patch 8.1.0515: reloading a script gives errors for existing functions
Problem: Reloading a script gives errors for existing functions.
Solution: Allow redefining a function once when reloading a script.
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index ac8a27f..d942d07 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -1138,3 +1138,30 @@
call delete('Xfuncrange2')
bwipe!
endfunc
+
+func Test_func_exists_on_reload()
+ call writefile(['func ExistingFunction()', 'echo "yes"', 'endfunc'], 'Xfuncexists')
+ call assert_equal(0, exists('*ExistingFunction'))
+ source Xfuncexists
+ call assert_equal(1, exists('*ExistingFunction'))
+ " Redefining a function when reloading a script is OK.
+ source Xfuncexists
+ call assert_equal(1, exists('*ExistingFunction'))
+
+ " But redefining in another script is not OK.
+ call writefile(['func ExistingFunction()', 'echo "yes"', 'endfunc'], 'Xfuncexists2')
+ call assert_fails('source Xfuncexists2', 'E122:')
+
+ delfunc ExistingFunction
+ call assert_equal(0, exists('*ExistingFunction'))
+ call writefile([
+ \ 'func ExistingFunction()', 'echo "yes"', 'endfunc',
+ \ 'func ExistingFunction()', 'echo "no"', 'endfunc',
+ \ ], 'Xfuncexists')
+ call assert_fails('source Xfuncexists', 'E122:')
+ call assert_equal(1, exists('*ExistingFunction'))
+
+ call delete('Xfuncexists2')
+ call delete('Xfuncexists')
+ delfunc ExistingFunction
+endfunc