patch 8.1.1388: errors when calling prop_remove() for an unloaded buffer

Problem:    Errors when calling prop_remove() for an unloaded buffer.
Solution:   Bail out when the buffer is not loaded.  Add a few more tests for
            failing when the buffer number is invalid.

src/testdir/test_textprop.vim

@@ -69,6 +69,8 @@ func Test_proptype_buf()
   call assert_equal(1, len(prop_type_list({'bufnr': bufnr})))
   call prop_type_delete('two', {'bufnr': bufnr})
   call assert_equal(0, len(prop_type_list({'bufnr': bufnr})))
+
+  call assert_fails("call prop_type_add('one', {'bufnr': 98764})", "E158:")
 endfunc
 
 func AddPropTypes()
@@ -124,6 +126,8 @@ func Test_prop_add()
   let expected = [{'col': 5, 'length': 0, 'type': 'two', 'id': 0, 'start': 1, 'end': 1}]
   call assert_equal(expected, prop_list(1))
 
+  call assert_fails("call prop_add(1, 5, {'type': 'two', 'bufnr': 234343})", 'E158:')
+
   call DeletePropTypes()
   bwipe!
 endfunc
@@ -136,15 +140,18 @@ func Test_prop_remove()
   call assert_equal(props, prop_list(1))
 
   " remove by id
-  call prop_remove({'id': 12}, 1)
+  call assert_equal(1, prop_remove({'id': 12}, 1))
   unlet props[2]
   call assert_equal(props, prop_list(1))
 
   " remove by type
-  call prop_remove({'type': 'one'}, 1)
+  call assert_equal(1, prop_remove({'type': 'one'}, 1))
   unlet props[1]
   call assert_equal(props, prop_list(1))
 
+  " remove from unknown buffer
+  call assert_fails("call prop_remove({'type': 'one', 'bufnr': 123456}, 1)", 'E158:')
+
   call DeletePropTypes()
   bwipe!
 endfunc
@@ -760,3 +767,16 @@ func Test_textprop_empty_buffer()
   call prop_add(1, 1, {'type': 'comment'})
   close
 endfunc
+
+func Test_textprop_remove_from_buf()
+  new
+  let buf = bufnr('')
+  call prop_type_add('one', {'bufnr': buf})
+  call prop_add(1, 1, {'type': 'one', 'id': 234})
+  file x
+  edit y
+  call prop_remove({'id': 234, 'bufnr': buf}, 1)
+  call prop_type_delete('one', {'bufnr': buf})
+  bwipe! x
+  close
+endfunc

src/textprop.c

@@ -129,7 +129,7 @@ get_bufnr_from_arg(typval_T *arg, buf_T **buf)
     di = dict_find(arg->vval.v_dict, (char_u *)"bufnr", -1);
     if (di != NULL)
     {
-	*buf = tv_get_buf(&di->di_tv, FALSE);
+	*buf = get_buf_arg(&di->di_tv);
 	if (*buf == NULL)
 	    return FAIL;
     }
@@ -560,13 +560,10 @@ f_prop_remove(typval_T *argvars, typval_T *rettv)
     }
 
     dict = argvars[0].vval.v_dict;
-    di = dict_find(dict, (char_u *)"bufnr", -1);
+    if (get_bufnr_from_arg(&argvars[0], &buf) == FAIL)
-    if (di != NULL)
+	return;
-    {
+    if (buf->b_ml.ml_mfp == NULL)
-	buf = tv_get_buf(&di->di_tv, FALSE);
-	if (buf == NULL)
 	return;
-    }
 
     di = dict_find(dict, (char_u*)"all", -1);
     if (di != NULL)

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1388,
 /**/
     1387,
 /**/