done all fixed, done report on false positives, wip on true positives
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12 changed files with 179 additions and 122 deletions
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@ -3,4 +3,4 @@
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set -e
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cd /tools/home
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/tools/infer/bin/infer -- mvn compile -Drat.skip=true
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/tools/infer/bin/infer -- mvn compile test -Drat.skip=true -Danimal.sniffer.skip=true
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{"run_sequence":[{"date":"2023-04-11 09:38:59.468025+02:00","command":"run","infer_version":{"major":1,"minor":1,"patch":0,"commit":"f9b6f2b"}}],"results_dir_format":"db_filename: infer-out/results.db\ndb_schema: \n CREATE TABLE IF NOT EXISTS procedures\n ( proc_uid TEXT PRIMARY KEY NOT NULL\n , proc_name BLOB NOT NULL\n , attr_kind INTEGER NOT NULL\n , source_file TEXT NOT NULL\n , proc_attributes BLOB NOT NULL\n , cfg BLOB\n , callees BLOB NOT NULL\n )\n ;\n\n CREATE TABLE IF NOT EXISTS source_files\n ( source_file TEXT PRIMARY KEY\n , type_environment BLOB NOT NULL\n , integer_type_widths BLOB\n , procedure_names BLOB NOT NULL\n , freshly_captured INT NOT NULL )\n ;\n\n CREATE TABLE IF NOT EXISTS specs\n ( proc_uid TEXT PRIMARY KEY NOT NULL\n , proc_name BLOB NOT NULL\n , analysis_summary BLOB NOT NULL\n , report_summary BLOB NOT NULL\n )\n ;\n\n CREATE TABLE IF NOT EXISTS model_specs\n ( proc_uid TEXT PRIMARY KEY NOT NULL\n , proc_name BLOB NOT NULL\n , analysis_summary BLOB NOT NULL\n , report_summary BLOB NOT NULL\n )\n ","should_merge_capture":false}
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{"run_sequence":[{"date":"2023-04-12 13:04:24.635363+02:00","command":"run","infer_version":{"major":1,"minor":1,"patch":0,"commit":"f9b6f2b"}}],"results_dir_format":"db_filename: infer-out/results.db\ndb_schema: \n CREATE TABLE IF NOT EXISTS procedures\n ( proc_uid TEXT PRIMARY KEY NOT NULL\n , proc_name BLOB NOT NULL\n , attr_kind INTEGER NOT NULL\n , source_file TEXT NOT NULL\n , proc_attributes BLOB NOT NULL\n , cfg BLOB\n , callees BLOB NOT NULL\n )\n ;\n\n CREATE TABLE IF NOT EXISTS source_files\n ( source_file TEXT PRIMARY KEY\n , type_environment BLOB NOT NULL\n , integer_type_widths BLOB\n , procedure_names BLOB NOT NULL\n , freshly_captured INT NOT NULL )\n ;\n\n CREATE TABLE IF NOT EXISTS specs\n ( proc_uid TEXT PRIMARY KEY NOT NULL\n , proc_name BLOB NOT NULL\n , analysis_summary BLOB NOT NULL\n , report_summary BLOB NOT NULL\n )\n ;\n\n CREATE TABLE IF NOT EXISTS model_specs\n ( proc_uid TEXT PRIMARY KEY NOT NULL\n , proc_name BLOB NOT NULL\n , analysis_summary BLOB NOT NULL\n , report_summary BLOB NOT NULL\n )\n ","should_merge_capture":false}
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@ -1,22 +1,4 @@
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#0 DONE
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src/main/java/org/apache/commons/lang3/AnnotationUtils.java:72: error: Null Dereference
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object returned by `getAllInterfaces(cls)` could be null and is dereferenced at line 72.
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70. @Override
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71. protected String getShortClassName(final Class<?> cls) {
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72. > for (final Class<?> iface : ClassUtils.getAllInterfaces(cls)) {
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73. if (Annotation.class.isAssignableFrom(iface)) {
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74. return "@" + iface.getName();
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#1 DONE
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:126: error: Null Dereference
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object returned by `getAllInterfaces(cls)` could be null and is dereferenced at line 126.
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124. // superclass field.
