Fixing Java field access #1862

oxisto · 2024-11-21T10:09:20Z

This PR consists of a major overhaul of Java reference and member expression parsing. It removes a LOT of old weird legacy code that was full of weird things.

It also introduces a new Java-specific pass, that takes care of deciding when a member access is actually static or not. This might be something that we could decide to adapt for other/all languages (maybe also tied to the discussion in #1863).

It also contains some adjustments to the import system, more specifically when the importedSymbols field is populated. This might have implications for other languages and if wanted I can extract this into a separate PR.

oxisto · 2024-11-21T14:13:13Z

Blocked by #1586

codecov · 2024-11-21T15:10:17Z

Codecov Report

Attention: Patch coverage is 88.33333% with 7 lines in your changes missing coverage. Please review.

Project coverage is 77.07%. Comparing base (e39f15d) to head (592b8ce).

Files with missing lines	Patch %	Lines
...in/de/fraunhofer/aisec/cpg/passes/JavaExtraPass.kt	68.75%	0 Missing and 5 partials ⚠️
...n/de/fraunhofer/aisec/cpg/passes/ImportResolver.kt	85.71%	0 Missing and 2 partials ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
...n/de/fraunhofer/aisec/cpg/passes/SymbolResolver.kt	`87.65% <100.00%> (-0.31%)`	⬇️
...lin/de/fraunhofer/aisec/cpg/passes/TypeResolver.kt	`95.83% <100.00%> (+0.18%)`	⬆️
...s/kotlin/de/fraunhofer/aisec/cpg/test/TestUtils.kt	`71.27% <ø> (ø)`
...ofer/aisec/cpg/frontends/java/ExpressionHandler.kt	`78.09% <100.00%> (+4.87%)`	⬆️
...r/aisec/cpg/frontends/java/JavaLanguageFrontend.kt	`70.46% <100.00%> (-4.22%)`	⬇️
...n/de/fraunhofer/aisec/cpg/passes/ImportResolver.kt	`89.65% <85.71%> (-0.46%)`	⬇️
...in/de/fraunhofer/aisec/cpg/passes/JavaExtraPass.kt	`68.75% <68.75%> (ø)`

... and 3 files with indirect coverage changes

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KuechA

I fail to understand most of the changes since the old code is hard to understand and the new code requires in-depth knowledge and understanding of the java parser and frontend which I do not have. However, I have some nits which should already be resolved and may support subsequent more detailed reviews.

KuechA · 2024-12-02T09:45:25Z

cpg-core/src/main/kotlin/de/fraunhofer/aisec/cpg/passes/SymbolResolver.kt

@@ -209,7 +209,7 @@ open class SymbolResolver(ctx: TranslationContext) : ComponentPass(ctx) {
        // Preparation for a future without legacy call resolving. Taking the first candidate is not
        // ideal since we are running into an issue with function pointers here (see workaround
        // below).
-        var wouldResolveTo = ref.candidates.singleOrNull()
+        var wouldResolveTo = ref.candidates.firstOrNull()


This change does no longer account for ambiguities. The old code with singleOrNull() prefers not to resolve anything if it's not sure about the candidate. I think this was also intended, wasn't it?

It was semi-intended. I am ok with the old behavior, but we should at least

have a warning if we do not resolve it

forward the decision to the Language. In Java it is possible to have an ambiguity here if you statically import a field and a function and both can have the same name and end up in candidates. I need to deal with that here

KuechA · 2024-12-02T09:49:35Z

cpg-language-java/src/test/kotlin/de/fraunhofer/aisec/cpg/enhancements/calls/SuperCallTest.kt

        val fieldRef = findByUniquePredicate(refs) { "field" == it.code }
        val getSuperField = findByUniqueName(methods, "getSuperField")
        refs = getSuperField.allChildren<MemberExpression>()
        val superFieldRef = findByUniquePredicate(refs) { "super.field" == it.code }
-        assertTrue(fieldRef.base is Reference)
-        assertRefersTo(fieldRef.base, getField.receiver)
+        // See https://github.com/Fraunhofer-AISEC/cpg/issues/1863.


