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[Dynamic instrumentation] DEBUG-3374 support @key and @value in EL hash iteration #8511

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Merged
dudikeleti merged 2 commits into from
Apr 28, 2026
Merged

[Dynamic instrumentation] DEBUG-3374 support @key and @value in EL hash iteration #8511

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01153bf
support @key and @value in EL hash iteration
dudikeleti Apr 23, 2026
5b2d11a
support non generic dictionary
dudikeleti Apr 28, 2026
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87 changes: 72 additions & 15 deletions tracer/src/Datadog.Trace/Debugger/Expressions/ProbeExpressionParser.Collection.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -47,23 +47,12 @@ private Expression Predicate(JsonTextReader reader, List<ParameterExpression> pa
ReturnDefaultValueExpression();
}

if (!IsSafeCollection(source.Type))
if (!IsSafeCollection(source.Type) && !IsSafeNonGenericDictionary(source.Type))
{
throw new InvalidOperationException("Source must be an array or implement ICollection or IReadOnlyCollection");
throw new InvalidOperationException("Source must be an array or implement ICollection, IReadOnlyCollection, or IDictionary");
}

Type itParameterType = null;
if (source.Type.IsArray)
{
itParameterType = source.Type.GetElementType();
}
else
{
if (source.Type.GetGenericArguments().Length > 0)
{
itParameterType = source.Type.GetGenericArguments()[0];
}
}
var itParameterType = GetIteratorParameterType(source.Type);

if (predicateMethod == null)
{
Expand All @@ -74,7 +63,7 @@ private Expression Predicate(JsonTextReader reader, List<ParameterExpression> pa
var predicate = ParseTree(reader, new List<ParameterExpression> { Expression.Parameter(source.Type) }, itParameter);
var lambda = Expression.Lambda(predicate, itParameter);
var genericPredicateMethod = predicateMethod.MakeGenericMethod(itParameterType);
callExpression = Expression.Call(null, genericPredicateMethod, source, lambda);
callExpression = Expression.Call(null, genericPredicateMethod, PredicateSource(source, itParameterType), lambda);
if (IsIEnumerable(callExpression.Type))
{
var toListMethod = ProbeExpressionParserHelper.GetMethodByReflection(typeof(Enumerable), nameof(Enumerable.ToList), null);
Expand Down Expand Up @@ -215,6 +204,69 @@ private MethodCallExpression CollectionAndStringLengthExpression(Expression sour
return Expression.Call(source, countOrLength);
}

private Type GetIteratorParameterType(Type sourceType)
{
if (sourceType.IsArray)
{
return sourceType.GetElementType();
}

var genericDictionaryType = sourceType.IsGenericType && sourceType.GetGenericTypeDefinition() == typeof(IDictionary<,>)
? sourceType
: sourceType.GetInterfaces().FirstOrDefault(i => i.IsGenericType && i.GetGenericTypeDefinition() == typeof(IDictionary<,>));

if (genericDictionaryType != null)
{
return typeof(KeyValuePair<,>).MakeGenericType(genericDictionaryType.GetGenericArguments());
}

if (typeof(IDictionary).IsAssignableFrom(sourceType))
{
return typeof(DictionaryEntry);
}
Comment on lines +223 to +226

@chatgpt-codex-connector chatgpt-codex-connector Bot Apr 23, 2026

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P2 Badge Handle non-generic dictionaries in the predicate path

For non-generic dictionary inputs such as Hashtable/IDictionary, this new branch is never reached: Predicate first rejects the source with IsSafeCollection, and IsCollection only recognizes generic collection interfaces. That means any(ref HashtableLocal, { @key == ... }) is compiled as a default-true condition with an error instead of evaluating the entries, despite the added DictionaryEntry path; the source also needs to be allowed/cast into an IEnumerable<DictionaryEntry> path before invoking LINQ.

Useful? React with 👍 / 👎.

