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Improve Rule S2223: cleanup and performance #6761

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merged 14 commits into from Feb 22, 2023
Merged

Improve Rule S2223: cleanup and performance #6761

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874001a
Add more UTs to be more explicit about access modifiers
mary-georgiou-sonarsource Feb 16, 2023
438e2dc
replace semantic model operations with AST ones
mary-georgiou-sonarsource Feb 16, 2023
eed9667
Add test with multiple filed declarations in one line
mary-georgiou-sonarsource Feb 16, 2023
73f5639
more UTS
mary-georgiou-sonarsource Feb 16, 2023
016aebf
update ITs
mary-georgiou-sonarsource Feb 16, 2023
9537be3
delete not useful condition and update UTs
mary-georgiou-sonarsource Feb 16, 2023
c906d02
remove check for const as if there is static keyword then const will …
mary-georgiou-sonarsource Feb 17, 2023
47f6635
if no access modifier exist the field is private
mary-georgiou-sonarsource Feb 17, 2023
f6cf3ad
Revert "update ITs"
mary-georgiou-sonarsource Feb 17, 2023
1f6a2c1
cover also case of private protected modifier
mary-georgiou-sonarsource Feb 21, 2023
0b61972
add more UTs
mary-georgiou-sonarsource Feb 21, 2023
1ad2631
exclude volatile fields from the raising issues
mary-georgiou-sonarsource Feb 22, 2023
53bab05
update rsepc for rule S2223
mary-georgiou-sonarsource Feb 22, 2023
1947aba
apply comments
mary-georgiou-sonarsource Feb 22, 2023
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25 changes: 15 additions & 10 deletions analyzers/src/SonarAnalyzer.CSharp/Rules/StaticFieldVisible.cs
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Expand Up @@ -34,22 +34,27 @@ public sealed class StaticFieldVisible : SonarDiagnosticAnalyzer
context.RegisterNodeAction(
c =>
{
var fieldDeclaration = (FieldDeclarationSyntax)c.Node;
foreach (var diagnostic in GetDiagnostics(fieldDeclaration.Declaration, c.SemanticModel))
foreach (var diagnostic in GetDiagnostics((FieldDeclarationSyntax)c.Node, c.SemanticModel))
{
c.ReportIssue(diagnostic);
}
},
SyntaxKind.FieldDeclaration);

private static IEnumerable<Diagnostic> GetDiagnostics(VariableDeclarationSyntax declaration, SemanticModel semanticModel) =>
declaration.Variables
.Where(x => FieldIsRelevant(semanticModel.GetDeclaredSymbol(x) as IFieldSymbol))
.Select(x => Diagnostic.Create(Rule, x.Identifier.GetLocation(), x.Identifier.ValueText));
private static IEnumerable<Diagnostic> GetDiagnostics(FieldDeclarationSyntax declaration, SemanticModel semanticModel) =>
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FieldIsRelevant(declaration)
? declaration.Declaration.Variables
.Where(x => !FieldIsThreadSafe(semanticModel.GetDeclaredSymbol(x) as IFieldSymbol))
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.Select(x => Diagnostic.Create(Rule, x.Identifier.GetLocation(), x.Identifier.ValueText))
: Enumerable.Empty<Diagnostic>();

private static bool FieldIsRelevant(IFieldSymbol fieldSymbol) =>
fieldSymbol is {IsStatic: true, IsConst: false, IsReadOnly: false}
&& fieldSymbol.DeclaredAccessibility != Accessibility.Private
&& !fieldSymbol.GetAttributes().Any(x => x.AttributeClass.Is(KnownType.System_ThreadStaticAttribute));
private static bool FieldIsRelevant(FieldDeclarationSyntax node) =>
node.Modifiers.Count > 1
&& node.Modifiers.Any(SyntaxKind.StaticKeyword)
&& (!node.Modifiers.Any(SyntaxKind.PrivateKeyword) || (node.Modifiers.Any(SyntaxKind.PrivateKeyword) && node.Modifiers.Any(SyntaxKind.ProtectedKeyword)))
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&& !node.Modifiers.Any(SyntaxKind.ReadOnlyKeyword);
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A volatile field should also be irrelevant as volatile indicates some advanced multi-threading voodoo is going on here.

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maybe good to exclude - per MSDN docs

The volatile keyword indicates that a field might be modified by multiple threads that are executing at the same time.

On a multiprocessor system, a volatile read operation does not guarantee to obtain the latest value written to that memory location by any processor.

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Ok, while I see a public static volatile non-readonly field as dangerous as a public static non-volatile non-readonly one, and it seems that there are almost always ways to have the field private (at least for the typical scenarios of sentinel loopers or counters), let's assume that the person using it has a sound multi-threading model and a solid understanding of it.

So I am OK with disabling the check when volatile is encountered.

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@martin-strecker-sonarsource to resolve this one

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@martin-strecker-sonarsource and I had an offiline convertation on the matter and agreed to the current solution regarding volatile modifier.


private static bool FieldIsThreadSafe(IFieldSymbol fieldSymbol) =>
fieldSymbol.GetAttributes().Any(x => x.AttributeClass.Is(KnownType.System_ThreadStaticAttribute));
}
}
3 changes: 3 additions & 0 deletions analyzers/tests/SonarAnalyzer.UnitTest/TestCases/StaticFieldVisible.CSharp9.cs
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Expand Up @@ -6,6 +6,9 @@ public record StaticFieldVisible
// ^^
public const double Pi2 = 3.14;
public double Pi3 = 3.14;
private protected static double Pi4 = 3.14; // Noncompliant
protected private static double Pi15 = 3.14; // Noncompliant

public static Shape Empty = Shape.Empty; // Noncompliant {{Change the visibility of 'Empty' or make it 'const' or 'readonly'.}}

[ThreadStatic]
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20 changes: 19 additions & 1 deletion analyzers/tests/SonarAnalyzer.UnitTest/TestCases/StaticFieldVisible.cs
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Expand Up @@ -6,11 +6,29 @@ public class StaticFieldVisible
{
public static double Pi = 3.14; // Noncompliant
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// ^^
public static int X = 1, Y, Z = 100;
// ^
// ^@-1
// ^@-2
public const double Pi2 = 3.14;
public double Pi3 = 3.14;

protected static double Pi4 = 3.14; // Noncompliant
internal static double Pi5 = 3.14; // Noncompliant
internal static double Pi6 = 3.14; // Noncompliant
protected internal static double Pi7 = 3.14; // Noncompliant
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It would be good to align vertically all these // Noncompliant.


private static double Pi8 = 3.14;
private double Pi9 = 3.14;
static double Pi10 = 3.14; // Compliant - if no access modifier exist, the field is private
double Pi11 = 3.14;
public readonly double Pi12 = 3.14;

[ThreadStatic]
public static int value; // Compliant, thread static field values are not shared between threads
public static int Value; // Compliant, thread static field values are not shared between threads

[NonSerialized]
public static int Value2; // Noncompliant
}

public class Shape
Expand Down