[Lldb-commits] [lldb] Fix command escape bug in lldb-dap (PR #72902)

[via lldb-commits]

https://github.com/jeffreytan81 created https://github.com/llvm/llvm-project/pull/72902

https://github.com/llvm/llvm-project/pull/69238 caused breakage in VSCode debug console usage -- the user's input is always treated as commands instead of expressions (the same behavior as if empty command escape prefix is specified). 

The bug is in one overload of `GetString()` which did not respect the default value of "`". But more important, I am puzzled to find out why the regression is not caught by lldb test (testdap_evaluate). Turns out https://github.com/llvm/llvm-project/pull/69238 specifies commandEscapePrefix default value in test framework to be "`" while VSCode will default not specify any commandEscapePrefix at all. Changing it to None will fail `testdap_evaluate`. We should align the default behavior between DAP client and testcase. 

This patches fixes the bug in `GetString()` and changed the default value of commandEscapePrefix in testcases to be None (be consistent with IDE). 

>From 2838929d255642942dfe33d6584d0486d026f926 Mon Sep 17 00:00:00 2001
From: jeffreytan81 <jeffreytan at fb.com>
Date: Mon, 20 Nov 2023 10:54:39 -0800
Subject: [PATCH] Fix command escape bug in lldb-dap

---
 .../Python/lldbsuite/test/tools/lldb-dap/dap_server.py        | 2 +-
 .../Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py  | 4 ++--
 lldb/tools/lldb-dap/JSONUtils.cpp                             | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
index 518e3b9cf5bab33..bb863bb87191763 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
+++ b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
@@ -731,7 +731,7 @@ def request_launch(
         postRunCommands=None,
         enableAutoVariableSummaries=False,
         enableSyntheticChildDebugging=False,
-        commandEscapePrefix="`",
+        commandEscapePrefix=None,
         customFrameFormat=None,
         customThreadFormat=None,
     ):
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
index 0cf9d4fde49488f..4ccd6014e54be6a 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
+++ b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/lldbdap_testcase.py
@@ -354,7 +354,7 @@ def launch(
         postRunCommands=None,
         enableAutoVariableSummaries=False,
         enableSyntheticChildDebugging=False,
-        commandEscapePrefix="`",
+        commandEscapePrefix=None,
         customFrameFormat=None,
         customThreadFormat=None,
     ):
@@ -434,7 +434,7 @@ def build_and_launch(
         lldbDAPEnv=None,
         enableAutoVariableSummaries=False,
         enableSyntheticChildDebugging=False,
-        commandEscapePrefix="`",
+        commandEscapePrefix=None,
         customFrameFormat=None,
         customThreadFormat=None,
     ):
diff --git a/lldb/tools/lldb-dap/JSONUtils.cpp b/lldb/tools/lldb-dap/JSONUtils.cpp
index 50ade02801529c3..03a43f9da87f241 100644
--- a/lldb/tools/lldb-dap/JSONUtils.cpp
+++ b/lldb/tools/lldb-dap/JSONUtils.cpp
@@ -57,7 +57,7 @@ llvm::StringRef GetString(const llvm::json::Object *obj, llvm::StringRef key,
                           llvm::StringRef defaultValue) {
   if (obj == nullptr)
     return defaultValue;
-  return GetString(*obj, key);
+  return GetString(*obj, key, defaultValue);
 }
 
 // Gets an unsigned integer from a JSON object using the key, or returns the