1 /*
2 * Copyright (c) 2005, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.code;
27
28 import java.util.Arrays;
29 import java.util.EnumSet;
30 import java.util.Map;
31 import java.util.Optional;
32 import java.util.concurrent.ConcurrentHashMap;
33 import java.util.stream.Stream;
34
35 import com.sun.tools.javac.main.Option;
36 import com.sun.tools.javac.tree.JCTree.*;
37 import com.sun.tools.javac.util.Assert;
38 import com.sun.tools.javac.util.Context;
39 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
40 import com.sun.tools.javac.util.JCDiagnostic.LintWarning;
41 import com.sun.tools.javac.util.Log;
42 import com.sun.tools.javac.util.Names;
43 import com.sun.tools.javac.util.Options;
44
45 /**
46 * A class for handling -Xlint suboptions and @SuppressWarnings.
47 *
48 * <p><b>This is NOT part of any supported API.
49 * If you write code that depends on this, you do so at your own risk.
50 * This code and its internal interfaces are subject to change or
51 * deletion without notice.</b>
52 */
53 public class Lint {
54
55 /** The context key for the root Lint object. */
56 protected static final Context.Key<Lint> lintKey = new Context.Key<>();
57
58 /** Get the root Lint instance. */
59 public static Lint instance(Context context) {
60 Lint instance = context.get(lintKey);
61 if (instance == null)
62 instance = new Lint(context);
63 return instance;
64 }
65
66 /**
67 * Obtain an instance with additional warning supression applied from any
68 * @SuppressWarnings and/or @Deprecated annotations on the given symbol.
69 *
70 * <p>
71 * The returned instance will be different from this instance if and only if
72 * {@link #suppressionsFrom} returns a non-empty set.
73 *
74 * @param sym symbol
75 * @return lint instance with new warning suppressions applied, or this instance if none
76 */
77 public Lint augment(Symbol sym) {
78 EnumSet<LintCategory> suppressions = suppressionsFrom(sym);
79 if (!suppressions.isEmpty()) {
80 Lint lint = new Lint(this);
81 lint.values.removeAll(suppressions);
82 lint.suppressedValues.addAll(suppressions);
83 return lint;
84 }
85 return this;
86 }
87
88 /**
89 * Returns a new Lint that has the given LintCategorys enabled.
90 * @param lc one or more categories to be enabled
91 */
92 public Lint enable(LintCategory... lc) {
93 Lint l = new Lint(this);
94 l.values.addAll(Arrays.asList(lc));
95 l.suppressedValues.removeAll(Arrays.asList(lc));
96 return l;
97 }
98
99 /**
100 * Returns a new Lint that has the given LintCategorys suppressed.
101 * @param lc one or more categories to be suppressed
102 */
103 public Lint suppress(LintCategory... lc) {
104 Lint l = new Lint(this);
105 l.values.removeAll(Arrays.asList(lc));
106 l.suppressedValues.addAll(Arrays.asList(lc));
107 return l;
108 }
109
110 private final Context context;
111 private final Options options;
112 private final Log log;
113
114 // These are initialized lazily to avoid dependency loops
115 private Symtab syms;
116 private Names names;
117
118 // Invariant: it's never the case that a category is in both "values" and "suppressedValues"
119 private EnumSet<LintCategory> values;
120 private EnumSet<LintCategory> suppressedValues;
121
122 private static final Map<String, LintCategory> map = new ConcurrentHashMap<>(20);
123
124 @SuppressWarnings("this-escape")
125 protected Lint(Context context) {
126 this.context = context;
127 context.put(lintKey, this);
128 options = Options.instance(context);
129 log = Log.instance(context);
130 }
131
132 // Instantiate a non-root ("symbol scoped") instance
133 protected Lint(Lint other) {
134 other.initializeRootIfNeeded();
135 this.context = other.context;
136 this.options = other.options;
137 this.log = other.log;
138 this.syms = other.syms;
139 this.names = other.names;
140 this.values = other.values.clone();
141 this.suppressedValues = other.suppressedValues.clone();
142 }
143
144 // Process command line options on demand to allow use of root Lint early during startup
145 private void initializeRootIfNeeded() {
146
147 // Already initialized?
