[lldb-dap] Don't send expanded descriptions for "hover" expressions (#92726)

VSCode will automatically ask for the children (in structured form) so
there's no point in sending the textual representation. This can make
displaying hover popups for complex variables with complicated data
formatters much faster. See discussion on #77026 for context.

Author: labath

lldb/test/API/tools/lldb-dap/evaluate/TestDAP_evaluate.py

@@ -27,7 +27,7 @@ def assertEvaluateFailure(self, expression):
         )
 
     def isResultExpandedDescription(self):
-        return self.context == "repl" or self.context == "hover"
+        return self.context == "repl"
 
     def isExpressionParsedExpected(self):
         return self.context != "hover"

lldb/test/API/tools/lldb-dap/variables/TestDAP_variables.py

@@ -502,29 +502,12 @@ def do_test_scopes_and_evaluate_expansion(self, enableAutoVariableSummaries: boo
                 },
                 "hover": {
                     "equals": {"type": "PointType"},
-                    "equals": {
-                        "result": """(PointType) pt = {
-  x = 11
-  y = 22
-  buffer = {
-    [0] = 0
-    [1] = 1
-    [2] = 2
-    [3] = 3
-    [4] = 4
-    [5] = 5
-    [6] = 6
-    [7] = 7
-    [8] = 8
-    [9] = 9
-    [10] = 10
-    [11] = 11
-    [12] = 12
-    [13] = 13
-    [14] = 14
-    [15] = 15
-  }
-}"""
+                    "startswith": {
+                        "result": (
+                            "{x:11, y:22, buffer:{...}}"
+                            if enableAutoVariableSummaries
+                            else "PointType @ 0x"
+                        )
                     },
                     "missing": ["indexedVariables"],
                     "hasVariablesReference": True,

lldb/tools/lldb-dap/JSONUtils.cpp

@@ -1065,9 +1065,9 @@ llvm::json::Object VariableDescription::GetVariableExtensionsJSON() {
 }
 
 std::string VariableDescription::GetResult(llvm::StringRef context) {
-  // In repl and hover context, the results can be displayed as multiple lines
-  // so more detailed descriptions can be returned.
-  if (context != "repl" && context != "hover")
+  // In repl context, the results can be displayed as multiple lines so more
+  // detailed descriptions can be returned.
+  if (context != "repl")
     return display_value;
 
   if (!v.IsValid())