add a %no_suppress_warnings directive

.github/workflows/codeql.yml

@@ -50,6 +50,8 @@ jobs:
         with:
           patterns: |
             -**/LexParse.java:java/local-variable-is-never-read
+            -**/LexScan.java:java/misleading-indentation
+            -**/LexScan.java:java/uncaught-number-format-exception
           input: sarif-results/java.sarif
           output: sarif-results/java.sarif
 

docs/md/lex-specs.md

@@ -86,6 +86,12 @@ generated scanner class.
 
     Makes the generated class abstract.
 
+-   `%no_suppress_warnings`
+
+    Do not generate any `@SuppressWarnings(...)` annotation for the generated
+    class. This means, you can add your own `@SuppressWarnings(...)` annotation
+    in the preamble without getting a compiler error on duplicate annotations.
+
 -   `%apiprivate`
 
     Makes all generated methods and fields of the class private.

javatests/de/jflex/testcase/negation/negation-0.output

@@ -1,3 +1,3 @@
 line: 1 col: 1 match: --aba\u000A--
-action [17] { /* all */ }
+action [22] { /* all */ }
 -1

javatests/de/jflex/testcase/negation/negation-1.output

@@ -1,3 +1,3 @@
 line: 1 col: 1 match: --baba--
-action [17] { /* all */ }
+action [22] { /* all */ }
 -1

javatests/de/jflex/testcase/nevermatch/expected_sysout.txt

@@ -3,11 +3,11 @@ Constructing NFA : 12 states in NFA
 Converting NFA to DFA : 
 .....
 
-Warning in file "javatests/de/jflex/testcase/nevermatch/never.flex" (line 15): 
+Warning in file "javatests/de/jflex/testcase/nevermatch/never.flex" (line 20): 
 Rule can never be matched:
 <A> .    { /* action */ }
 
-Warning in file "javatests/de/jflex/testcase/nevermatch/never.flex" (line 21): 
+Warning in file "javatests/de/jflex/testcase/nevermatch/never.flex" (line 26): 
 Rule can never be matched:
 <A> <<EOF>>  { /* action 4 */ }
 11 states before minimization, 4 states in minimized DFA

javatests/de/jflex/testcase/no_suppress_warnings/BUILD.bazel

@@ -0,0 +1,18 @@
+# Copyright 2023, Gerwin Klein
+# SPDX-License-Identifier: BSD-3-Clause
+
+load("//testsuite:testsuite.bzl", "jflex_testsuite")
+
+jflex_testsuite(
+    name = "NoSuppressTest",
+    srcs = [
+        "NoSuppressTest.java",
+    ],
+    data = [
+        "expected_sysout.txt",
+        "no_suppress.flex",
+    ],
+    deps = [
+        "//third_party/com/google/guava",
+    ],
+)

javatests/de/jflex/testcase/no_suppress_warnings/NoSuppressTest.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2023, Gerwin Klein.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+package de.jflex.testcase.no_suppress_warnings;
+
+import de.jflex.testing.testsuite.JFlexTestRunner;
+import de.jflex.testing.testsuite.annotations.TestSpec;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Test nevermatch warning. */
+@RunWith(JFlexTestRunner.class)
+@TestSpec(lex = "javatests/de/jflex/testcase/no_suppress_warnings/no_suppress.flex", quiet = true)
+public class NoSuppressTest {
+
+  /** Tests that the scanner was successfully generated and can be instantiated. */
+  @Test
+  public void ok() throws Exception {}
+}

javatests/de/jflex/testcase/no_suppress_warnings/no_suppress.flex

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2023, Gerwin Klein <[email protected]>
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+package de.jflex.testcase.no_suppress_warnings;
+
+// will lead to compile error if JFlex emits its own @SuppressWarnings
+@SuppressWarnings("all")
+%%
+
+%no_suppress_warnings
+%class NoSuppress
+%debug
+%int
+
+%%
+
+a|b  { return 1; }
+[^]  { return 0; }

javatests/de/jflex/testcase/semcheck/semcheck-flex.output

@@ -1,5 +1,5 @@
 Reading "javatests/de/jflex/testcase/semcheck/semcheck.flex"
 
-Error in file "javatests/de/jflex/testcase/semcheck/semcheck.flex" (line 12): 
+Error in file "javatests/de/jflex/testcase/semcheck/semcheck.flex" (line 17): 
 Lookahead expression must have match with length of at least 1.
 !"foo" / "bar"  {  }

javatests/de/jflex/testcase/unused_warning/expected_unused_sysout.txt

@@ -1,6 +1,6 @@
 Reading "javatests/de/jflex/testcase/unused_warning/unused.flex"
 
-Warning : Macro "UNUSED" has been declared but never used.
+Warning: Macro "UNUSED" has been declared but never used.
 Constructing NFA : 4 states in NFA
 Converting NFA to DFA : 
 .

jflex/src/main/java/jflex/core/AbstractLexScan.java

@@ -67,6 +67,7 @@ public enum CharSetSize {
   boolean standalone;
   boolean debugOption;
   boolean eofclose;
+  boolean noSuppressWarnings;
 
   String isImplementing;
   String isExtending;
@@ -89,7 +90,6 @@ public UnicodeProperties getUnicodeProperties() {
     return unicodeProperties;
   }
 
-  // TODO(regisd) Return an immutable representation of char classes
   @SuppressWarnings("unused") // Used in generated LexParse
   public CharClasses getCharClasses() {
     return charClasses;
@@ -396,6 +396,10 @@ public int bufferSize() {
     return bufferSize;
   }
 
+  public boolean noSuppressWarnings() {
+    return noSuppressWarnings;
+  }
+
   /**
    * Returns the current line number.
    *

jflex/src/main/java/jflex/generator/Emitter.java

@@ -429,9 +429,10 @@ private void emitUserCode() {
   }
 
   private void emitClassName() {
-    // TODO(#222) Actually fix the fall-through violations
-    println("// See https://github.com/jflex-de/jflex/issues/222");
-    println("@SuppressWarnings(\"FallThrough\")");
+    if (!scanner.noSuppressWarnings()) {
+      // TODO(#222) Actually fix the fall-through violations
+      println("@SuppressWarnings(\"fallthrough\")");
+    }
     if (scanner.isPublic()) print("public ");
 
     if (scanner.isAbstract()) print("abstract ");

jflex/src/main/jflex/LexScan.flex

@@ -281,6 +281,8 @@ DottedVersion =  [1-9][0-9]*(\.[0-9]+){0,2}
   "%warn" {WSP}+ {WarningIdent} {WSP}* { OptionUtils.enableWarning(yytext().substring(6).trim()); }
   "%warn" {WSP}+ {NNL}* { throw new ScannerException(file, ErrorMessages.NOT_A_WARNING_ID, yyline); }
 
+  "%no_suppress_warnings" {WSP}* { noSuppressWarnings = true; }
+
   {Ident}                     { return symbol(IDENT, yytext()); }
   "="{WSP}*                   { yybegin(REGEXP);
                                 return symbol(EQUALS);