starlark: dict(None) and dict.update(None) are errors (google#129)

Fixes google#128
mikalv · Jan 30, 2019 · 367b72a · 367b72a
1 parent 2f3bb7c
commit 367b72a
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/starlark/library.go b/starlark/library.go
@@ -2178,8 +2178,6 @@ func string_find_impl(fnname string, s string, args Tuple, kwargs []Tuple, allow
 func updateDict(dict *Dict, updates Tuple, kwargs []Tuple) error {
 	if len(updates) == 1 {
 		switch updates := updates[0].(type) {
-		case NoneType:
-			// no-op
 		case IterableMapping:
 			// Iterate over dict's key/value pairs, not just keys.
 			for _, item := range updates.Items() {

diff --git a/starlark/testdata/dict.star b/starlark/testdata/dict.star
@@ -214,6 +214,10 @@ def test_delete():
 
 test_delete()
 
+# Regression test for github.com/google/starlark-go/issues/128.
+assert.fails(lambda: dict(None), 'got NoneType, want iterable')
+assert.fails(lambda: {}.update(None), 'got NoneType, want iterable')
+
 ---
 # Verify position of an "unhashable key" error in a dict literal.