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UseConsistentWhitespace - Create option to ignore assignment operator inside hash table #1566

Merged
merged 9 commits into from
Jan 5, 2021
80 changes: 80 additions & 0 deletions Engine/TokenOperations.cs
Original file line number Diff line number Diff line change
Expand Up @@ -232,5 +232,85 @@ private bool OnSameLine(Token token1, Token token2)
{
return token1.Extent.StartLineNumber == token2.Extent.EndLineNumber;
}

/// <summary>
/// Finds the position of a given token in the AST.
/// </summary>
/// <param name="token">The <see cref="Token"/> to search for.</param>
/// <returns>The Ast node directly containing the provided <see cref="Token"/>.</returns>
public Ast GetAstPosition(Token token)
{
FindAstPostitionVisitor findAstVisitor = new FindAstPostitionVisitor(token.Extent.StartScriptPosition);
ast.Visit(findAstVisitor);
return findAstVisitor.AstPosition;
}

}

/// <summary>
/// Provides an efficient way to find the position in the AST corresponding to a given script position.
/// </summary>
public class FindAstPostitionVisitor : AstVisitor2
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{
private IScriptPosition searchPosition;

/// <summary>
/// Contains the position in the AST corresponding to the provided <see cref="IScriptPosition"/> upon completion of the <see cref="Ast.Visit(AstVisitor)"/> method.
/// </summary>
public Ast AstPosition { get; private set; }

/// <summary>
/// Initializes a new instance of the <see cref="FindAstPostitionVisitor"/> class with the postition to search for.
/// </summary>
/// <param name="position">The script position to search for.</param>
public FindAstPostitionVisitor(IScriptPosition position)
{
this.searchPosition = position;
}

/// <summary>
/// Traverses the AST based on offests to find the leaf node which contains the provided <see cref="IScriptPosition"/>.
/// This method implements the entire functionality of this visitor. All <see cref="AstVisitor2"/> methods are overridden to simply invoke this one.
/// </summary>
/// <param name="ast">Current AST node to process.</param>
/// <returns>An <see cref="AstVisitAction"/> indicating whether to visit children of the current node.</returns>
private AstVisitAction Visit(Ast ast)
{
if (ast.Extent.StartOffset > searchPosition.Offset || ast.Extent.EndOffset < searchPosition.Offset)
{
return AstVisitAction.SkipChildren;
}
else
{
AstPosition = ast;
return AstVisitAction.Continue;
}
}

public override AstVisitAction VisitScriptBlock(ScriptBlockAst scriptBlockAst)
{
return Visit(scriptBlockAst);
}

public override AstVisitAction VisitNamedBlock(NamedBlockAst namedBlockAst)
{
return Visit(namedBlockAst);
}

public override AstVisitAction VisitAssignmentStatement(AssignmentStatementAst assignmentStatementAst)
{
return Visit(assignmentStatementAst);
}

public override AstVisitAction VisitCommandExpression(CommandExpressionAst commandExpressionAst)
{
return Visit(commandExpressionAst);
}

public override AstVisitAction VisitHashtable(HashtableAst hashtableAst)
{
return Visit(hashtableAst);
}
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Given its general name, this visitor should probably have overrides for all AST types so that it will reliably work for all position visits. The alternative is to implement this class as a private nested class for the relevant rule.

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Fully intend to implement all overrides. Just didn't want to produce that much code before I knew I was barking up the right tree. It flummoxed me a bit when I first decided to work on this that there is no good way to search a PowerShell AST based on script position without writing 200+ lines of code. That is why I had tried the simpler solution first (that I agree with you was not ideal by a long shot).

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@rjmholt rjmholt Aug 11, 2020

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Well there is another way, which is to use FindAll() instead:

IEnumerable<Ast> astsContainingToken = scriptAst.FindAll(foundAst => ContainsTokenExtent(token, foundAst), /* search through nested ASTs -- I can't remember the correct parameter name */ true);

// Find the containing AST with the smallest extent
Ast smallestContainingAst = astsContainingToken.First();
foreach (Ast containingAst in astsContainingToken)
{
    if (HasSmallerExtent(smallestContainingAst, containingAst))
    {
        smallestContainingAst = containingAst;
    }
}

Naturally you'd need to write the methods I've used there, but they basically contain logic you've already written

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I did try something like that but ran into a problem because apparently Ast's can contain another of exactly the same size so there isn't always a smallest. At that point I figured as many issues as I have run into so far trying to use FindAll(), it would be better just to go the visitor route.


}
}
19 changes: 3 additions & 16 deletions Rules/UseConsistentWhitespace.cs
Original file line number Diff line number Diff line change
Expand Up @@ -536,23 +536,10 @@ private IEnumerable<DiagnosticRecord> FindOperatorViolations(TokenOperations tok
// exclude assignment operator inside of multi-line hash tables if requested
if (IgnoreAssignmentOperatorInsideHashTable && tokenNode.Value.Kind == TokenKind.Equals)
{
var enclosingHashTables = tokenOperations.Ast.FindAll(a => a.Extent.StartOffset <= tokenNode.Value.Extent.StartOffset && a.Extent.EndOffset >= tokenNode.Value.Extent.EndOffset && a is HashtableAst, true);
if (enclosingHashTables.Count() > 0)
Ast containingAst = tokenOperations.GetAstPosition(tokenNode.Value);
if (containingAst is HashtableAst && containingAst.Extent.EndLineNumber != containingAst.Extent.StartLineNumber)
{
Ast innermostEnclosingHashTable = enclosingHashTables.First();
int smallestSizeSoFar = int.MaxValue;
foreach (var hashTable in enclosingHashTables){
int currentHashTableSize = hashTable.Extent.EndOffset - hashTable.Extent.StartOffset;
if (currentHashTableSize < smallestSizeSoFar)
{
innermostEnclosingHashTable = hashTable;
smallestSizeSoFar = currentHashTableSize;
}
}
if (innermostEnclosingHashTable.Extent.StartLineNumber != innermostEnclosingHashTable.Extent.EndLineNumber)
{
continue;
}
continue;
}
}

Expand Down
21 changes: 21 additions & 0 deletions Tests/Engine/TokenOperations.tests.ps1
Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License.

Describe "TokenOperations" {
It "Should return correct AST position for assignment operator in hash table" {
$scriptText = @'
$h = @{
a = 72
b = @{ z = "hi" }
}
'@
$tokens = $null
$parseErrors = $null
$scriptAst = [System.Management.Automation.Language.Parser]::ParseInput($scriptText, [ref] $tokens, [ref] $parseErrors)
$tokenOperations = New-Object Microsoft.Windows.PowerShell.ScriptAnalyzer.TokenOperations -ArgumentList @($tokens, $scriptAst)
$operatorToken = $tokens | Where-Object { $_.Extent.StartOffset -eq 32 }
$hashTableAst = $tokenOperations.GetAstPosition($operatorToken)
$hashTableAst | Should -BeOfType [System.Management.Automation.Language.HashTableAst]
$hashTableAst.Extent.Text | Should -Be '@{ z = "hi" }'
}
}