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CatarinaGamboaCatarinaGamboa
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allow refence to return values in the to of state refinements for observer methods
1 parent 58349fa commit 15c8287

7 files changed

Lines changed: 178 additions & 3 deletions

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‎liquidjava-example/src/main/java/testSuite/CorrectIteratorReturnHasNext.java‎

Lines changed: 40 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,40 @@
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package testSuite;
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import liquidjava.specification.*;
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@StateSet({"maybeEmpty", "hasNextElem", "empty"})
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public class CorrectIteratorReturnHasNext {
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int index;
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int size;
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@StateRefinement(to = "maybeEmpty(this) && index() == 0 && size() == size")
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CorrectIteratorReturnHasNext(int size) {
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this.size = size;
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this.index = 0;
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}
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@StateRefinement(to = "return ? hasNextElem(this) : empty(this)")
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boolean hasNext() {
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return index < size;
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}
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@StateRefinement(from = "hasNextElem(this)", to = "maybeEmpty(this) && index() == index(old(this)) + 1 && size() == size(old(this))")
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int next() {
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index += 1;
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return index; // return index++; does not work
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}
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int main1() {
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CorrectIteratorReturnHasNext it = new CorrectIteratorReturnHasNext(5);
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int sum = 0;
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while (true){
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if(it.hasNext()){
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sum += it.next();
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} else {
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break;
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}
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}
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return sum;
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}
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}

‎liquidjava-example/src/main/java/testSuite/ErrorIteratorReturnHasNext.java‎

Lines changed: 54 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,54 @@
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package testSuite;
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import liquidjava.specification.*;
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@StateSet({"maybeEmpty", "hasNextElem", "empty"})
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public class ErrorIteratorReturnHasNext {
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int index;
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int size;
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@StateRefinement(to = "maybeEmpty(this) && index() == 0 && size() == size")
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ErrorIteratorReturnHasNext(int size) {
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this.size = size;
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this.index = 0;
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}
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@StateRefinement(to = "return ? hasNextElem(this) : empty(this)")
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boolean hasNext() {
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return index < size;
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}
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@StateRefinement(from = "hasNextElem(this)", to = "maybeEmpty(this) && index() == index(old(this)) + 1 && size() == size(old(this))")
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int next() {
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index += 1;
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return index; // return index++; does not work
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}
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void main1() {
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ErrorIteratorReturnHasNext it = new ErrorIteratorReturnHasNext(5);
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if(it.hasNext()){
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it.next();
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} else {
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it.next(); // State Refinement Error
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}
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}
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void main2() {
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ErrorIteratorReturnHasNext it = new ErrorIteratorReturnHasNext(5);
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it.next(); // State Refinement Error
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}
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int main3() {
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ErrorIteratorReturnHasNext it = new ErrorIteratorReturnHasNext(5);
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int sum = 0;
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while (true){
46+
if(!it.hasNext()){
47+
sum += it.next(); // State Refinement Error
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} else {
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break;
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}
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}
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return sum;
53+
}
54+
}

‎liquidjava-example/src/main/java/testSuite/classes/image_params_so_error/ImageWriteParamsRefinements.java‎

Lines changed: 35 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,35 @@
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package testSuite.classes.image_params_so_error;
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import java.util.Locale;
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import liquidjava.specification.*;
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import javax.imageio.ImageWriteParam;
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@ExternalRefinementsFor("javax.imageio.ImageWriteParam")
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@StateSet({"start", "acceptCompression", "compressionExplicit", "compressionSet"})
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@RefinementAlias("Ratio(float v) { 0 <= v && v <= 1.0 }")
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public interface ImageWriteParamsRefinements {
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@StateRefinement(to="start(this)")
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void ImageWriteParam(Locale locale);
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void setProgressiveMode(
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@Refinement("ImageWriteParam.MODE_DISABLED == mode || mode == ImageWriteParam.MODE_DEFAULT || mode == ImageWriteParam.MODE_COPY_FROM_METADATA")
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int mode
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);
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@StateRefinement(from= "compressionExplicit() || compressionSet()",
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to = "mode == ImageWriteParam.MODE_EXPLICIT ? compressionExplicit(this) : start(this)")
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@StateRefinement(from="acceptCompression()",
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to = "mode == ImageWriteParam.MODE_EXPLICIT ? compressionExplicit(this) : acceptCompression(this)")
27+
void setCompressionMode(int mode);
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@StateRefinement(from="compressionExplicit() || compressionSet()")
30+
void setCompressionQuality(@Refinement("Ratio(_)") float quality);
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@StateRefinement(from = "start(this)",
33+
to = "return ? acceptCompression(this) : start(this)")
34+
boolean canWriteCompressed();
35+
}

‎liquidjava-example/src/main/java/testSuite/classes/image_params_so_error/JpegExporter.java‎

Lines changed: 17 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
1+
package testSuite.classes.image_params_so_error;
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import java.util.Locale;
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4+
import javax.imageio.ImageWriteParam;
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class JpegExporter {
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// Adapted from https://stackoverflow.com/questions/72024965/how-to-compress-jpg-and-png-images-in-java
9+
ImageWriteParam setCompressionPreferences() {
10+
ImageWriteParam param = new ImageWriteParam(Locale.getDefault());
11+
if (param.canWriteCompressed()) {
12+
param.setCompressionMode(ImageWriteParam.MODE_DEFAULT);
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param.setCompressionQuality(0.85f); // State Refinement Error
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}
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return param;
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}
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}

‎liquidjava-verifier/src/main/java/liquidjava/processor/refinement_checker/general_checkers/MethodsFunctionsChecker.java‎

