Test case: Typing into the entry generates events even though it can contain only one character.

// gcc -g -Wall test.c -o test `pkg-config --cflags --libs gtk+-3.0`

#include <gtk/gtk.h>

static void
changed_cb ()
{
    g_printerr ("!\n");
}

int main (int argc, char **argv)
{
    gtk_init (&argc, &argv);

    GtkWidget *w = gtk_window_new (GTK_WINDOW_TOPLEVEL);

    GtkWidget *e = gtk_entry_new ();
    gtk_entry_set_max_length (GTK_ENTRY (e), 1);
    g_signal_connect (e, "changed", G_CALLBACK (changed_cb), NULL);
    gtk_container_add (GTK_CONTAINER (w), e);

    gtk_widget_show_all (w);

    gtk_main ();

    return 0;
}

This was found when using a GtkSearchEntry. This entry was connected to a server based query and due to some input error (a cat on the keyboard?) it sent an enormous number of queries to the server. We proposed limiting the length of the search entry, but due to the described bug it would continue to generate queries even once it hits the limit.

Created attachment 351845 [details] [review]
EntryBuffer: Don't generate changed events when input is truncated

There seems to be two places where this could be done:
a) gtk_entry_buffer_insert_text() - ignore user input if it ends up with length zero (i.e. this patch)
b) gtk_entry_buffer_normal_insert_text() - after the text is processed and possibly overridable? (can't think of a use case).

Review of attachment 351845 [details] [review]:

Looks fine to me

Fixed in master and gnome-3-22

that should say gtk-3-22