Fix #671: Missing newline at end of file should produce a warning (#672)

glankk · web-flow · commit f6947eb7cfda · 2026-07-20T13:42:51.000+02:00
diff --git a/integration_test.py b/integration_test.py
@@ -17,7 +17,7 @@ def __test_relative_header_create_header(dir, with_pragma_once=True):
                 #error header_was_already_included
                 #endif
                 const int dummy = 1;
-                """)
+                """'\n')
     return header_file, "error: #error header_was_already_included"
 
 def __test_relative_header_create_source(dir, include1, include2, is_include1_sys=False, is_include2_sys=False, inv=False):
@@ -31,7 +31,7 @@ def __test_relative_header_create_source(dir, include1, include2, is_include1_sy
                 #undef TEST_H_INCLUDED
                 #include {format_include(include1, is_include1_sys)}
                 #include {format_include(include2, is_include2_sys)}
-                """)
+                """'\n')
     return src_file
 
 @pytest.mark.parametrize("with_pragma_once", (False, True))
@@ -201,27 +201,27 @@ def test_same_name_header(record_property, tmpdir):
                 #include <header_a.h>
                 #include <header_b.h>
                 TEST
-                """)
+                """'\n')
 
     with open(header_a, "wt") as f:
         f.write("""
                 #include "same_name.h"
-                """)
+                """'\n')
 
     with open(header_b, "wt") as f:
         f.write("""
                 #include "same_name.h"
-                """)
+                """'\n')
 
     with open(same_name_a, "wt") as f:
         f.write("""
                 #define TEST E
-                """)
+                """'\n')
 
     with open(same_name_b, "wt") as f:
         f.write("""
                 #define TEST OK
-                """)
+                """'\n')
 
     args = [
         format_include_path_arg(include_a),
@@ -279,13 +279,13 @@ def test_pragma_once_matching(record_property, tmpdir):
         for n in names_to_test:
             f.write(f"""
                     #include {n}
-                    """);
+                    """'\n');
 
     with open(once_header, "wt") as f:
         f.write(f"""
                 #pragma once
                 ONCE
-                """);
+                """'\n');
 
     args = [
         format_include_path_arg(test_dir),
@@ -463,7 +463,7 @@ def test_include_header_twice(tmpdir):
                 #ifdef BBB
                 # error BBB is defined
                 #endif
-                """)
+                """'\n')
 
     test_file = os.path.join(tmpdir, 'test.c')
     with open(test_file, 'wt') as f:
@@ -473,7 +473,7 @@ def test_include_header_twice(tmpdir):
 
                 # define BBB
                 # include "test.h"
-                """)
+                """'\n')
 
     args = [test_file]
 
@@ -507,7 +507,7 @@ def test_define(record_property, tmpdir):  # #589
 def test_utf16_bom(tmpdir):
     test_file = os.path.join(tmpdir, "test.cpp")
     with open(test_file, 'wb') as f:
-        f.write(b'\xFF\xFE\x3B\x00')
+        f.write(b'\xFF\xFE\x3B\x00\x0A\x00')
 
     args = [test_file]
 
diff --git a/main.cpp b/main.cpp
@@ -278,6 +278,14 @@ int main(int argc, char **argv)
             case simplecpp::Output::PORTABILITY_BACKSLASH:
                 std::cerr << "portability: ";
                 break;
+            case simplecpp::Output::PORTABILITY_NO_EOF_NEWLINE:
+                if (simplecpp::getCStd(dui.std) == simplecpp::CUnknown) {
+                    // Only UB for c code, suppress for c++ code
+                    // If no standard is specified then prefer to have a false negative
+                    continue;
+                }
+                std::cerr << "portability: ";
+                break;
             case simplecpp::Output::UNHANDLED_CHAR_ERROR:
                 std::cerr << "unhandled char error: ";
                 break;
diff --git a/simplecpp.cpp b/simplecpp.cpp
@@ -662,6 +662,7 @@ static const std::string COMMENT_END("*/");
 void simplecpp::TokenList::readfile(Stream &stream, const std::string &filename, OutputList *outputList)
 {
     unsigned int multiline = 0U;
+    bool trailing_nl = true;
 
     const Token *oldLastToken = nullptr;
 
@@ -671,6 +672,8 @@ void simplecpp::TokenList::readfile(Stream &stream, const std::string &filename,
         if (!stream.good())
             break;
 
+        trailing_nl = false;
+
         if (ch >= 0x80) {
             if (outputList) {
                 simplecpp::Output err{
@@ -693,6 +696,7 @@ void simplecpp::TokenList::readfile(Stream &stream, const std::string &filename,
             } else {
                 location.line += multiline + 1;
                 multiline = 0U;
+                trailing_nl = true;
             }
             if (!multiline)
                 location.col = 1;
@@ -961,6 +965,15 @@ void simplecpp::TokenList::readfile(Stream &stream, const std::string &filename,
             location.adjust(currentToken);
     }
 
+    if (!trailing_nl && outputList) {
+        Output err{
+            Output::PORTABILITY_NO_EOF_NEWLINE,
+            location,
+            "No newline at end of file."
+        };
+        outputList->emplace_back(std::move(err));
+    }
+
     combineOperators();
 }
 
diff --git a/simplecpp.h b/simplecpp.h
@@ -249,6 +249,7 @@ namespace simplecpp {
             SYNTAX_ERROR,
             DIRECTIVE_AS_MACRO_PARAMETER,
             PORTABILITY_BACKSLASH,
+            PORTABILITY_NO_EOF_NEWLINE,
             UNHANDLED_CHAR_ERROR,
             EXPLICIT_INCLUDE_NOT_FOUND,
             FILE_NOT_FOUND,
diff --git a/test.cpp b/test.cpp
