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Fix NullReferenceException in AvoidAssignmentToAutomaticVariable rule when assigning a .Net property and only look at the LHS #1008

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Merged
bergmeister merged 6 commits into from
Jun 5, 2018
Merged

Fix NullReferenceException in AvoidAssignmentToAutomaticVariable rule when assigning a .Net property and only look at the LHS #1008

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3701e65
Fix NullReferenceException in AvoidAssignmentToAutomaticVariable rule…
bergmeister Jun 2, 2018
9910fda
when variableExpressionAst is null, then continue loop to reduce nesting
bergmeister Jun 4, 2018
e4d1c72
fix indentation for cleaner diff
bergmeister Jun 4, 2018
8136638
Fix issue #1013 as well by making sure the rule looks only the LHS
bergmeister Jun 4, 2018
f818df7
Fix issue #1012 as well
bergmeister Jun 4, 2018
9fbe4e1
Simplify test that checks that PSSA does not throw to address PR review
bergmeister Jun 5, 2018
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25 changes: 14 additions & 11 deletions Rules/AvoidAssignmentToAutomaticVariable.cs
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Expand Up @@ -47,18 +47,21 @@ public IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string fileName)
foreach (var assignmentStatementAst in assignmentStatementAsts)
{
var variableExpressionAst = assignmentStatementAst.Find(testAst => testAst is VariableExpressionAst, searchNestedScriptBlocks: false) as VariableExpressionAst;
var variableName = variableExpressionAst.VariablePath.UserPath;
if (_readOnlyAutomaticVariables.Contains(variableName, StringComparer.OrdinalIgnoreCase))
if (variableExpressionAst != null)

@bergmeister bergmeister Jun 2, 2018

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only this null check was added, all the code diff below is only the added indentation

@JamesWTruher JamesWTruher Jun 4, 2018

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from a flow perspective, this could also be

if ( variableExpressionAst == null )
   continue

and the indenting is preserved :)

{
yield return new DiagnosticRecord(DiagnosticRecordHelper.FormatError(Strings.AvoidAssignmentToReadOnlyAutomaticVariableError, variableName),
variableExpressionAst.Extent, GetName(), DiagnosticSeverity.Error, fileName);
}

if (_readOnlyAutomaticVariablesIntroducedInVersion6_0.Contains(variableName, StringComparer.OrdinalIgnoreCase))
{
var severity = IsPowerShellVersion6OrGreater() ? DiagnosticSeverity.Error : DiagnosticSeverity.Warning;
yield return new DiagnosticRecord(DiagnosticRecordHelper.FormatError(Strings.AvoidAssignmentToReadOnlyAutomaticVariableIntroducedInPowerShell6_0Error, variableName),
variableExpressionAst.Extent, GetName(), severity, fileName);
var variableName = variableExpressionAst.VariablePath.UserPath;
if (_readOnlyAutomaticVariables.Contains(variableName, StringComparer.OrdinalIgnoreCase))
{
yield return new DiagnosticRecord(DiagnosticRecordHelper.FormatError(Strings.AvoidAssignmentToReadOnlyAutomaticVariableError, variableName),
variableExpressionAst.Extent, GetName(), DiagnosticSeverity.Error, fileName);
}

if (_readOnlyAutomaticVariablesIntroducedInVersion6_0.Contains(variableName, StringComparer.OrdinalIgnoreCase))
{
var severity = IsPowerShellVersion6OrGreater() ? DiagnosticSeverity.Error : DiagnosticSeverity.Warning;
yield return new DiagnosticRecord(DiagnosticRecordHelper.FormatError(Strings.AvoidAssignmentToReadOnlyAutomaticVariableIntroducedInPowerShell6_0Error, variableName),
variableExpressionAst.Extent, GetName(), severity, fileName);
}
}
}

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15 changes: 15 additions & 0 deletions Tests/Rules/AvoidAssignmentToAutomaticVariable.tests.ps1
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Expand Up @@ -63,6 +63,21 @@ Describe "AvoidAssignmentToAutomaticVariables" {
$warnings.Count | Should -Be 0
}

It "Does not throw a NullReferenceException when using assigning a .Net property to a .Net property (Bug in 1.17.0 - issue 1007)" {
$exceptionThrown = $false
try

@JamesWTruher JamesWTruher Jun 4, 2018

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shouldn't this just be:
{ Invoke-ScriptAnalyzer -ScriptDefinition '[foo]::bar = [baz]::quz' -ErrorAction Stop } | Should Not Throw
It will make the log easier to understand if it fails.

@bergmeister bergmeister Jun 4, 2018

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Pester only works with terminating errors. PSSA throws non-terminating errors, see pester/Pester#366

@JamesWTruher JamesWTruher Jun 4, 2018

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i would have thought that -ErrorAction Stop would do the trick (after all, it's in a try/catch, so you're doing the same thing) so somebody is halting the pipeline

{
Invoke-ScriptAnalyzer -ScriptDefinition '[foo]::bar = [baz]::qux' -ErrorAction Stop
}
catch
{
$exceptionThrown = $true
}

$exceptionThrown | Should -Be $false
}


It "Setting Variable <VariableName> throws exception in applicable PowerShell version to verify the variables is read-only" -TestCases $testCases_ReadOnlyVariables {
param ($VariableName, $ExpectedSeverity, $OnlyPresentInCoreClr)

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