Introduce AssociativeMethodInvocation check
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| package tech.picnic.errorprone.bugpatterns; | ||
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| import static com.google.errorprone.BugPattern.LinkType.CUSTOM; | ||
| import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION; | ||
| import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION; | ||
| import static com.google.errorprone.matchers.Matchers.allOf; | ||
| import static com.google.errorprone.matchers.Matchers.not; | ||
| import static com.google.errorprone.matchers.Matchers.staticMethod; | ||
| import static com.google.errorprone.matchers.Matchers.toType; | ||
| import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL; | ||
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| import com.google.auto.service.AutoService; | ||
| import com.google.common.collect.ImmutableSet; | ||
| import com.google.errorprone.BugPattern; | ||
| import com.google.errorprone.VisitorState; | ||
| import com.google.errorprone.bugpatterns.BugChecker; | ||
| import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher; | ||
| import com.google.errorprone.fixes.SuggestedFix; | ||
| import com.google.errorprone.fixes.SuggestedFixes; | ||
| import com.google.errorprone.matchers.Description; | ||
| import com.google.errorprone.matchers.Matcher; | ||
| import com.google.errorprone.matchers.Matchers; | ||
| import com.google.errorprone.refaster.Refaster; | ||
| import com.google.errorprone.suppliers.Supplier; | ||
| import com.google.errorprone.suppliers.Suppliers; | ||
| import com.google.errorprone.util.ASTHelpers; | ||
| import com.sun.source.tree.ExpressionTree; | ||
| import com.sun.source.tree.MethodInvocationTree; | ||
| import com.sun.tools.javac.code.Type; | ||
| import tech.picnic.errorprone.bugpatterns.util.SourceCode; | ||
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| /** | ||
| * A {@link BugChecker} that flags unnecessarily nested usage of methods that implement an | ||
| * associative operation. | ||
| * | ||
| * <p>The arguments to such methods can be flattened without affecting semantics, while making the | ||
| * code more readable. | ||
| */ | ||
| @AutoService(BugChecker.class) | ||
| @BugPattern( | ||
| summary = | ||
| "These methods implement an associative operation, so the list of operands can be flattened", | ||
| link = BUG_PATTERNS_BASE_URL + "AssociativeMethodInvocation", | ||
| linkType = CUSTOM, | ||
| severity = SUGGESTION, | ||
| tags = SIMPLIFICATION) | ||
| public final class AssociativeMethodInvocation extends BugChecker | ||
| implements MethodInvocationTreeMatcher { | ||
| private static final long serialVersionUID = 1L; | ||
| private static final Supplier<Type> ITERABLE = Suppliers.typeFromClass(Iterable.class); | ||
| private static final ImmutableSet<Matcher<ExpressionTree>> ASSOCIATIVE_OPERATIONS = | ||
| ImmutableSet.of( | ||
| allOf( | ||
| staticMethod().onClass(Suppliers.typeFromClass(Matchers.class)).named("allOf"), | ||
| toType(MethodInvocationTree.class, not(hasArgumentOfType(ITERABLE)))), | ||
| allOf( | ||
| staticMethod().onClass(Suppliers.typeFromClass(Matchers.class)).named("anyOf"), | ||
| toType(MethodInvocationTree.class, not(hasArgumentOfType(ITERABLE)))), | ||
| staticMethod().onClass(Suppliers.typeFromClass(Refaster.class)).named("anyOf")); | ||
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| /** Instantiates a new {@link AssociativeMethodInvocation} instance. */ | ||
| public AssociativeMethodInvocation() {} | ||
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| @Override | ||
| public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) { | ||
| if (tree.getArguments().isEmpty()) { | ||
| /* Absent any arguments, there is nothing to simplify. */ | ||
| return Description.NO_MATCH; | ||
| } | ||
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| for (Matcher<ExpressionTree> matcher : ASSOCIATIVE_OPERATIONS) { | ||
|
There was a problem hiding this comment. Should we start with the following if statement for fast return (tests still pass)? There was a problem hiding this comment. Pitest will flag it, but I agree 👍 |
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| if (matcher.matches(tree, state)) { | ||
| SuggestedFix.Builder fix = SuggestedFix.builder(); | ||
| for (ExpressionTree arg : tree.getArguments()) { | ||
| if (matcher.matches(arg, state)) { | ||
| MethodInvocationTree invocation = (MethodInvocationTree) arg; | ||
| fix.merge( | ||
| invocation.getArguments().isEmpty() | ||
| ? SuggestedFixes.removeElement(arg, tree.getArguments(), state) | ||
| : SourceCode.unwrapMethodInvocation(invocation, state)); | ||
| } | ||
| } | ||
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| return fix.isEmpty() ? Description.NO_MATCH : describeMatch(tree, fix.build()); | ||
| } | ||
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| } | ||
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| return Description.NO_MATCH; | ||