@dudikeleti dudikeleti Apr 28, 2026

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5b2d11a


var enumerableType = sourceType.IsGenericType && sourceType.GetGenericTypeDefinition() == typeof(IEnumerable<>)
? sourceType
: sourceType.GetInterfaces().FirstOrDefault(i => i.IsGenericType && i.GetGenericTypeDefinition() == typeof(IEnumerable<>));

if (enumerableType != null)
{
return enumerableType.GetGenericArguments()[0];
}

throw new InvalidOperationException("Fail to determined the iterator parameter type");
}

private Expression PredicateSource(Expression source, Type itParameterType)
{
if (itParameterType != typeof(DictionaryEntry) || !IsSafeNonGenericDictionary(source.Type))
{
return source;
}

var castMethod = ProbeExpressionParserHelper.GetMethodByReflection(typeof(Enumerable), nameof(Enumerable.Cast), [typeof(IEnumerable)], [typeof(DictionaryEntry)]);
return Expression.Call(null, castMethod, source);
}

private bool TryGetCollectionIteratorProperty(ParameterExpression itParameter, string propertyName, out MemberExpression propertyExpression)
{
propertyExpression = null;

if (itParameter.Type == typeof(DictionaryEntry))
{
propertyExpression = Expression.Property(itParameter, propertyName);
return true;
}

if (itParameter.Type.IsGenericType && itParameter.Type.GetGenericTypeDefinition() == typeof(KeyValuePair<,>))
{
propertyExpression = Expression.Property(itParameter, propertyName);
return true;
}

return false;
}

private bool IsSafeCollection(Type type)
{
if (type == null)
Expand All @@ -225,6 +277,11 @@ private bool IsSafeCollection(Type type)
return type.IsArray || (IsMicrosoftType(type) && IsCollection(type));
}

private bool IsSafeNonGenericDictionary(Type type)
{
return type != null && IsMicrosoftType(type) && typeof(IDictionary).IsAssignableFrom(type);
}

private bool IsIEnumerable(Type type)
{
return IsSafeCollection(type) || type.GetInterface(nameof(IEnumerable)) != null;
Expand Down
55 changes: 46 additions & 9 deletions tracer/src/Datadog.Trace/Debugger/Expressions/ProbeExpressionParser.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,8 @@ internal partial class ProbeExpressionParser<T>
private const string @Exceptions = "@exception";
private const string @Duration = "@duration";
private const string @It = "@it";
private const string @Key = "@key";
private const string @Value = "@value";
private const string @This = "this";

private static readonly IDatadogLogger Log = DatadogLogging.GetLoggerFor(typeof(ProbeExpressionParser<T>));
Expand Down Expand Up @@ -55,7 +57,8 @@ static ProbeExpressionParser()

private Expression ParseRoot(
JsonTextReader reader,
List<ParameterExpression> parameters)
List<ParameterExpression> parameters,
ParameterExpression itParameter = null)
{
var readerValue = reader.Value?.ToString();
switch (reader.TokenType)
Expand All @@ -65,27 +68,27 @@ private Expression ParseRoot(
{
case "and":
{
return ConditionalOperator(reader, Expression.AndAlso, parameters);
return ConditionalOperator(reader, Expression.AndAlso, parameters, itParameter);
}

case "or":
{
return ConditionalOperator(reader, Expression.OrElse, parameters);
return ConditionalOperator(reader, Expression.OrElse, parameters, itParameter);
}

default:
return ParseTree(reader, parameters, null, false);
return ParseTree(reader, parameters, itParameter, false);
}
}

return null;
}

private Expression ConditionalOperator(JsonTextReader reader, Combiner combiner, List<ParameterExpression> parameters)
private Expression ConditionalOperator(JsonTextReader reader, Combiner combiner, List<ParameterExpression> parameters, ParameterExpression itParameter)
{
_arrayStack++;
reader.Read();
var right = ParseTree(reader, parameters, null);
var right = ParseTree(reader, parameters, itParameter);
var left = Combine(null, right, combiner);

while (reader.Read())
Expand All @@ -111,7 +114,7 @@ private Expression ConditionalOperator(JsonTextReader reader, Combiner combiner,
break;
}

right = ParseTree(reader, parameters, null, false);
right = ParseTree(reader, parameters, itParameter, false);
left = Combine(left, right, combiner);
}