148 if (values != null)
149 return;
150
151 // Initialize enabled categories based on "-Xlint" flags
152 if (options.isSet(Option.XLINT) || options.isSet(Option.XLINT_CUSTOM, "all")) {
153 // If -Xlint or -Xlint:all is given, enable all categories by default
154 values = EnumSet.allOf(LintCategory.class);
155 } else if (options.isSet(Option.XLINT_CUSTOM, "none")) {
156 // if -Xlint:none is given, disable all categories by default
157 values = LintCategory.newEmptySet();
158 } else {
159 // otherwise, enable on-by-default categories
160 values = LintCategory.newEmptySet();
161
162 Source source = Source.instance(context);
163 if (source.compareTo(Source.JDK9) >= 0) {
164 values.add(LintCategory.DEP_ANN);
165 }
166 if (Source.Feature.REDUNDANT_STRICTFP.allowedInSource(source)) {
167 values.add(LintCategory.STRICTFP);
168 }
169 values.add(LintCategory.REQUIRES_TRANSITIVE_AUTOMATIC);
170 values.add(LintCategory.OPENS);
171 values.add(LintCategory.MODULE);
172 values.add(LintCategory.REMOVAL);
173 if (!options.isSet(Option.PREVIEW)) {
174 values.add(LintCategory.PREVIEW);
175 }
176 values.add(LintCategory.SYNCHRONIZATION);
177 values.add(LintCategory.INCUBATING);
178 }
179
180 // Look for specific overrides
181 for (LintCategory lc : LintCategory.values()) {
182 if (options.isSet(Option.XLINT_CUSTOM, lc.option)) {
183 values.add(lc);
184 } else if (options.isSet(Option.XLINT_CUSTOM, "-" + lc.option)) {
185 values.remove(lc);
186 }
187 }
188
189 suppressedValues = LintCategory.newEmptySet();
190 }
191
192 @Override
193 public String toString() {
194 initializeRootIfNeeded();
195 return "Lint:[enable" + values + ",suppress" + suppressedValues + "]";
196 }
197
198 /**
199 * Categories of warnings that can be generated by the compiler.
200 */
201 public enum LintCategory {
202 /**
203 * Warn when code refers to a auxiliary class that is hidden in a source file (ie source file name is
204 * different from the class name, and the type is not properly nested) and the referring code
205 * is not located in the same source file.
206 */
207 AUXILIARYCLASS("auxiliaryclass"),
208
209 /**
210 * Warn about use of unnecessary casts.
211 */
212 CAST("cast"),
213
214 /**
215 * Warn about issues related to classfile contents
216 */
217 CLASSFILE("classfile"),
218
219 /**
220 * Warn about "dangling" documentation comments,
221 * not attached to any declaration.
222 */
223 DANGLING_DOC_COMMENTS("dangling-doc-comments"),
224
225 /**
226 * Warn about use of deprecated items.
227 */
228 DEPRECATION("deprecation"),
229
230 /**
231 * Warn about items which are documented with an {@code @deprecated} JavaDoc
232 * comment, but which do not have {@code @Deprecated} annotation.
233 */
234 DEP_ANN("dep-ann"),
235
236 /**
237 * Warn about division by constant integer 0.
238 */
239 DIVZERO("divzero"),
240
241 /**
242 * Warn about empty statement after if.
243 */
244 EMPTY("empty"),
245
246 /**
247 * Warn about issues regarding module exports.
248 */
249 EXPORTS("exports"),
250
251 /**
252 * Warn about falling through from one case of a switch statement to the next.
253 */
254 FALLTHROUGH("fallthrough"),
255
256 /**
257 * Warn about finally clauses that do not terminate normally.
258 */
259 FINALLY("finally"),
260
261 /**
262 * Warn about use of incubating modules.
