__get_cword: avoid $index < 0 (Alioth: #315107)

Modified-by: Ville Skyttä <ville.skytta@iki.fi>
Signed-off-by: Ondrej Oprala <ooprala@redhat.com>

bash_completion

@@ -320,8 +320,8 @@ __get_cword_at_cursor_by_ref()
             ]]; do
                 # Strip first character
                 cur="${cur:1}"
-                # Decrease cursor position
-                ((index--))
+                # Decrease cursor position, staying >= 0
+                [[ $index -gt 0 ]] && ((index--))
             done
 
             # Does found word match cword?
@@ -450,8 +450,8 @@ _get_cword()
             ]]; do
                 # Strip first character
                 cur="${cur:1}"
-                # Decrease cursor position
-                ((index--))
+                # Decrease cursor position, staying >= 0
+                [[ $index -gt 0 ]] && ((index--))
             done
 
             # Does found word matches cword?

test/unit/_get_cword.exp

@@ -249,4 +249,18 @@ expect {
 sync_after_int
 
 
+set test "index shouldn't drop below 0"
+set dir $::srcdir/fixtures/_get_cword
+set cmd "scp"
+send "$cmd ääää§ se\t\r\n"
+expect {
+    -re "index: substring expression < 0" { fail "$test" }
+    -re /@ { pass "$test" }
+    default { unresolved "$test" }
+}
+
+
+sync_after_int
+
+
 teardown