test: audit helper-mediated source reads

tools/audit-test-inventory.ps1

@@ -10,7 +10,7 @@
     signals (including same-file helper calls), diagnostic output signals,
     high-confidence constant-truth assertions, syntactic self-comparison
     candidates, wall-clock waits, environment-variable dependencies, and
-    source-text reads.
+    source-text reads, including reads reached through same-file helper calls.
 
     This is a candidate generator, not a semantic proof. In particular, an
     output-only candidate can call a failure-capable helper declared in another
@@ -192,6 +192,39 @@ function Test-DirectOutputSignal {
     return $false
 }
 
+function Test-CSharpPathLiteral {
+    param([Parameter(Mandatory)]$Method)
+
+    foreach ($literal in @($Method.DescendantNodes() | Where-Object {
+                $_.GetType().Name -eq 'LiteralExpressionSyntax'
+            })) {
+        if ($literal.Token.ValueText -match '(?i)\.cs') {
+            return $true
+        }
+    }
+    foreach ($text in @($Method.DescendantNodes() | Where-Object {
+                $_.GetType().Name -eq 'InterpolatedStringTextSyntax'
+            })) {
+        if ($text.TextToken.ValueText -match '(?i)\.cs') {
+            return $true
+        }
+    }
+    return $false
+}
+
+function Test-TextFileRead {
+    param([Parameter(Mandatory)]$Method)
+
+    foreach ($member in @($Method.DescendantNodes() | Where-Object {
+                $_.GetType().Name -eq 'MemberAccessExpressionSyntax'
+            })) {
+        if ($member.Name.Identifier.Text -in @('ReadAllText', 'ReadAllLines')) {
+            return $true
+        }
+    }
+    return $false
+}
+
 function Get-AssertionAuditSites {
     param(
         [Parameter(Mandatory)]$Tree,
@@ -391,6 +424,8 @@ foreach ($relativePath in $trackedFiles) {
     $methodMap = @{}
     $failureMap = @{}
     $outputMap = @{}
+    $textReadMap = @{}
+    $csharpPathMap = @{}
     $gateMap = @{}
     $callMap = @{}
 
@@ -400,6 +435,8 @@ foreach ($relativePath in $trackedFiles) {
         $methodMap[$key] = $method
         $failureMap[$key] = Test-DirectFailureSignal $method
         $outputMap[$key] = Test-DirectOutputSignal $method
+        $textReadMap[$key] = Test-TextFileRead $method
+        $csharpPathMap[$key] = Test-CSharpPathLiteral $method
         $gateMap[$key] = @(Get-EmptyReturnSites $tree $method)
         $callMap[$key] = @($method.DescendantNodes() |
             Where-Object { $_.GetType().Name -eq 'InvocationExpressionSyntax' } |
@@ -425,6 +462,11 @@ foreach ($relativePath in $trackedFiles) {
             $key $methodMap $failureMap $callMap @{}
         $hasOutputSignal = Test-RecursiveSignal `
             $key $methodMap $outputMap $callMap @{}
+        $readsFileText = Test-RecursiveSignal `
+            $key $methodMap $textReadMap $callMap @{}
+        $usesCsharpPath = Test-RecursiveSignal `
+            $key $methodMap $csharpPathMap $callMap @{}
+        $readsSourceText = $readsFileText -and $usesCsharpPath
 
         $emptyReturns = @($gateMap[$key])
         $helperPrerequisiteReturns = @(Get-RecursivePrerequisiteGateSites `
@@ -518,8 +560,9 @@ foreach ($relativePath in $trackedFiles) {
                     @($waitSites | Where-Object {
                             -not $_.IsCancellableInfiniteDelay
                         }).Count -eq 0
-                ReadsSourceText = $bodyText -match '(ReadAllText|ReadAllLines)\s*\(' -and
-                    $bodyText -match '\.cs'
+                ReadsSourceTextDirectly = [bool]($textReadMap[$key] -and
+                    $csharpPathMap[$key])
+                ReadsSourceText = $readsSourceText
             })
     }
 }
@@ -668,6 +711,9 @@ $summary = [ordered]@{
     DirectEnvironmentVariableMethods = @($orderedRecords | Where-Object {
             $_.EnvironmentVariables.Count -gt 0
         }).Count
+    DirectSourceTextReadMethods = @($orderedRecords | Where-Object {
+            $_.ReadsSourceTextDirectly
+        }).Count
     SourceTextReadMethods = @($orderedRecords | Where-Object { $_.ReadsSourceText }).Count
 }