Expand Down Expand Up @@ -153,14 +156,14 @@ private Expression ParseTree(
case "and":
case "&&":
{
var right = ParseRoot(reader, parameters);
var right = ParseRoot(reader, parameters, itParameter);
return right;
}

case "or":
case "||":
{
var right = ParseRoot(reader, parameters);
var right = ParseRoot(reader, parameters, itParameter);
return right;
}

Expand Down Expand Up @@ -358,6 +361,40 @@ private Expression ParseTree(
return itParameter;
}

if (readerValue == Key)
{
if (itParameter == null)
{
AddError(readerValue, "current item in iterator is null");
return UndefinedValue();
}

if (TryGetCollectionIteratorProperty(itParameter, nameof(KeyValuePair<int, int>.Key), out var keyExpression))
{
return keyExpression;
}

AddError(readerValue, $"{readerValue} is only supported when iterating over dictionary entries");
return UndefinedValue();
}

if (readerValue == Value)
{
if (itParameter == null)
{
AddError(readerValue, "current item in iterator is null");
return UndefinedValue();
}

if (TryGetCollectionIteratorProperty(itParameter, nameof(KeyValuePair<int, int>.Value), out var valueExpression))
{
return valueExpression;
}

AddError(readerValue, $"{readerValue} is only supported when iterating over dictionary entries");
return UndefinedValue();
}

return Expression.Constant(readerValue);
}

Expand Down
96 changes: 95 additions & 1 deletion tracer/test/Datadog.Trace.Tests/Debugger/DebuggerExpressionLanguageTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
// </copyright>

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
Expand Down Expand Up @@ -44,7 +45,11 @@ public DebuggerExpressionLanguageTests()
HashInt = [1, 2, 3],
Array = ["first", "second"],
CustomArray = [new TestStruct.NestedObject() { NestedString = "Nested" }, new TestStruct.ChildNestedObject() { NestedString = "Nested Child" }],
Dictionary = new Dictionary<string, string> { { "hello", "world" } },
Dictionary = new Dictionary<string, string>
{
{ "hello", "world" },
{ "goodbye", "moon" },
},
IntNumber = 42,
DoubleNumber = 3.14159,
String = "Hello world!",
Expand Down Expand Up @@ -212,6 +217,95 @@ public void ProbeExpressionParser_ValueTypeNull_UsesDefaultValue()
Assert.True(compiled.Errors == null || compiled.Errors.Length == 0);
}

[Theory]
[InlineData("""
{
"any": [
{
"ref": "HashtableLocal"
},
{
"and": [
{
"eq": [
"@key",
"hello"
]
},
{
"eq": [
"@value",
"world"
]
}
]
}
]
}
""")]
[InlineData("""
{
"all": [
{
"ref": "HashtableLocal"
},
{
"ne": [
"@value",
"sun"
]
}
]
}
""")]
[InlineData("""
{
"any": [
{
"filter": [
{
"ref": "HashtableLocal"
},
{
"eq": [
"@key",
"hello"
]
}
]
},
{
"eq": [
"@value",
"world"
]
}
]
}
""")]
public void ProbeExpressionParser_NonGenericDictionaryPredicates_CanUseKeyAndValue(string json)
{
var hashtable = new Hashtable
{
{ "hello", "world" },
{ "goodbye", "moon" },
};

var scopeMembers = CreateScopeMembers();
scopeMembers.AddMember(new ScopeMember("HashtableLocal", typeof(Hashtable), hashtable, ScopeMemberKind.Local));

var compiled = ProbeExpressionParser<bool>.ParseExpression(json, scopeMembers);
var result = compiled.Delegate(
scopeMembers.InvocationTarget,
scopeMembers.Return,
scopeMembers.Duration,
scopeMembers.Exception,
scopeMembers.Members);

Assert.True(result);
Assert.True(compiled.Errors == null || compiled.Errors.Length == 0);
}

private async Task Test(string expressionTestFilePath)
{
// Arrange
Expand Down
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