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125. Field match = null;
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126. > for (final Class<?> class1 : ClassUtils.getAllInterfaces(cls)) {
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127. try {
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128. final Field test = class1.getField(fieldName);
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#2
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#0
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src/main/java/org/apache/commons/lang3/builder/ReflectionToStringBuilder.java:131: error: Null Dereference
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object `null` is dereferenced by call to `toString(...)` at line 131.
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129. */
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@ -25,7 +7,7 @@ src/main/java/org/apache/commons/lang3/builder/ReflectionToStringBuilder.java:13
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132. }
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133.
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#3 false positive, LONG_TO_INT_RANGE.fit never returns null (may throw NPE when param is null, never the case though as actual param is boxed primitive long)
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#1
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src/main/java/org/apache/commons/lang3/time/DurationUtils.java:142: error: Null Dereference
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object returned by `org.apache.commons.lang3.time.DurationUtils.LONG_TO_INT_RANGE.fit(valueOf(duration.toMillis()))` could be null and is dereferenced at line 142.
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140. Objects.requireNonNull(duration, "duration");
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@ -34,7 +16,7 @@ src/main/java/org/apache/commons/lang3/time/DurationUtils.java:142: error: Null
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143. }
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144.
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#4 false positive, java.lang.String.toCharArray() always returns a non-null char[] object
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#2
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src/main/java/org/apache/commons/lang3/CharSetUtils.java:181: error: Null Dereference
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object `chars` last assigned on line 177 could be null and is dereferenced at line 181.
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179. final char[] chrs = str.toCharArray();
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@ -43,7 +25,7 @@ src/main/java/org/apache/commons/lang3/CharSetUtils.java:181: error: Null Derefe
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182. buffer.append(chr);
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183. }
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#5
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#3
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src/main/java/org/apache/commons/lang3/builder/ToStringBuilder.java:223: error: Null Dereference
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object `null` is dereferenced by call to `ToStringBuilder(...)` at line 223.
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221. */
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@ -52,71 +34,51 @@ src/main/java/org/apache/commons/lang3/builder/ToStringBuilder.java:223: error:
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224. }
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225.
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#6 false positive, Validate.notNull(field, ...) throws NPE if field is null thus if the method is call field is non-null
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:341: error: Null Dereference
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object `field` last assigned on line 338 could be null and is dereferenced by call to `readStaticField(...)` at line 341.
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339. Validate.notNull(field, "Cannot locate field '%s' on %s", fieldName, cls);
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340. // already forced access above, don't repeat it here:
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341. > return readStaticField(field, false);
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342. }
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343.
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#4
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:347: error: Null Dereference
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object `field` last assigned on line 344 could be null and is dereferenced by call to `readStaticField(...)` at line 347.
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345. Validate.notNull(field, "Cannot locate field '%s' on %s", fieldName, cls);
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346. // already forced access above, don't repeat it here:
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347. > return readStaticField(field, false);
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348. }
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349.
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#7 false positive, Validate.notNull(field, ...) throws NPE if field is null thus if the method is call field is non-null
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:385: error: Null Dereference
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object `field` last assigned on line 382 could be null and is dereferenced by call to `readStaticField(...)` at line 385.
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383. Validate.notNull(field, "Cannot locate declared field %s.%s", cls.getName(), fieldName);
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384. // already forced access above, don't repeat it here:
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385. > return readStaticField(field, false);
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386. }
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387.
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#5
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:391: error: Null Dereference
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object `field` last assigned on line 388 could be null and is dereferenced by call to `readStaticField(...)` at line 391.
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389. Validate.notNull(field, "Cannot locate declared field %s.%s", cls.getName(), fieldName);
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390. // already forced access above, don't repeat it here:
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391. > return readStaticField(field, false);
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392. }
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393.
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#8 DONE
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src/main/java/org/apache/commons/lang3/reflect/MethodUtils.java:486: error: Null Dereference
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object returned by `primitiveToWrapper(varArgComponentType)` could be null and is dereferenced by call to `newInstance(...)` at line 486.
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484. final int varArgLength = args.length - methodParameterTypes.length + 1;
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485.
