Run 'become' only when the command template is properly evaluated

src/terminal.go

@@ -2863,7 +2863,8 @@ func (t *Terminal) Loop() {
 			switch a.t {
 			case actIgnore:
 			case actBecome:
-				_, list := t.buildPlusList(a.a, false)
+				valid, list := t.buildPlusList(a.a, false)
+				if valid {
 					command := t.replacePlaceholder(a.a, false, string(t.input), list)
 					shell := os.Getenv("SHELL")
 					if len(shell) == 0 {
@@ -2877,6 +2878,7 @@ func (t *Terminal) Loop() {
 						}
 						syscall.Exec(shellPath, []string{shell, "-c", command}, os.Environ())
 					}
+				}
 			case actExecute, actExecuteSilent:
 				t.executeCommand(a.a, false, a.t == actExecuteSilent, false)
 			case actExecuteMulti:

test/test_go.rb

@@ -2645,10 +2645,16 @@ class TestGoFZF < TestBase
   end
 
   def test_become
-    tmux.send_keys "seq 10 | #{FZF} --bind 'enter:become:seq 100 | #{FZF}'", :Enter
+    tmux.send_keys "seq 100 | #{FZF} --bind 'enter:become:seq {} | #{FZF}'", :Enter
-    tmux.until { |lines| assert_equal 10, lines.item_count }
-    tmux.send_keys :Enter
     tmux.until { |lines| assert_equal 100, lines.item_count }
+    tmux.send_keys 999
+    tmux.until { |lines| assert_equal 0, lines.match_count }
+    tmux.send_keys :Enter
+    tmux.until { |lines| assert_equal 0, lines.match_count }
+    tmux.send_keys :BSpace
+    tmux.until { |lines| assert_equal 1, lines.match_count }
+    tmux.send_keys :Enter
+    tmux.until { |lines| assert_equal 99, lines.item_count }
   end
 end