Lines changed: 17 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -289,14 +289,28 @@ private Map<String, String> checkInvocationRefinements(CtElement invocation, Lis
289289
return new HashMap<>();
290290
Map<String, String> map = mapInvocation(arguments, f);
291291

292+
// Stable return-value name so `_`/`return` in @StateRefinement to= matches the post-call VariableInstance.
293+
String returnViName = null;
294+
CtTypeReference<?> retType = f.getType();
295+
if (retType != null && !"void".equals(retType.toString())) {
296+
returnViName = String.format(Formats.INSTANCE, f.getName(), rtc.getContext().getCounter());
297+
invocation.putMetadata(Keys.RETURN_VAR_NAME, returnViName);
298+
if (f.allRefinementsTrue())
299+
rtc.getContext().addInstanceToContext(returnViName, retType, new Predicate(), invocation);
300+
}
301+
292302
if (target != null)
293303
AuxStateHandler.prepareInvocationTarget(rtc, target, invocation);
294304

295305
if (f.allRefinementsTrue()) {
296306
if (target != null)
297307
AuxStateHandler.checkTargetChanges(rtc, f, target, map, invocation);
298308

299-
invocation.putMetadata(Keys.REFINEMENT, new Predicate());
309+
// Expose `_ == returnViName` so the if-condition path variable ties to this return value.
310+
Predicate emptyRef = returnViName != null
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? Predicate.createEquals(Predicate.createVar(Keys.WILDCARD), Predicate.createVar(returnViName))
312+
: new Predicate();
313+
invocation.putMetadata(Keys.REFINEMENT, emptyRef);
300314
return map;
301315
}
302316

@@ -325,7 +339,8 @@ private Map<String, String> checkInvocationRefinements(CtElement invocation, Lis
325339
varName = v.getName();
326340
}
327341

328-
String viName = String.format(Formats.INSTANCE, f.getName(), rtc.getContext().getCounter());
342+
String viName = returnViName != null ? returnViName
343+
: String.format(Formats.INSTANCE, f.getName(), rtc.getContext().getCounter());
329344
VariableInstance vi = (VariableInstance) rtc.getContext().addInstanceToContext(viName, f.getType(),
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methodRef.substituteVariable(Keys.WILDCARD, viName), invocation); // TODO REVIEW!!
331346
if (varName != null && f.hasStateChange() && equalsThis)

‎liquidjava-verifier/src/main/java/liquidjava/processor/refinement_checker/object_checkers/AuxStateHandler.java‎

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -209,12 +209,22 @@ private static Predicate createStatePredicate(String value, String targetClass,
209209
throw new InvalidRefinementError(position, "State refinement transition must be a boolean expression",
210210
value);
211211
}
212+
CtTypeReference<?> returnType = null;
213+
if (isTo && e instanceof CtMethod<?> method) {
214+
CtTypeReference<?> mt = method.getType();
215+
if (mt != null && !"void".equals(mt.toString())) {
216+
p = p.substituteVariable("return", Keys.WILDCARD);
217+
returnType = mt;
218+
}
219+
}
212220
CtTypeReference<?> r = tc.getFactory().Type().createReference(targetClass);
213221
String nameOld = String.format(Formats.INSTANCE, Keys.THIS, tc.getContext().getCounter());
214222
String name = String.format(Formats.INSTANCE, Keys.THIS, tc.getContext().getCounter());
215223
tc.getContext().addVarToContext(Keys.THIS, r, new Predicate(), e);
216224
tc.getContext().addVarToContext(name, r, new Predicate(), e);
217225
tc.getContext().addVarToContext(nameOld, r, new Predicate(), e);
226+
if (returnType != null && !tc.getContext().hasVariable(Keys.WILDCARD))
227+
tc.getContext().addVarToContext(Keys.WILDCARD, returnType, new Predicate(), e);
218228
// TODO REVIEW!!
219229
// what is it for?
220230
Predicate c1 = isTo ? getMissingStates(targetClass, tc, p) : p;
@@ -481,7 +491,10 @@ private static void changeState(TypeChecker tc, VariableInstance vi, List<Object
481491
found = tc.checkStateSMT(prevCheck, expectState, invocation.getPosition());
482492
if (found && stateChange.hasTo()) {
483493
String newInstanceName = String.format(Formats.INSTANCE, name, tc.getContext().getCounter());
484-
Predicate transitionedState = stateChange.getTo().substituteVariable(Keys.WILDCARD, newInstanceName)
494+
// Non-void: `_` is the return value; void: legacy alias for the new instance.
495+
String returnViName = (String) invocation.getMetadata(Keys.RETURN_VAR_NAME);
496+
String wildcardTarget = returnViName != null ? returnViName : newInstanceName;
497+
Predicate transitionedState = stateChange.getTo().substituteVariable(Keys.WILDCARD, wildcardTarget)
485498
.substituteVariable(Keys.THIS, newInstanceName);
486499
for (String s : map.keySet()) {
487500
transitionedState = transitionedState.substituteVariable(s, map.get(s));

‎liquidjava-verifier/src/main/java/liquidjava/utils/constants/Keys.java‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4,6 +4,7 @@ public final class Keys {
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public static final String REFINEMENT = "refinement";
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public static final String REFINEMENT_SAT_CHECK = "refinement_sat_check";
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public static final String TARGET = "target";
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public static final String RETURN_VAR_NAME = "return_var_name";
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public static final String THIS = "this";
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public static final String WILDCARD = "_";
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public static final String OLD = "old";

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