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486. > Object varArgsArray = Array.newInstance(ClassUtils.primitiveToWrapper(varArgComponentType), varArgLength);
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487. // Copy the variadic arguments into the varargs array.
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488. System.arraycopy(args, methodParameterTypes.length - 1, varArgsArray, 0, varArgLength);
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#6
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:605: error: Null Dereference
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object `field` last assigned on line 602 could be null and is dereferenced by call to `writeStaticField(...)` at line 605.
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603. Validate.notNull(field, "Cannot locate field %s on %s", fieldName, cls);
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604. // already forced access above, don't repeat it here:
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605. > writeStaticField(field, value, false);
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606. }
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607.
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#9 false positive, Validate.notNull(field, ...) throws NPE if field is null thus if the method is call field is non-null
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:599: error: Null Dereference
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object `field` last assigned on line 596 could be null and is dereferenced by call to `writeStaticField(...)` at line 599.
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597. Validate.notNull(field, "Cannot locate field %s on %s", fieldName, cls);
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598. // already forced access above, don't repeat it here:
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599. > writeStaticField(field, value, false);
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600. }
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601.
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#7
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:650: error: Null Dereference
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object `field` last assigned on line 647 could be null and is dereferenced by call to `writeField(...)` at line 650.
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648. Validate.notNull(field, "Cannot locate declared field %s.%s", cls.getName(), fieldName);
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649. // already forced access above, don't repeat it here:
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650. > writeField(field, (Object) null, value, false);
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651. }
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652.
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#10 false positive, Validate.notNull(field, ...) throws NPE if field is null thus if the method is call field is non-null
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src/main/java/org/apache/commons/lang3/reflect/FieldUtils.java:644: error: Null Dereference
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object `field` last assigned on line 641 could be null and is dereferenced by call to `writeField(...)` at line 644.
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642. Validate.notNull(field, "Cannot locate declared field %s.%s", cls.getName(), fieldName);
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643. // already forced access above, don't repeat it here:
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644. > writeField(field, (Object) null, value, false);
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645. }
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646.
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#8
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src/main/java/org/apache/commons/lang3/reflect/MethodUtils.java:983: error: Null Dereference
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object `classes` last assigned on line 982 could be null and is dereferenced at line 983.
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981. final Class<?> mcls = method.getDeclaringClass();
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982. final List<Class<?>> classes = getAllSuperclassesAndInterfaces(mcls);
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983. > for (final Class<?> acls : classes) {
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984. final Method equivalentMethod = (ignoreAccess ? MethodUtils.getMatchingMethod(acls, method.getName(), method.getParameterTypes())
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985. : MethodUtils.getMatchingAccessibleMethod(acls, method.getName(), method.getParameterTypes()));
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#11 false positive, getAllSuperclassesAndInterfaces(mcls) is non-null if mcls is non-null, mcls is non-null as java.lang.reflect.Method.getDeclaringClass() is always non-null
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src/main/java/org/apache/commons/lang3/reflect/MethodUtils.java:987: error: Null Dereference
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object `classes` last assigned on line 986 could be null and is dereferenced at line 987.
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985. final Class<?> mcls = method.getDeclaringClass();
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986. final List<Class<?>> classes = getAllSuperclassesAndInterfaces(mcls);
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987. > for (final Class<?> acls : classes) {
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988. final Method equivalentMethod = (ignoreAccess ? MethodUtils.getMatchingMethod(acls, method.getName(), method.getParameterTypes())
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989. : MethodUtils.getMatchingAccessibleMethod(acls, method.getName(), method.getParameterTypes()));
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#12
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src/main/java/org/apache/commons/lang3/concurrent/MultiBackgroundInitializer.java:160: warning: Thread Safety Violation
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Read/Write race. Non-private method `MultiBackgroundInitializer.getTaskCount()` reads without synchronization from container `this.childInitializers` via call to `Map.values()`. Potentially races with write in method `MultiBackgroundInitializer.addInitializer(...)`.
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Reporting because another access to the same memory occurs on a background thread, although this access may not.
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158. int result = 1;
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159.
