From b70efec1af718f332f0168a2469ecf6026407bf1 Mon Sep 17 00:00:00 2001
From: guwirth <guenter.wirth@etas.com>
Date: Fri, 19 May 2023 12:00:37 +0200
Subject: [PATCH] correct handling of # in preprocessor Check if # is the first
 token in the line, only then it is a preprocessor command. Otherwise it is a
 special character which is treated e.g. in macros like any other string.

---
 .../sonar/cxx/channels/PreprocessorChannel.java |  8 ++++++++
 .../lexer/CxxLexerWithPreprocessingTest.java    | 17 +++++++++++++++++
 .../lexer/CxxLexerWithoutPreprocessorTest.java  |  3 +++
 3 files changed, 28 insertions(+)

diff --git a/cxx-squid/src/main/java/org/sonar/cxx/channels/PreprocessorChannel.java b/cxx-squid/src/main/java/org/sonar/cxx/channels/PreprocessorChannel.java
index b41ddb5d5d..0f8822d4bb 100644
--- a/cxx-squid/src/main/java/org/sonar/cxx/channels/PreprocessorChannel.java
+++ b/cxx-squid/src/main/java/org/sonar/cxx/channels/PreprocessorChannel.java
@@ -57,6 +57,14 @@ public boolean consume(CodeReader code, Lexer output) {
     int line = code.getLinePosition();
     int column = code.getColumnPosition();
 
+    // if there was already a token in the line it's not a preprocessor command
+    var previousTokens = output.getTokens();
+    if (!previousTokens.isEmpty()) {
+      if (previousTokens.get(previousTokens.size() - 1).getLine() == line) {
+        return false;
+      }
+    }
+
     if (code.popTo(matcher, sb) <= 0) {
       return false;
     }
diff --git a/cxx-squid/src/test/java/org/sonar/cxx/lexer/CxxLexerWithPreprocessingTest.java b/cxx-squid/src/test/java/org/sonar/cxx/lexer/CxxLexerWithPreprocessingTest.java
index bcb099d098..f71a2be4b0 100644
--- a/cxx-squid/src/test/java/org/sonar/cxx/lexer/CxxLexerWithPreprocessingTest.java
+++ b/cxx-squid/src/test/java/org/sonar/cxx/lexer/CxxLexerWithPreprocessingTest.java
@@ -1030,4 +1030,21 @@ void string_problem_1903() {
     softly.assertAll();
   }
 
+  @Test
+  void undefined_macro_with_hash_parameter() {
+    List<Token> tokens = lexer.lex("BOOST_PP_EXPAND(#) define BOOST_FT_config_valid 1");
+    assertThat(tokens).hasSize(8);
+  }
+
+  @Test
+  void defined_macro_with_hash_parameter() {
+    List<Token> tokens = lexer.lex("#define BOOST_PP_EXPAND(p) p\n"
+                                     + "BOOST_PP_EXPAND(#) define BOOST_FT_config_valid 1\n"
+                                     + "BOOST_FT_config_valid");
+
+    assertThat(tokens).anySatisfy(token -> assertThat(token)
+      .isValue("1")
+      .hasType(CxxTokenType.NUMBER));
+  }
+
 }
diff --git a/cxx-squid/src/test/java/org/sonar/cxx/lexer/CxxLexerWithoutPreprocessorTest.java b/cxx-squid/src/test/java/org/sonar/cxx/lexer/CxxLexerWithoutPreprocessorTest.java
index 4cdbf7cb79..0d74061753 100644
--- a/cxx-squid/src/test/java/org/sonar/cxx/lexer/CxxLexerWithoutPreprocessorTest.java
+++ b/cxx-squid/src/test/java/org/sonar/cxx/lexer/CxxLexerWithoutPreprocessorTest.java
@@ -40,6 +40,9 @@ public void init() {
   @Test
   void preprocessor_directives() {
     var softly = new SoftAssertions();
+
+    softly.assertThat(lexer.lex("#")).anySatisfy(token -> assertThat(token).isValue(
+      "#").hasType(CxxTokenType.PREPROCESSOR));
     softly.assertThat(lexer.lex("#include <iostream>")).anySatisfy(token -> assertThat(token).isValue(
       "#include <iostream>").hasType(CxxTokenType.PREPROCESSOR));
     softly.assertThat(lexer.lex("# include <iostream>")).anySatisfy(token -> assertThat(token).isValue(