I don't see how this relates to the case of java.

KuechA · 2024-12-02T09:50:36Z

cpg-language-java/src/test/kotlin/de/fraunhofer/aisec/cpg/enhancements/calls/SuperCallTest.kt

+        // See https://github.com/Fraunhofer-AISEC/cpg/issues/1863.
+        // We only have a regular call expression here, if we do not resolve anything else in the
+        // frontend
+        /*assertTrue(fieldRef.base is Reference)


commented out code. -> Remove or fix. What do we expect?

KuechA · 2024-12-02T09:54:04Z

cpg-language-java/src/main/kotlin/de/fraunhofer/aisec/cpg/frontends/java/ExpressionHandler.kt

@@ -889,3 +658,21 @@ class ExpressionHandler(lang: JavaLanguageFrontend) :
        }
    }
 }
+
+fun ResolvedFieldDeclaration.toFieldAccessExpr(expr: NameExpr): FieldAccessExpr {


Documentation missing

KuechA · 2024-12-02T10:00:03Z

cpg-language-java/src/main/kotlin/de/fraunhofer/aisec/cpg/frontends/java/ExpressionHandler.kt

-        //    }
-        val name = this.parseName(nameExpr.nameAsString)
-        return try {
+        // Try to resolve it. We will remove this in a future where we do not really in the


Is the TODO of this method resolved? If so, please delete it.

Also, please document the method according to the new standards: #1683 (comment)

This sentence is broken

KuechA · 2024-12-02T10:03:41Z

cpg-language-java/src/main/kotlin/de/fraunhofer/aisec/cpg/frontends/java/ExpressionHandler.kt

-                    ?: newProblemExpression("Could not parse base")
-        }
-        var fieldType: Type?
+


Please document the method according to the new standards: #1683 (comment)

KuechA · 2024-12-02T10:07:00Z

cpg-language-java/src/main/kotlin/de/fraunhofer/aisec/cpg/passes/JavaExtraPass.kt

+
+@DependsOn(TypeResolver::class)
+@ExecuteBefore(SymbolResolver::class)
+class JavaExtraPass(ctx: TranslationContext) : TranslationUnitPass(ctx) {


Documentation missing for this whole file

oxisto · 2024-12-18T08:56:02Z

I fail to understand most of the changes since the old code is hard to understand and the new code requires in-depth knowledge and understanding of the java parser and frontend which I do not have. However, I have some nits which should already be resolved and may support subsequent more detailed reviews.

Agreed. I will extract the remaining changes that are not Java-specific to extra PRs

oxisto mentioned this pull request Nov 21, 2024

Removing legacy resolveReference function #1861

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oxisto added the blocked Blocked by an external factor label Nov 21, 2024

oxisto force-pushed the java-fix-static branch from c781e33 to faaa036 Compare November 21, 2024 14:34

oxisto force-pushed the java-fix-static branch from 4c7279c to 952f56c Compare November 28, 2024 14:00

oxisto removed the blocked Blocked by an external factor label Nov 28, 2024

oxisto force-pushed the java-fix-static branch from 952f56c to 5f75416 Compare November 28, 2024 14:05

oxisto marked this pull request as ready for review November 28, 2024 14:05

oxisto requested review from konradweiss and KuechA as code owners November 28, 2024 14:05

oxisto added the java Related to Java language parsing label Nov 28, 2024

oxisto force-pushed the java-fix-static branch from 5f75416 to c7f72a6 Compare November 28, 2024 20:56

KuechA reviewed Dec 2, 2024

View reviewed changes

Fixing Java field access

592b8ce

oxisto force-pushed the java-fix-static branch from c7f72a6 to 592b8ce Compare December 18, 2024 08:49

oxisto mentioned this pull request Dec 18, 2024

Providing an API to update the imported symbols for an ImportDeclaration #1908

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Fixing Java field access #1862

Fixing Java field access #1862

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oxisto commented Dec 18, 2024

Fixing Java field access #1862

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Fixing Java field access #1862

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oxisto commented Dec 18, 2024

oxisto commented Nov 21, 2024 •

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codecov bot commented Nov 21, 2024 •

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