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160. > for (final BackgroundInitializer<?> bi : childInitializers.values()) {
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161. result += bi.getTaskCount();
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162. }
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Found 13 issues
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Found 9 issues
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Issue Type(ISSUED_TYPE_ID): #
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Null Dereference(NULL_DEREFERENCE): 12
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Thread Safety Violation(THREAD_SAFETY_VIOLATION): 1
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Null Dereference(NULL_DEREFERENCE): 9
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set -e
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cd /tools/home
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/tools/infer/bin/infer -- mvn compile -Drat.skip=true
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/tools/infer/bin/infer -- mvn compile test -Drat.skip=true -Danimal.sniffer.skip=true
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BIN
report.pdf
BIN
report.pdf
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161
report.tex
161
report.tex
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@ -69,7 +69,7 @@ Assignment 1 -- Software Analysis \\\vspace{0.5cm}
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\section{Project selection}
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Given that this assignment draws parallels with the class of Software Design and
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Modelling of last semester, specifically regarding static analyzers, I choose to
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analyze the same project I analyzed in the past with PMD and SonarQube
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analyze the same project I analyzed in the past with PMD and SonarQube using
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Infer\footnote{\url{https://fbinfer.com/}} to make
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for an interesting comparison between static analysis paradigms.
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@ -85,8 +85,8 @@ Commons Lang project focuses on classes that would have fitted in the
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All the source and test classes are contained within in the package
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\textit{org.apache.commons.lang3} or in a sub-package of that package. For the
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sake of brevity, this prefix is omitted from now on when mentioning packages and
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classes in the project.
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sake of brevity, this prefix is omitted from now on when mentioning file paths
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and classes in the project.
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I choose to analyze version 3.12.0 of the library (i.e.\ the code under the
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\textit{git} tag \textit{rel/commons-lang-3.12.0}) because it is the same
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@ -94,9 +94,9 @@ version analyzed during the SDM class.
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To verify that the project satisfies the 5000 lines of code requirement, I run
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the \textit{cloc} tool. Results are shown in table \ref{tab:cloc}. Given the
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project has more than 118,000 lines of code, this requirement is satisfied.
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project has more than 86,000 lines of Java code, this requirement is satisfied.
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\begin{table}[ht]
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\begin{table}[H]
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\centering
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\begin{tabular}{lrrrr}
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\toprule
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@ -118,8 +118,8 @@ project has more than 118,000 lines of code, this requirement is satisfied.
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Total & 518 & 19,270 & 61,280 & 118,526 \\
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\bottomrule
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\end{tabular}
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\caption{Output of the \textit{cloc} tool for the Apache Commons Lang project at
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tag \textit{rel/commons-lang-3.12.0} (before fixes are applied).}
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\caption{Output of the \textit{cloc} tool for the Apache Commons Lang project
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at tag \textit{rel/commons-lang-3.12.0} (before fixes are applied).}
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\label{tab:cloc}
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\end{table}
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@ -132,9 +132,21 @@ The relevant source code to analyze has been copied to the directory
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\href{https://gitlab.com/usi-si-teaching/msde/2022-2023/software-analysis/maggioni/assignment-2}{\textit{usi-si-teaching/msde/2022-2023/software-analysis/maggioni/assignment-2}}
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\end{center}
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on \textit{gitlab.com}. The script \textit{docker-infer.sh} can be ran to
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on \textit{gitlab.com}. The script \textit{docker-infer.sh} can be executed to
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automatically run the Infer tool using default options through the course
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tools docker image \textit{bugcounting/satools:y23}. The analysis outputs
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tools docker image \textit{bugcounting/satools:y23}.
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The script selects Java 17 to compile the project as this is required to not
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make the Animal Sniffer Maven build plugin fail with the message ``This feature
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requires ASM7''.
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The script executes Infer in Maven capture mode executing the \textit{compile}
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and \textit{test} targets while disabling the Apache RAT software license
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checker (which fails for this release). Since unit tests are executed, running
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the script before and after the warning guided refactoring ensures the fixes I
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introduce do not introduce regressions.
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The analysis outputs
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are located in \textit{before/infer-out/report.txt}.
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\section{Results}
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@ -143,47 +155,130 @@ Table \ref{tab:infer} shows the results of the analysis performed by Infer
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providing comments on true and false positives and the actions taken for each
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result.
