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Fix S2583/2589 FP: Return inside lock, using and finally causes FP af…
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…ter the block (#8761)
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@pavel-mikula-sonarsource
pavel-mikula-sonarsource committed Feb 16, 2024
1 parent 4644b28 commit afd7543
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Showing 6 changed files with 626 additions and 496 deletions.
23 changes: 21 additions & 2 deletions analyzers/src/SonarAnalyzer.Common/SymbolicExecution/Roslyn/ExplodedNode.cs
View file
Expand Up @@ -58,18 +58,37 @@ public int AddVisit()
}

public override int GetHashCode() =>
HashCode.Combine(programPointHash, State);
HashCode.Combine(programPointHash, State, FinallyPoint?.BlockIndex);

public override bool Equals(object obj) =>
Equals(obj as ExplodedNode);

public bool Equals(ExplodedNode other) =>
other is not null
&& other.programPointHash == programPointHash
&& other.State.Equals(State);
&& other.State.Equals(State)
&& HasSameFinallyPointChain(other.FinallyPoint);

public override string ToString() =>
Operation.Instance is { } operation
? $"Block #{Block.Ordinal}, Operation #{index}, {operation.Serialize()}{Environment.NewLine}{State}"
: $"Block #{Block.Ordinal}, Branching{Environment.NewLine}{State}";

private bool HasSameFinallyPointChain(FinallyPoint other)
{
var current = FinallyPoint;
while (current is not null && other is not null)
{
if (current.BlockIndex == other.BlockIndex && current.BranchDestination == other.BranchDestination)
{
current = current.Previous;
other = other.Previous;
}
else
{
return false;
}
}
return current is null && other is null;
}
}
1 change: 1 addition & 0 deletions analyzers/src/SonarAnalyzer.Common/SymbolicExecution/Roslyn/FinallyPoint.cs
View file
Expand Up @@ -29,6 +29,7 @@ public sealed class FinallyPoint

public bool IsFinallyBlock => finallyIndex < branch.FinallyRegions.Length;
public int BlockIndex => IsFinallyBlock ? branch.FinallyRegions[finallyIndex].FirstBlockOrdinal : branch.Destination.Ordinal;
public int BranchDestination => branch.Destination.Ordinal;
public FinallyPoint Previous { get; }

public FinallyPoint(FinallyPoint previous, ControlFlowBranch branch, int finallyIndex = 0)
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125 changes: 105 additions & 20 deletions analyzers/tests/SonarAnalyzer.Test/SymbolicExecution/Roslyn/ExplodedNodeTest.cs
View file
Expand Up @@ -18,9 +18,9 @@
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

using System.Xml.Linq;
using SonarAnalyzer.Extensions;
using SonarAnalyzer.SymbolicExecution.Roslyn;
using SonarAnalyzer.Test.Helpers;

namespace SonarAnalyzer.Test.SymbolicExecution.Roslyn;

Expand Down Expand Up @@ -113,19 +113,101 @@ public void Equals_ReturnsTrueForEquivalent()
basic.Equals((ExplodedNode)null).Should().BeFalse(); // Explicit cast to ensure correct overload
}

[TestMethod]
public void Equals_FinallyPoints_Single()
{
var cfg = TestHelper.CompileCfgBodyCS("""
try
{
if (condition)
{
return; // Branch goes to exit 1->5, skipping AfterFinally
}
if (condition)
{
return; // Branch goes to exit 2->5, skipping AfterFinally
}
// Branch goes AfterFinally 2->4
}
finally
{
System.Console.WriteLine("Finally");
}
System.Console.WriteLine("AfterFinally");
""", "bool condition");
var block = cfg.Blocks[0];
var from1to5 = cfg.Blocks[1].Successors.Single(x => x.Destination.Ordinal == 5);
var from2to5 = cfg.Blocks[2].Successors.Single(x => x.Destination.Ordinal == 5);
var from2to4 = cfg.Blocks[2].Successors.Single(x => x.Destination.Ordinal == 4);
var node = new ExplodedNode(block, ProgramState.Empty, new FinallyPoint(null, from1to5));
var noFinally = new ExplodedNode(block, ProgramState.Empty, null);

node.Equals(new ExplodedNode(block, ProgramState.Empty, new FinallyPoint(null, from2to5))).Should().BeTrue("We consider only same destination block");
node.Equals(new ExplodedNode(block, ProgramState.Empty, new FinallyPoint(null, from2to4))).Should().BeFalse("It has different destination block");
node.Equals(new ExplodedNode(block, ProgramState.Empty, new FinallyPoint(null, from1to5, 1))).Should().BeFalse("It has different BlockIndex");
node.Equals(noFinally).Should().BeFalse();
noFinally.Equals(node).Should().BeFalse();
}

