[lldb/Interpreter] Add `interpreter.repeat-previous-command` setting

[mib]

Summary

This patch introduces a new interpreter setting to prevent LLDB from
re-executing the previous command when passing an empty command.

This can be very useful when performing actions that requires a long
time to complete.

To preserve the original behaviour, the setting defaults to true.

rdar://74983516

Signed-off-by: Med Ismail Bennani <[e-mail]>

[JDevlieghere]

LGTM

lldb/include/lldb/Interpreter/CommandInterpreter.h

public:
   void SetSaveSessionOnQuit(bool enable);
 
   bool GetEchoCommands() const;
   void SetEchoCommands(bool enable);
 
   bool GetEchoCommentCommands() const;
   void SetEchoCommentCommands(bool enable);
 
+  bool GetRepeatPreviousCommand() const;
+
   const CommandObject::CommandMap &GetUserCommands() const {
     return m_user_dict;
   }
 
   const CommandObject::CommandMap &GetCommands() const {
     return m_command_dict;
   }
 

lldb/source/Interpreter/CommandInterpreter.cpp

 }
 
 bool CommandInterpreter::GetSpaceReplPrompts() const {
   const uint32_t idx = ePropertySpaceReplPrompts;
   return m_collection_sp->GetPropertyAtIndexAsBoolean(
       nullptr, idx, g_interpreter_properties[idx].default_uint_value != 0);
 }
 
+bool CommandInterpreter::GetRepeatPreviousCommand() const {
+  const uint32_t idx = ePropertyRepeatPreviousCommand;
+  return m_collection_sp->GetPropertyAtIndexAsBoolean(
+      nullptr, idx, g_interpreter_properties[idx].default_uint_value != 0);
+}
+
 void CommandInterpreter::Initialize() {
   LLDB_SCOPED_TIMER();
 
   CommandReturnObject result(m_debugger.GetUseColor());
 
   LoadCommandDictionary();
 
   // An alias arguments vector to reuse - reset it before use...
else if (command_string[non_space] == CommandHistory::g_repeat_char) {
                                      command_string.c_str());
         result.SetStatus(eReturnStatusFailed);
         return false;
       }
     }
   }
 
   if (empty_command) {
+    if (!GetRepeatPreviousCommand()) {
+      result.SetStatus(eReturnStatusSuccessFinishNoResult);
+      return true;
+    }
+
     if (m_command_history.IsEmpty()) {
       result.AppendError("empty command");
       result.SetStatus(eReturnStatusFailed);
       return false;
     }
 
     command_line = m_repeat_command.c_str();
     command_string = command_line;

lldb/source/Interpreter/InterpreterProperties.td

let Definition = "interpreter" in {
   def EchoCommands: Property<"echo-commands", "Boolean">,
     Global,
     DefaultTrue,
     Desc<"If true, commands will be echoed before they are evaluated.">;
   def EchoCommentCommands: Property<"echo-comment-commands", "Boolean">,
     Global,
     DefaultTrue,
     Desc<"If true, commands will be echoed even if they are pure comment lines.">;
+  def RepeatPreviousCommand: Property<"repeat-previous-command", "Boolean">,
+    Global,
+    DefaultTrue,
+    Desc<"If true, LLDB will repeat the previous command if no command was passed to the interpreter. If false, LLDB won't repeat the previous command but only return a new prompt.">;
 }

lldb/test/API/commands/settings/TestSettings.py

class SettingsCommandTestCase(TestBase):
     def test_apropos_should_also_search_settings_description(self):
         """Test that 'apropos' command should also search descriptions for the settings variables."""
 
         self.expect("apropos 'environment variable'",
                     substrs=["target.env-vars",
                              "environment variables",
                              "executable's environment"])
 
+    def test_set_interpreter_repeat_prev_command(self):
+        """Test the `interpreter.repeat-previous-command` setting."""
+        self.build()
+
+        exe = self.getBuildArtifact("a.out")
+        self.runCmd("file " + exe, CURRENT_EXECUTABLE_SET)
+        setting = "interpreter.repeat-previous-command"
+
+        def cleanup(setting):
+            self.runCmd(
+                "settings clear %s" %
+                setting, check=False)
+
+        # Execute the cleanup function during test case tear down.
+        self.addTearDownHook(cleanup(setting))
+
+        # First, check for the setting default value.
+        self.expect("setting show %s" % setting,
+                    substrs=["interpreter.repeat-previous-command (boolean) = true"])
+
+        # Then, invert the setting, and check that was set correctly
+        self.runCmd("setting set %s false" % setting)
+        self.expect("setting show %s" % setting,
+                    substrs=["interpreter.repeat-previous-command (boolean) = false"])
+
+
+        ci  = self.dbg.GetCommandInterpreter()
+        self.assertTrue(ci.IsValid(), "Invalid command interpreter.")
+        # Now, test the functionnality
+        res = lldb.SBCommandReturnObject()
+        ci.HandleCommand('breakpoint set -n main', res)
+        self.assertTrue(res.Succeeded(), "Command failed.")
+        ci.HandleCommand('', res)
+        self.assertTrue(res.Succeeded(), "Empty command failed.")
+        self.assertEqual(self.dbg.GetSelectedTarget().GetNumBreakpoints(), 1)
+
     def test_append_target_env_vars(self):
         """Test that 'append target.run-args' works."""
         # Append the env-vars.
         self.runCmd('settings append target.env-vars MY_ENV_VAR=YES')
         # And add hooks to restore the settings during tearDown().
         self.addTearDownHook(
             lambda: self.runCmd("settings clear target.env-vars"))