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In total
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\begin{table}[]
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\begin{table}[H]
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\small
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\begin{tabular}{@{}llp{1.2cm}p{0.8cm}p{6cm}@{}}
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\begin{tabular}{@{}llp{1.2cm}p{0.65cm}p{6cm}@{}}
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\toprule
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\textbf{File} & \textbf{Line} & \textbf{Kind} & \textbf{True Pos.} &
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\textbf{Comment} \\ \midrule
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AnnotationUtils.java & 72 & Null & Yes & -- \\
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reflect/MethodUtils.java & 486 & Null & Yes & -- \\
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reflect/FieldUtils.java & 126 & Null & Yes & -- \\
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concurrent/MultiBackgroundInitializer.java & 160 & Thread Safety & Yes & -- \\
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\textbf{File} & \textbf{Line} & \textbf{Kind} & \textbf{True Pos.} &
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\textbf{Reason why flagged expression is a false positive} \\ \midrule
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AnnotationUtils.java & 72 & Null & Yes & \multirow{4}{6cm}{--} \\
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reflect/MethodUtils.java & 486 & Null & Yes & \\
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reflect/FieldUtils.java & 126 & Null & Yes & \\
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concurrent/MultiBackgroundInitializer.java & 160 & Thread Safety & Yes & \\
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\midrule
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builder/ToStringBuilder.java & 223 & Null & ?? & \multirow{2}{6cm}{??} \\
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builder/ToStringBuilder.java & 223 & Null & No & \multirow{2}{6cm}{Infer flags
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the value \texttt{null} when used as a nullable method argument} \\
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builder/ReflectionToStringBuilder.java & 131 & Null & No & \\
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\midrule
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time/DurationUtils.java & 142 & Null & No & The method which may return a null
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value returns a non-null value if its parameter is non-null, and a
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non-null parameter is given \\
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value returns a non-null value if its parameter is non-null, and a
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non-null parameter is given \\
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\midrule
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CharSetUtils.java & 181 & Null & No & According to \textit{java.lang} documentation, the
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method always returns a non-null value \\
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CharSetUtils.java & 181 & Null & No & According to \textit{java.lang}
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documentation, the method always returns a non-null value \\
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\midrule
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reflect/FieldUtils.java & 341 & Null & No &
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\multirow{4}{6cm}{a utility method is used to guard the dereference reported
|
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with an exception throw} \\
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reflect/FieldUtils.java & 385 & Null & No & \\
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reflect/FieldUtils.java & 599 & Null & No & \\
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reflect/FieldUtils.java & 644 & Null & No & \\
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\multirow{4}{6cm}{A utility method is used to guard the dereference reported
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with an exception throw} \\
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reflect/FieldUtils.java & 385 & Null & No & \\
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reflect/FieldUtils.java & 599 & Null & No & \\
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reflect/FieldUtils.java & 644 & Null & No & \\
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\midrule
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reflect/MethodUtils.java & 987 & Null & No & The method which may return a null
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value returns a non-null value if its parameter is non-null, and a
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non-null parameter is always given according to the \textit{java.lang}
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documentation for the inner nested method \\ \bottomrule
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value returns a non-null value if its parameter is non-null, and a
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non-null parameter is always given according to the \textit{java.lang}
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documentation for the inner nested method \\ \bottomrule
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\end{tabular}
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||||
\caption{Results of the Infer static analysis tool execution with default
|
||||
options. \textit{True Pos.} denotes whether a result is a true positive,
|
||||
while \textit{Kind} denotes with \textit{Null} and \textit{Thread Safety}
|
||||
respectively null dereference issues and thread safety violations.}
|
||||
respectively null dereference warnings and thread safety violations.}
|
||||
\label{tab:infer}
|
||||
\end{table}
|
||||
|
||||
In total Infer reports 13 warnings, 12 of which are null dereference warnings
|
||||
and 1 is a thread safety violation. Of all warnings, 4 are true positives and 9
|
||||
are false positives, resulting in a false positive ratio of over 69\%. These
|
||||
values are summarized in table \ref{tab:num}.