[TestMethod]
public void Equals_FinallyPoints_WithPrevious()
{
var cfg = TestHelper.CompileCfgBodyCS("""
try
{
if (condition)
{
return; // Branch goes to exit, skipping AfterFinally
}
if (condition)
{
return; // Branch goes to exit, skipping AfterFinally
}
// Branch goes AfterFinally
}
finally
{
System.Console.WriteLine("Finally");
}
System.Console.WriteLine("AfterFinally");
""", "bool condition");
var block = cfg.Blocks[0];
var outerSame = cfg.Blocks[0].Successors.Single();
var from1to5 = cfg.Blocks[1].Successors.Single(x => x.Destination.Ordinal == 5);
var from2to5 = cfg.Blocks[2].Successors.Single(x => x.Destination.Ordinal == 5);
var from2to4 = cfg.Blocks[2].Successors.Single(x => x.Destination.Ordinal == 4);
var node = new ExplodedNode(block, ProgramState.Empty, new FinallyPoint(new FinallyPoint(null, from1to5), outerSame));
var noFinally = new ExplodedNode(block, ProgramState.Empty, Wrap(null));

node.Equals(new ExplodedNode(block, ProgramState.Empty, Wrap(new FinallyPoint(null, from2to5)))).Should().BeTrue("We consider only same destination block");
node.Equals(new ExplodedNode(block, ProgramState.Empty, Wrap(new FinallyPoint(null, from2to4)))).Should().BeFalse("It has different destination block");
node.Equals(new ExplodedNode(block, ProgramState.Empty, Wrap(new FinallyPoint(null, from1to5, 1)))).Should().BeFalse("It has different BlockIndex");
node.Equals(noFinally).Should().BeFalse();
noFinally.Equals(node).Should().BeFalse();

FinallyPoint Wrap(FinallyPoint inner) =>
new(inner, outerSame);
}

[TestMethod]
public void GetHashCode_ReturnsSameForEquivalent()
{
var block = TestHelper.CompileCfgBodyCS("var a = true;").Blocks[1];
var basic = new ExplodedNode(block, ProgramState.Empty, null);
var same = new ExplodedNode(block, ProgramState.Empty, null);
var cfg = TestHelper.CompileCfgBodyCS("var a = true;");
var block = cfg.Blocks[1];
var finallyPoint = new FinallyPoint(null, block.Successors.Single());
var basic = new ExplodedNode(block, ProgramState.Empty, finallyPoint);
var same = new ExplodedNode(block, ProgramState.Empty, finallyPoint);
var differentLocation = basic.CreateNext(ProgramState.Empty);
var differentState = new ExplodedNode(block, ProgramState.Empty.SetOperationValue(block.Operations[0], SymbolicValue.Empty), null);
var differentState = new ExplodedNode(block, ProgramState.Empty.SetOperationValue(block.Operations[0], SymbolicValue.Empty), finallyPoint);
var differentNoFinallyPoint = new ExplodedNode(block, ProgramState.Empty, null);
var differentFinallyPointBlockIndex = new ExplodedNode(block, ProgramState.Empty, new(null, cfg.Blocks[0].Successors.Single()));

basic.GetHashCode().Should().Be(basic.GetHashCode(), "value should be deterministic");
basic.GetHashCode().Should().Be(same.GetHashCode());
basic.GetHashCode().Should().NotBe(differentLocation.GetHashCode());
basic.GetHashCode().Should().NotBe(differentState.GetHashCode());
basic.GetHashCode().Should().NotBe(differentNoFinallyPoint.GetHashCode());
basic.GetHashCode().Should().NotBe(differentFinallyPointBlockIndex.GetHashCode());
}

[TestMethod]
Expand All @@ -134,21 +216,24 @@ public void ToString_SerializeOperationAndState()
var cfg = TestHelper.CompileCfgBodyCS("var a = true;");
var state = ProgramState.Empty.SetSymbolValue(cfg.Blocks[1].Operations[0].ChildOperations.First().TrackedSymbol(ProgramState.Empty), SymbolicValue.Empty);

new ExplodedNode(cfg.Blocks[0], ProgramState.Empty, null).ToString().Should().BeIgnoringLineEndings(
@"Block #0, Branching
Empty
");

new ExplodedNode(cfg.Blocks[1], state, null).ToString().Should().BeIgnoringLineEndings(
@"Block #1, Operation #0, LocalReferenceOperation: a = true
Symbols:
a: No constraints
");
new ExplodedNode(cfg.ExitBlock, state, null).ToString().Should().BeIgnoringLineEndings(
@"Block #2, Branching
Symbols:
a: No constraints
");
new ExplodedNode(cfg.Blocks[0], ProgramState.Empty, null).ToString().Should().BeIgnoringLineEndings("""
Block #0, Branching
Empty

""");

new ExplodedNode(cfg.Blocks[1], state, null).ToString().Should().BeIgnoringLineEndings("""
Block #1, Operation #0, LocalReferenceOperation: a = true
Symbols:
a: No constraints

""");
new ExplodedNode(cfg.ExitBlock, state, null).ToString().Should().BeIgnoringLineEndings("""
Block #2, Branching
Symbols:
a: No constraints

""");
}

[TestMethod]
Expand Down
33 changes: 17 additions & 16 deletions analyzers/tests/SonarAnalyzer.Test/SymbolicExecution/Roslyn/FinallyPointTest.cs
View file
Expand Up @@ -36,22 +36,23 @@ public void Constructor_Null_Throws()
[TestMethod]
public void CreateNext_ReturnsAllFinally_AndThenDestination()
{
const string code = @"
try
{
try
{
true.ToString();
}
finally
{
true.ToString();
}
}
finally
{
true.ToString();
}";
const string code = """
try
{
try
{
true.ToString();
}
finally
{
true.ToString();
}
}
finally
{
true.ToString();
}
""";
var cfg = TestHelper.CompileCfgBodyCS(code);
var sut = new FinallyPoint(null, cfg.Blocks[1].FallThroughSuccessor);
sut.BlockIndex.Should().Be(2); // Inner finally
Expand Down

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