263 */
264 INCUBATING("incubating"),
265
266 /**
267 * Warn about compiler possible lossy conversions.
268 */
269 LOSSY_CONVERSIONS("lossy-conversions"),
270
271 /**
272 * Warn about compiler generation of a default constructor.
273 */
274 MISSING_EXPLICIT_CTOR("missing-explicit-ctor"),
275
276 /**
277 * Warn about module system related issues.
278 */
279 MODULE("module"),
280
281 /**
282 * Warn about issues regarding module opens.
283 */
284 OPENS("opens"),
285
286 /**
287 * Warn about issues relating to use of command line options
288 */
289 OPTIONS("options"),
290
291 /**
292 * Warn when any output file is written to more than once.
293 */
294 OUTPUT_FILE_CLASH("output-file-clash"),
295
296 /**
297 * Warn about issues regarding method overloads.
298 */
299 OVERLOADS("overloads"),
300
301 /**
302 * Warn about issues regarding method overrides.
303 */
304 OVERRIDES("overrides"),
305
306 /**
307 * Warn about invalid path elements on the command line.
308 * Such warnings cannot be suppressed with the SuppressWarnings
309 * annotation.
310 */
311 PATH("path"),
312
313 /**
314 * Warn about issues regarding annotation processing.
315 */
316 PROCESSING("processing"),
317
318 /**
319 * Warn about unchecked operations on raw types.
320 */
321 RAW("rawtypes"),
322
323 /**
324 * Warn about use of deprecated-for-removal items.
325 */
326 REMOVAL("removal"),
327
328 /**
329 * Warn about use of automatic modules in the requires clauses.
330 */
331 REQUIRES_AUTOMATIC("requires-automatic"),
332
333 /**
334 * Warn about automatic modules in requires transitive.
335 */
336 REQUIRES_TRANSITIVE_AUTOMATIC("requires-transitive-automatic"),
337
338 /**
339 * Warn about Serializable classes that do not provide a serial version ID.
340 */
341 SERIAL("serial"),
342
343 /**
344 * Warn about issues relating to use of statics
345 */
346 STATIC("static"),
347
348 /**
349 * Warn about unnecessary uses of the strictfp modifier
350 */
351 STRICTFP("strictfp"),
352
353 /**
354 * Warn about synchronization attempts on instances of @ValueBased classes.
355 */
356 SYNCHRONIZATION("synchronization"),
357
358 /**
359 * Warn about issues relating to use of text blocks
360 */
361 TEXT_BLOCKS("text-blocks"),
362
363 /**
364 * Warn about possible 'this' escapes before subclass instance is fully initialized.
365 */
366 THIS_ESCAPE("this-escape"),
367
368 /**
369 * Warn about issues relating to use of try blocks (i.e. try-with-resources)
370 */
371 TRY("try"),
372
373 /**
374 * Warn about unchecked operations on raw types.
375 */
376 UNCHECKED("unchecked"),
377
378 /**
379 * Warn about potentially unsafe vararg methods
380 */
381 VARARGS("varargs"),
382
383 /**
384 * Warn about use of preview features.
385 */
386 PREVIEW("preview"),
387
388 /**
389 * Warn about use of restricted methods.
390 */
391 RESTRICTED("restricted");
392
393 LintCategory(String option) {
394 this.option = option;
395 map.put(option, this);
396 }
397
398 /**
399 * Get the {@link LintCategory} having the given command line option.
400 *
401 * @param option lint category option string
402 * @return corresponding {@link LintCategory}, or empty if none exists
403 */
404 public static Optional<LintCategory> get(String option) {
405 return Optional.ofNullable(map.get(option));
406 }
407
408 public static EnumSet<LintCategory> newEmptySet() {
409 return EnumSet.noneOf(LintCategory.class);
410 }
411
412 /** Get the string representing this category in @SuppressAnnotations and -Xlint options. */
413 public final String option;
414 }
415
416 /**
417 * Checks if a warning category is enabled. A warning category may be enabled
418 * on the command line, or by default, and can be temporarily disabled with
419 * the SuppressWarnings annotation.
