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Propagate nullness facts for CastToNonNullMethod #1630

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fcfb69f
Propagate nullness facts for CastToNonNullMethod
Shankar-v27 Jul 16, 2026
d77217b
Avoid unnecessary string allocation for CastToNonNullMethod
Shankar-v27 Jul 16, 2026
6070232
Add CastToNonNullMethodFailsOnNull configuration option
Shankar-v27 Jul 20, 2026
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8 changes: 8 additions & 0 deletions nullaway/src/main/java/com/uber/nullaway/Config.java
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Original file line number Diff line number Diff line change
Expand Up @@ -240,6 +240,14 @@ public interface Config {
*/
@Nullable String getCastToNonNullMethod();

/**
* Checks whether the <code>castToNonNull()</code> method should be treated as failing on null.
*
* @return true if <code>castToNonNull()</code> methods are guaranteed to throw when passed null,
* false otherwise
*/
boolean castToNonNullMethodFailsOnNull();

/**
* Gets the suppression name aliases.
*
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5 changes: 5 additions & 0 deletions nullaway/src/main/java/com/uber/nullaway/DummyOptionsConfig.java
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Expand Up @@ -179,6 +179,11 @@ public Set<String> getOptionalClassPaths() {
throw new IllegalStateException(ERROR_MESSAGE);
}

@Override
public boolean castToNonNullMethodFailsOnNull() {
throw new IllegalStateException(ERROR_MESSAGE);
}

@Override
public Set<String> getSuppressionNameAliases() {
throw new IllegalStateException(ERROR_MESSAGE);
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9 changes: 9 additions & 0 deletions nullaway/src/main/java/com/uber/nullaway/ErrorProneCLIFlagsConfig.java
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Expand Up @@ -66,6 +66,8 @@ final class ErrorProneCLIFlagsConfig implements Config {
static final String FL_NULLABLE_ANNOT = EP_FL_NAMESPACE + ":CustomNullableAnnotations";
static final String FL_NONNULL_ANNOT = EP_FL_NAMESPACE + ":CustomNonnullAnnotations";
static final String FL_CTNN_METHOD = EP_FL_NAMESPACE + ":CastToNonNullMethod";
static final String FL_CTNN_METHOD_FAILS_ON_NULL =
EP_FL_NAMESPACE + ":CastToNonNullMethodFailsOnNull";
static final String FL_EXTERNAL_INIT_ANNOT = EP_FL_NAMESPACE + ":ExternalInitAnnotations";
static final String FL_CONTRACT_ANNOT = EP_FL_NAMESPACE + ":CustomContractAnnotations";
static final String FL_UNANNOTATED_CLASSES = EP_FL_NAMESPACE + ":UnannotatedClasses";
Expand Down Expand Up @@ -243,6 +245,7 @@ final class ErrorProneCLIFlagsConfig implements Config {
private final ImmutableSet<String> externalInitAnnotations;
private final ImmutableSet<String> contractAnnotations;
private final @Nullable String castToNonNullMethod;
private final boolean castToNonNullMethodFailsOnNull;
private final String autofixSuppressionComment;
private final ImmutableSet<String> suppressionNameAliases;
private final ImmutableSet<String> skippedLibraryModels;
Expand Down Expand Up @@ -312,6 +315,7 @@ final class ErrorProneCLIFlagsConfig implements Config {
getPackagePattern(
getFlagStringSet(flags, FL_EXCLUDED_FIELD_ANNOT, DEFAULT_EXCLUDED_FIELD_ANNOT));
castToNonNullMethod = flags.get(FL_CTNN_METHOD).orElse(null);
castToNonNullMethodFailsOnNull = flags.getBoolean(FL_CTNN_METHOD_FAILS_ON_NULL).orElse(false);
legacyAnnotationLocation = flags.getBoolean(FL_LEGACY_ANNOTATION_LOCATION).orElse(false);
if (legacyAnnotationLocation && jspecifyMode) {
throw new IllegalStateException(
Expand Down Expand Up @@ -554,6 +558,11 @@ public boolean assertsEnabled() {
return castToNonNullMethod;
}

@Override
public boolean castToNonNullMethodFailsOnNull() {
return castToNonNullMethodFailsOnNull;
}