|
||||
|
||||
\begin{table}[H]
|
||||
\centering
|
||||
\begin{tabular}{@{}ll@{}}
|
||||
\toprule
|
||||
Total number of warnings: & 13 \\ \midrule
|
||||
Null dereference warnings: & 12 \\
|
||||
Thread safety violations: & 1 \\ \midrule
|
||||
True positives: & 4 \\
|
||||
False positives: & 9 \\ \bottomrule
|
||||
\end{tabular}
|
||||
\caption{Quantitative results of the static analysis performed by Infer.}
|
||||
\label{tab:num}
|
||||
\end{table}
|
||||
|
||||
\subsection{False Positives}
|
||||
|
||||
As can be deduced from table \ref{tab:infer}, Infer especially struggles at
|
||||
determining Vthe null safety of nested method calls or non-trivial data flow
|
||||
paths. This is sometimes caused by insufficient knowledge of the nullability
|
||||
contracts of the Java standard library (e.g. \textit{java.lang} package).
|
||||
|
||||
In other cases, the flagged expression is guarded by an utility method throwing
|
||||
an exception if its value is indeed \texttt{null}. One of such guards is the
|
||||
\mintinline{java}{static Validate.notNull(Object, String, Object...)} method,
|
||||
which checks if its first argument is null and throws a
|
||||
\texttt{NullPointerException} if so.
|
||||
|
||||
Additionally, Infer seems to struggle with boxed primitives and not
|
||||
understanding that their value is always non-null by construction. As an example
|
||||
I provide the warning reported in the file \textit{time/DurationUtils.java}:
|
||||
|
||||
\begin{listing}[H]
|
||||
\begin{minted}[linenos,firstnumber=139]{java}
|
||||
public static int toMillisInt(final Duration duration) {
|
||||
Objects.requireNonNull(duration, "duration");
|
||||
// intValue() does not do a narrowing conversion here
|
||||
return LONG_TO_INT_RANGE.fit(Long.valueOf(duration.toMillis())).intValue();
|
||||
}
|
||||
\end{minted}
|
||||
\caption{Method \textit{toMillisInt(Duration)} of class
|
||||
\textit{time.DurationUtils} in Apache Commons Lang 3.12.0.}
|
||||
\end{listing}
|
||||
|
||||
Here Infer reports that the first argument of
|
||||
\mintinline{java}{LONG_TO_INT_RANGE.fit(Long)} may be null. However, the return
|
||||
value of \mintinline{java}{Long.valueOf(long)} is always non-null since the
|
||||
method simply boxes its \mintinline{java}{long} argument.
|
||||
|
||||
Finally, some warnings are caused by Infer flagging the use of the \texttt{null}
|
||||
keyword as a method argument for methods that would accept a nullable argument
|
||||
in that position without causing null dereferences. This warning could point to
|
||||
a potential ambiguity is selecting the right method to call at
|
||||
compile time given the argument types (i.e. static dispatching), as
|
||||
\texttt{null} is a valid expression of all object types. For example, in the
|
||||
given class:
|
||||
|
||||
\begin{minted}{java}
|
||||
class C {
|
||||
m(String s) {}
|
||||
m(Object o) {}
|
||||
}
|
||||
\end{minted}
|
||||
|
||||
A call to \mintinline{java}{C.m(null)} would be ambiguous as \texttt{null} is
|
||||
both a \texttt{String} and an \texttt{Object}, thus a cast to either type woule
|
||||
be required to make the code compile. However, the warnings reported by Infer do
|
||||
not present such ambiguity as in those cases overloaded methods have different
|
||||
numbers of parameters. Additionally, even introducing explicit casts for all
|
||||
\texttt{null} arguments does not extinguish the warning. Therefore, I can not
|
||||
find a conclusive explaination on the nature of the false positive, however I
|
||||
can attest to these instances being indeed false positives by having manually
|
||||
verified that the methods in question indeed can accept a null value without
|
||||
causing null dereferences.
|
||||
|
||||
\subsection{True Positives}
|
||||
|
||||
In this section I now cover the warnings that are true positives and thus are
|
||||
causes for refactoring.
|
||||
|
||||
\end{document}
|
||||
|
||||
|
|
|
|||
Reference in a new issue