_only, tem)
+                     && (! NILP (textget_direct (prev->plist, Qread_only))
+                         || ! TMEM (Qcategory, tem)))
+                   error ("Attempt to insert within read-only text");
+               }
            }
        }