[PATCH] gdb/DAP Few bug fixes & Evaluate Array Watch vars

[Simon Farre <simon.farre.cx@gmail.com>]

This patch fixes a few bugs.

First of all, name of VariableReferences must always be of string type.
This patch makes sure that this is the case by formatting the name. If
(when) the name is an integer, this will cause clients to fail or throw
errors.

Fixes a bug in NoOpArrayPrinter that calculated children to be N, but
only ever retrieves N-1 children, which makes Python at some time later
(during fetch_children -> fetch_one_child(N) ) raise an exception (out
of list index) which makes the entire request go bad.

The result[self.result_name] also f-strings the printer.to_string()
value, because this can potentially be a LazyString (which is a Python
object, not a string) and is not serializable by json.dumps.
---
 gdb/python/lib/gdb/dap/evaluate.py | 6 +++---
 gdb/python/lib/gdb/dap/varref.py   | 8 ++++++--
 gdb/python/lib/gdb/printing.py     | 2 +-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/gdb/python/lib/gdb/dap/evaluate.py b/gdb/python/lib/gdb/dap/evaluate.py
index af7bf43afd0..382ba00877f 100644
--- a/gdb/python/lib/gdb/dap/evaluate.py
+++ b/gdb/python/lib/gdb/dap/evaluate.py
@@ -26,8 +26,8 @@ from .varref import find_variable, VariableReference
 
 
 class EvaluateResult(VariableReference):
-    def __init__(self, value):
-        super().__init__(None, value, "result")
+    def __init__(self, expr, value):
+        super().__init__(expr, value, "result")
 
 
 # Helper function to evaluate an expression in a certain frame.
@@ -39,7 +39,7 @@ def _evaluate(expr, frame_id):
         frame.select()
         global_context = False
     val = gdb.parse_and_eval(expr, global_context=global_context)
-    ref = EvaluateResult(val)
+    ref = EvaluateResult(expr, val)
     return ref.to_object()
 
 
diff --git a/gdb/python/lib/gdb/dap/varref.py b/gdb/python/lib/gdb/dap/varref.py
index 23f18d647c3..9f6068b017e 100644
--- a/gdb/python/lib/gdb/dap/varref.py
+++ b/gdb/python/lib/gdb/dap/varref.py
@@ -66,7 +66,7 @@ class BaseReference:
             "variablesReference": self.ref,
         }
         if self.name is not None:
-            result["name"] = self.name
+            result["name"] = f"{self.name}"
         return result
 
     def no_children(self):
@@ -152,7 +152,11 @@ class VariableReference(BaseReference):
 
     def to_object(self):
         result = super().to_object()
-        result[self.result_name] = self.printer.to_string()
+        # If we're a primitive, gdb.Value f-strings just fine
+        # We also must f-string printer.to_string() as it can be a LazyString
+        result[self.result_name] = (
+            f"{self.value}" if self.ref == 0 else f"{self.printer.to_string()}"
+        )
         num_children = self.child_count()
         if num_children is not None:
             if (
diff --git a/gdb/python/lib/gdb/printing.py b/gdb/python/lib/gdb/printing.py
index ab62ef3e45c..353427d000a 100644
--- a/gdb/python/lib/gdb/printing.py
+++ b/gdb/python/lib/gdb/printing.py
@@ -298,7 +298,7 @@ class NoOpArrayPrinter:
         return "array"
 
     def children(self):
-        for i in range(self.low, self.high):
+        for i in range(self.low, self.high + 1):
             yield (i, self.value[i])
 
 
-- 
2.40.1