@Override
public ImmutableSet<String> getSuppressionNameAliases() {
return suppressionNameAliases;
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26 changes: 25 additions & 1 deletion nullaway/src/main/java/com/uber/nullaway/handlers/LibraryModelsHandler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -401,8 +401,32 @@ private void setUnconditionalArgumentNullness(
AccessPath.AccessPathContext apContext) {
ImmutableSet<Integer> requiredNonNullParameters =
getOptLibraryModels(state.context).failIfNullParameters(callee);
Set<Integer> allNonNullParams;
if (config.castToNonNullMethodFailsOnNull()) {
ImmutableSet<Integer> castToNonNullParameters =
getOptLibraryModels(state.context).castToNonNullMethod(callee);
String cliCastToNonNull = config.getCastToNonNullMethod();
boolean isCliCastToNonNull =
cliCastToNonNull != null
&& callee.getParameters().size() == 1
&& cliCastToNonNull.equals(
ASTHelpers.enclosingClass(callee) + "." + callee.getSimpleName());

if (castToNonNullParameters.isEmpty() && !isCliCastToNonNull) {
allNonNullParams = requiredNonNullParameters;
} else {
allNonNullParams = new HashSet<>(requiredNonNullParameters);
allNonNullParams.addAll(castToNonNullParameters);
if (isCliCastToNonNull) {
allNonNullParams.add(0);
}
}
} else {
allNonNullParams = requiredNonNullParameters;
}

for (AccessPath accessPath :
accessPathsAtIndexes(requiredNonNullParameters, arguments, state, apContext)) {
accessPathsAtIndexes(allNonNullParams, arguments, state, apContext)) {
bothUpdates.set(accessPath, NONNULL);
}
}
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118 changes: 118 additions & 0 deletions nullaway/src/test/java/com/uber/nullaway/CoreTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
package com.uber.nullaway;

import java.util.Arrays;
import java.util.List;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
Expand Down Expand Up @@ -397,6 +398,123 @@ Object test4(@Nullable Object o) {
.doTest();
}

@SuppressWarnings("deprecation")
@Test
public void testCastToNonNullPropagationDefault() {
defaultCompilationHelper
.addSourceFile("testdata/Util.java")
.addSourceLines(
"Test.java",
"""
package com.uber;
import javax.annotation.Nullable;
import static com.uber.nullaway.testdata.Util.castToNonNull;
class Test {
static class Foo {
@Nullable String getToken() { return ""; }
}
void test(Foo value) {
if (castToNonNull(value.getToken()).contains("abc")) {
// BUG: Diagnostic contains: dereferenced expression 'value.getToken()' is @Nullable
value.getToken().length();
}
}
}
""")
.doTest();
}

@SuppressWarnings("deprecation")
@Test
public void testCastToNonNullPropagationExplicitFalse() {
makeTestHelperWithArgs(
List.of(
"-d",
temporaryFolder.getRoot().getAbsolutePath(),
"-XepOpt:NullAway:AnnotatedPackages=com.uber",
"-XepOpt:NullAway:CastToNonNullMethod=com.uber.nullaway.testdata.Util.castToNonNull",
"-XepOpt:NullAway:CastToNonNullMethodFailsOnNull=false"))
.addSourceFile("testdata/Util.java")
.addSourceLines(
"Test.java",
"""
package com.uber;
import javax.annotation.Nullable;
import static com.uber.nullaway.testdata.Util.castToNonNull;
class Test {
static class Foo {
@Nullable String getToken() { return ""; }
}
void test(Foo value) {
if (castToNonNull(value.getToken()).contains("abc")) {
// BUG: Diagnostic contains: dereferenced expression 'value.getToken()' is @Nullable
value.getToken().length();
}
}
}
""")
.doTest();
}

@SuppressWarnings("deprecation")
@Test
public void testCastToNonNullPropagationFailsOnNullEnabled() {
makeTestHelperWithArgs(
List.of(
"-d",
temporaryFolder.getRoot().getAbsolutePath(),
"-XepOpt:NullAway:AnnotatedPackages=com.uber",
"-XepOpt:NullAway:CastToNonNullMethod=com.uber.nullaway.testdata.Util.castToNonNull",
"-XepOpt:NullAway:CastToNonNullMethodFailsOnNull=true"))
.addSourceFile("testdata/Util.java")
.addSourceLines(
"Test.java",
"""
package com.uber;
import javax.annotation.Nullable;
import static com.uber.nullaway.testdata.Util.castToNonNull;
class Test {
static class Foo {
@Nullable String getToken() { return ""; }
}
void test(Foo value) {
if (castToNonNull(value.getToken()).contains("abc")) {
value.getToken().length();
}
}
}
""")
.doTest();
}

@Test
public void testObjectsRequireNonNullPropagationUnchanged() {
makeTestHelperWithArgs(
List.of(
"-d",
temporaryFolder.getRoot().getAbsolutePath(),
"-XepOpt:NullAway:AnnotatedPackages=com.uber",
"-XepOpt:NullAway:CastToNonNullMethodFailsOnNull=false"))
.addSourceLines(
"Test.java",
"""
package com.uber;
import java.util.Objects;
import javax.annotation.Nullable;
class Test {
static class Foo {
@Nullable String getToken() { return ""; }
}
void test(Foo value) {
if (Objects.requireNonNull(value.getToken()).contains("abc")) {
value.getToken().length();
}
}
}
""")
.doTest();
}

@Test
public void testReadStaticInConstructor() {
defaultCompilationHelper
Expand Down