| } | ||
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| private static Matcher<MethodInvocationTree> hasArgumentOfType(Supplier<Type> type) { | ||
| return (tree, state) -> | ||
| tree.getArguments().stream() | ||
| .anyMatch(arg -> ASTHelpers.isSubtype(ASTHelpers.getType(arg), type.get(state), state)); | ||
| } | ||
| } | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,110 @@ | ||
| package tech.picnic.errorprone.bugpatterns; | ||
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| import com.google.errorprone.BugCheckerRefactoringTestHelper; | ||
| import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode; | ||
| import com.google.errorprone.CompilationTestHelper; | ||
| import org.junit.jupiter.api.Test; | ||
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| final class AssociativeMethodInvocationTest { | ||
| @Test | ||
| void identification() { | ||
| CompilationTestHelper.newInstance(AssociativeMethodInvocation.class, getClass()) | ||
| .addSourceLines( | ||
| "A.java", | ||
| "import com.google.common.collect.ImmutableList;", | ||
| "import com.google.errorprone.matchers.Matchers;", | ||
| "import com.google.errorprone.refaster.Refaster;", | ||
| "", | ||
| "class A {", | ||
| " void m() {", | ||
| " Matchers.allOf();", | ||
| " Matchers.anyOf();", | ||
| " Refaster.anyOf();", | ||
| "", | ||
| " Matchers.allOf((t, s) -> true);", | ||
| " Matchers.anyOf((t, s) -> true);", | ||
| " Refaster.anyOf(0);", | ||
| "", | ||
| " Matchers.allOf(Matchers.anyOf((t, s) -> true));", | ||
| " Matchers.anyOf(Matchers.allOf((t, s) -> true));", | ||
| " Refaster.anyOf(Matchers.allOf((t, s) -> true));", | ||
| "", | ||
| " // BUG: Diagnostic contains:", | ||
| " Matchers.allOf(Matchers.allOf((t, s) -> true));", | ||
| " // BUG: Diagnostic contains:", | ||
| " Matchers.anyOf(Matchers.anyOf((t, s) -> true));", | ||
| " // BUG: Diagnostic contains:", | ||
| " Refaster.anyOf(Refaster.anyOf(0));", | ||
| "", | ||
| " Matchers.allOf(Matchers.allOf(ImmutableList.of((t, s) -> true)));", | ||
| " Matchers.anyOf(Matchers.anyOf(ImmutableList.of((t, s) -> true)));", | ||
| "", | ||
| " // BUG: Diagnostic contains:", | ||
| " Matchers.allOf(", | ||
| " (t, s) -> true, Matchers.allOf((t, s) -> false, (t, s) -> true), (t, s) -> false);", | ||
| " // BUG: Diagnostic contains:", | ||
| " Matchers.anyOf(", | ||
| " (t, s) -> true, Matchers.anyOf((t, s) -> false, (t, s) -> true), (t, s) -> false);", | ||
| " // BUG: Diagnostic contains:", | ||
| " Refaster.anyOf(0, Refaster.anyOf(1, 2), 3);", | ||
| " }", | ||
| "}") | ||
| .doTest(); | ||
| } | ||
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| @Test | ||
| void replacement() { | ||
| BugCheckerRefactoringTestHelper.newInstance(AssociativeMethodInvocation.class, getClass()) | ||
| .addInputLines( | ||
| "A.java", | ||
| "import com.google.errorprone.matchers.Matchers;", | ||
| "import com.google.errorprone.refaster.Refaster;", | ||
| "", | ||
| "class A {", | ||
| " void m() {", | ||
| " Matchers.allOf(Matchers.allOf());", | ||
| " Matchers.anyOf(Matchers.anyOf());", | ||
| " Refaster.anyOf(Refaster.anyOf());", | ||
| "", | ||
| " Matchers.allOf(Matchers.allOf((t, s) -> true));", | ||
| " Matchers.anyOf(Matchers.anyOf((t, s) -> true));", | ||
| " Refaster.anyOf(Refaster.anyOf(0));", | ||
| "", | ||
| " Matchers.allOf(", | ||
| " Matchers.anyOf(),", | ||
| " Matchers.allOf((t, s) -> false, (t, s) -> true),", | ||
| " Matchers.allOf(),", | ||
| " Matchers.anyOf((t, s) -> false));", | ||
| " Matchers.anyOf(", | ||
| " Matchers.allOf(),", | ||
| " Matchers.anyOf((t, s) -> false, (t, s) -> true),", | ||
| " Matchers.anyOf(),", | ||
| " Matchers.allOf((t, s) -> false));", | ||
| " Refaster.anyOf(Matchers.allOf(), Refaster.anyOf(1, 2), Matchers.anyOf());", | ||
| " }", | ||
| "}") | ||
| .addOutputLines( | ||
| "A.java", | ||
| "import com.google.errorprone.matchers.Matchers;", | ||
| "import com.google.errorprone.refaster.Refaster;", | ||
| "", | ||
| "class A {", | ||
| " void m() {", | ||
| " Matchers.allOf();", | ||
| " Matchers.anyOf();", | ||
| " Refaster.anyOf();", | ||
| "", | ||
| " Matchers.allOf((t, s) -> true);", | ||
| " Matchers.anyOf((t, s) -> true);", | ||
| " Refaster.anyOf(0);", | ||
| "", | ||
| " Matchers.allOf(", | ||
| " Matchers.anyOf(), (t, s) -> false, (t, s) -> true, Matchers.anyOf((t, s) -> false));", | ||
| " Matchers.anyOf(", | ||
| " Matchers.allOf(), (t, s) -> false, (t, s) -> true, Matchers.allOf((t, s) -> false));", | ||
| " Refaster.anyOf(Matchers.allOf(), 1, 2, Matchers.anyOf());", | ||
| " }", | ||
| "}") | ||
| .doTest(TestMode.TEXT_MATCH); | ||
| } | ||
| } |
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Why is it "to" in this context, that doesn't sound right 🤔.
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I know that both forms are commonly used (with "of" being more prevalent), but IMHO "to" is better here: we're passing arguments to a method, and they aren't "owned" by the method.