[gtk/issue-2923] Annotate the expression array as "nullable"

[Emmanuele Bassi <ebassi src gnome org>]

commit 595cc929e69c1c3e44c0f59a04d9b3f169463545
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Sep 14 17:00:23 2020 +0100

    Annotate the expression array as "nullable"
    
    While it's a bit dubious whether array+length annotations should be
    marked as "nullable", we do this elsewhere in the API, so might as well
    be consistent.
    
    In practice, the array argument is only ever allowed to be NULL iff the
    length argument is 0; annotations are static, so if somebody decides to
    pass a NULL argument with a non-zero value, they will get a run time
    critical error, instead of a compile time one, which is somewhat counter
    to the point of annotating the API in the first place.
    
    Fixes: #2923

 gtk/gtkexpression.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkexpression.c b/gtk/gtkexpression.c
index 574274ea7e..009c2da8c7 100644
--- a/gtk/gtkexpression.c
+++ b/gtk/gtkexpression.c
@@ -1577,7 +1577,7 @@ GTK_DEFINE_EXPRESSION_TYPE (GtkClosureExpression,
  * @value_type: the type of the value that this expression evaluates to
  * @closure: closure to call when evaluating this expression. If closure is floating, it is adopted
  * @n_params: the number of params needed for evaluating @closure
- * @params: (array length=n_params) (transfer full): expressions for each parameter
+ * @params: (nullable) (array length=n_params) (transfer full): expressions for each parameter
  *
  * Creates a GtkExpression that calls @closure when it is evaluated.
  * @closure is called with the @this object and the results of evaluating