420 */
421 public boolean isEnabled(LintCategory lc) {
422 initializeRootIfNeeded();
423 return values.contains(lc);
424 }
425
426 /**
427 * Checks is a warning category has been specifically suppressed, by means
428 * of the SuppressWarnings annotation, or, in the case of the deprecated
429 * category, whether it has been implicitly suppressed by virtue of the
430 * current entity being itself deprecated.
431 */
432 public boolean isSuppressed(LintCategory lc) {
433 initializeRootIfNeeded();
434 return suppressedValues.contains(lc);
435 }
436
437 /**
438 * Helper method. Log a lint warning if its lint category is enabled.
439 *
440 * @param warning key for the localized warning message
441 */
442 public void logIfEnabled(LintWarning warning) {
443 logIfEnabled(null, warning);
444 }
445
446 /**
447 * Helper method. Log a lint warning if its lint category is enabled.
448 *
449 * @param pos source position at which to report the warning
450 * @param warning key for the localized warning message
451 */
452 public void logIfEnabled(DiagnosticPosition pos, LintWarning warning) {
453 if (isEnabled(warning.getLintCategory())) {
454 log.warning(pos, warning);
455 }
456 }
457
458 /**
459 * Obtain the set of recognized lint warning categories suppressed at the given symbol's declaration.
460 *
461 * <p>
462 * This set can be non-empty only if the symbol is annotated with either
463 * @SuppressWarnings or @Deprecated.
464 *
465 * @param symbol symbol corresponding to a possibly-annotated declaration
466 * @return new warning suppressions applied to sym
467 */
468 public EnumSet<LintCategory> suppressionsFrom(Symbol symbol) {
469 EnumSet<LintCategory> suppressions = suppressionsFrom(symbol.getDeclarationAttributes().stream());
470 if (symbol.isDeprecated() && symbol.isDeprecatableViaAnnotation())
471 suppressions.add(LintCategory.DEPRECATION);
472 return suppressions;
473 }
474
475 /**
476 * Retrieve the recognized lint categories suppressed by the given @SuppressWarnings annotation.
477 *
478 * @param annotation @SuppressWarnings annotation, or null
479 * @return set of lint categories, possibly empty but never null
480 */
481 private EnumSet<LintCategory> suppressionsFrom(JCAnnotation annotation) {
482 initializeSymbolsIfNeeded();
483 if (annotation == null)
484 return LintCategory.newEmptySet();
485 Assert.check(annotation.attribute.type.tsym == syms.suppressWarningsType.tsym);
486 return suppressionsFrom(Stream.of(annotation).map(anno -> anno.attribute));
487 }
488
489 // Find the @SuppressWarnings annotation in the given stream and extract the recognized suppressions
490 private EnumSet<LintCategory> suppressionsFrom(Stream<Attribute.Compound> attributes) {
491 initializeSymbolsIfNeeded();
492 EnumSet<LintCategory> result = LintCategory.newEmptySet();
493 attributes
494 .filter(attribute -> attribute.type.tsym == syms.suppressWarningsType.tsym)
495 .map(this::suppressionsFrom)
496 .forEach(result::addAll);
497 return result;
498 }
499
500 // Given a @SuppressWarnings annotation, extract the recognized suppressions
501 private EnumSet<LintCategory> suppressionsFrom(Attribute.Compound suppressWarnings) {
502 EnumSet<LintCategory> result = LintCategory.newEmptySet();
503 Attribute.Array values = (Attribute.Array)suppressWarnings.member(names.value);
504 for (Attribute value : values.values) {
505 Optional.of((String)((Attribute.Constant)value).value)
506 .flatMap(LintCategory::get)
507 .ifPresent(result::add);
508 }
509 return result;
510 }
511
512 private void initializeSymbolsIfNeeded() {
513 if (syms == null) {
514 syms = Symtab.instance(context);
515 names = Names.instance(context);
516 }
517 }
518 }