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[DI-EL] Add debug log in case evaluation result is null and it shouldn't be null #7558

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Merged
merged 1 commit into from
Oct 2, 2025
Merged

[DI-EL] Add debug log in case evaluation result is null and it shouldn't be null #7558

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10 changes: 5 additions & 5 deletions tracer/src/Datadog.Trace/Debugger/Expressions/ExpressionEvaluationResult.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,19 +20,19 @@ internal ref struct ExpressionEvaluationResult

internal List<EvaluationError> Errors { get; set; }

internal bool HasError => Errors is { Count: > 0 };
internal readonly bool HasError => Errors is { Count: > 0 };

internal bool IsNull()
internal readonly bool IsNull()
{
return Template == null && Condition == null && Metric == null && Decorations?.Length == 0 && Errors == null;
}

internal struct DecorationResult
{
public string TagName { get; set; }
internal string TagName { get; set; }

public string Value { get; set; }
internal string Value { get; set; }

public EvaluationError[] Errors { get; set; }
internal EvaluationError[] Errors { get; set; }
}
}
12 changes: 6 additions & 6 deletions tracer/src/Datadog.Trace/Debugger/Expressions/ProbeInfo.cs
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Expand Up @@ -41,9 +41,9 @@ internal record struct ProbeInfo(

internal string[] Tags { get; } = Tags;

public TargetSpan? TargetSpan { get; } = TargetSpan;
internal TargetSpan? TargetSpan { get; } = TargetSpan;

public CaptureLimitInfo CaptureLimitInfo { get; } = CaptureLimitInfo;
internal CaptureLimitInfo CaptureLimitInfo { get; } = CaptureLimitInfo;
}

internal readonly record struct CaptureLimitInfo(
Expand All @@ -52,12 +52,12 @@ internal readonly record struct CaptureLimitInfo(
int MaxLength,
int MaxFieldCount)
{
public int MaxReferenceDepth { get; } = MaxReferenceDepth;
internal int MaxReferenceDepth { get; } = MaxReferenceDepth;

public int MaxCollectionSize { get; } = MaxCollectionSize;
internal int MaxCollectionSize { get; } = MaxCollectionSize;

public int MaxLength { get; } = MaxLength;
internal int MaxLength { get; } = MaxLength;

public int MaxFieldCount { get; } = MaxFieldCount;
internal int MaxFieldCount { get; } = MaxFieldCount;
}
}
50 changes: 44 additions & 6 deletions tracer/src/Datadog.Trace/Debugger/Expressions/ProbeProcessor.cs
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Expand Up @@ -2,6 +2,7 @@
// Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
// This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
// </copyright>

#nullable enable

using System;
Expand Down Expand Up @@ -349,6 +350,8 @@ private ExpressionEvaluationResult Evaluate(DebuggerSnapshotCreator snapshotCrea

if (evaluationResult.IsNull())
{
LogEvaluationState(snapshotCreator.MethodScopeMembers);

Log.Error("Evaluation result should not be null. Probe: {ProbeId}", ProbeInfo.ProbeId);
evaluationResult.Errors = new List<EvaluationError> { new() { Message = $"Evaluation result is null. Probe ID: {ProbeInfo.ProbeId}" } };
return evaluationResult;
Expand Down Expand Up @@ -390,15 +393,45 @@ private ExpressionEvaluationResult Evaluate(DebuggerSnapshotCreator snapshotCrea
return evaluationResult;
}

private void SetSpanDecoration(DebuggerSnapshotCreator snapshotCreator, ref bool shouldStopCapture, ExpressionEvaluationResult evaluationResult)
private void LogEvaluationState(MethodScopeMembers methodScopeMembers)
{
if (!TryGetScope(out var scope))
if (_templates == null
&& _condition == null
&& _metric == null
&& _spanDecorations == null)
{
return;
}

// this should never happen, but if it does, we want to log it for further investigation
Log.Error("Evaluation state error: we thought that evaluation result is null but that not true. probably we are using an incorrect version of ProbeExpressionEvaluator");

try
{
if (Log.IsEnabled(LogEventLevel.Debug))
{
Log.Debug("No active scope available, skipping span decoration. Probe: {ProbeId}", ProbeInfo.ProbeId);
var instance = methodScopeMembers.InvocationTarget;
var members = methodScopeMembers.Members?.Select(m => new { Name = m.Name, Type = m.Type?.FullName ?? m.Type?.Name }).ToList();
string? membersAsString = null;
if (members?.Any() == true)
{
membersAsString = string.Join(";", members);
}

Log.Error("Evaluation state error: Target Method: Type = {Type}, Name = {Name}. Method Members: {Members}", instance.Type?.FullName ?? instance.Type?.Name, instance.Name, membersAsString);
}
}
catch
{
// ignored
}
}

private void SetSpanDecoration(DebuggerSnapshotCreator snapshotCreator, ref bool shouldStopCapture, ExpressionEvaluationResult evaluationResult)
{
if (!TryGetScope(out var scope))
{
Log.Debug("No active scope available, skipping span decoration. Probe: {ProbeId}", ProbeInfo.ProbeId);
return;
}

Expand All @@ -411,6 +444,11 @@ private void SetSpanDecoration(DebuggerSnapshotCreator snapshotCreator, ref bool
var probeIdTag = $"{DynamicPrefix}{decoration.TagName}.probe_id";
ISpan? targetSpan = null;

if (ProbeInfo.TargetSpan == null)
{
Log.Error("We can't set the {Tag} tag. Probe ID: {ProbeId}, because target span is null", decoration.TagName, ProbeInfo.ProbeId);
}

switch (ProbeInfo.TargetSpan)
{
case TargetSpan.Root:
Expand All @@ -420,13 +458,13 @@ private void SetSpanDecoration(DebuggerSnapshotCreator snapshotCreator, ref bool
targetSpan = scope.Span;
break;
default:
Log.Error("Invalid target span. Probe: {ProbeId}", ProbeInfo.ProbeId);
Log.Error("We can't set the {Tag} tag. Probe ID: {ProbeId}, because target span {Span} is invalid", decoration.TagName, ProbeInfo.ProbeId, ProbeInfo.TargetSpan);
break;
}

if (targetSpan == null)
{
Log.Warning("No root span or active span is available, so we can't set the {Tag} tag. Probe ID: {ProbeId}", decoration.TagName, ProbeInfo.ProbeId);
Log.Warning("We can't set the {Tag} tag. Probe ID: {ProbeId}, because the chosen span {Span} is not available", decoration.TagName, ProbeInfo.ProbeId, ProbeInfo.TargetSpan);
continue;
}

Expand All @@ -444,7 +482,7 @@ private void SetSpanDecoration(DebuggerSnapshotCreator snapshotCreator, ref bool
attachedTags = true;
if (Log.IsEnabled(LogEventLevel.Debug))
{
Log.Debug("Successfully attached tag {Tag} to span {Span}. ProbID={ProbeId}", decoration.TagName, targetSpan.SpanId, ProbeInfo.ProbeId);
Log.Debug("Successfully attached tag {Tag} to span {Span}. ProbID: {ProbeId}", decoration.TagName, targetSpan.SpanId, ProbeInfo.ProbeId);
}
}

Expand Down
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