Fix #14195 Show warning when main() throws an exception (danmar#7887)

Co-authored-by: chrchr-github <[email protected]>

Author: chrchr-github

lib/checkexceptionsafety.cpp

@@ -296,32 +296,35 @@ void CheckExceptionSafety::nothrowThrows()
         if (!function)
             continue;
 
-        // check noexcept and noexcept(true) functions
-        if (function->isNoExcept()) {
-            const Token *throws = functionThrows(function);
-            if (throws)
-                noexceptThrowError(throws);
+        bool isNoExcept = false, isEntryPoint = false;
+        if (function->isNoExcept() || // noexcept and noexcept(true) functions
+            (function->isThrow() && !function->throwArg) || //  throw() functions
+            function->isAttributeNothrow()) { // __attribute__((nothrow)) or __declspec(nothrow) functions
+            isNoExcept = true;
         }
-
-        // check throw() functions
-        else if (function->isThrow() && !function->throwArg) {
-            const Token *throws = functionThrows(function);
-            if (throws)
-                noexceptThrowError(throws);
+        else if (mSettings->library.isentrypoint(function->name())) {
+            isEntryPoint = true;
         }
+        if (!isNoExcept && !isEntryPoint)
+            continue;
 
-        // check __attribute__((nothrow)) or __declspec(nothrow) functions
-        else if (function->isAttributeNothrow()) {
-            const Token *throws = functionThrows(function);
-            if (throws)
+        if (const Token* throws = functionThrows(function)) {
+            if (isEntryPoint)
+                entryPointThrowError(throws);
+            else
                 noexceptThrowError(throws);
         }
     }
 }
 
 void CheckExceptionSafety::noexceptThrowError(const Token * const tok)
 {
-    reportError(tok, Severity::error, "throwInNoexceptFunction", "Exception thrown in function declared not to throw exceptions.", CWE398, Certainty::normal);
+    reportError(tok, Severity::error, "throwInNoexceptFunction", "Unhandled exception thrown in function declared not to throw exceptions.", CWE398, Certainty::normal);
+}
+
+void CheckExceptionSafety::entryPointThrowError(const Token * const tok)
+{
+    reportError(tok, Severity::error, "throwInEntryPoint", "Unhandled exception thrown in function that is an entry point.", CWE398, Certainty::normal);
 }
 
 //--------------------------------------------------------------------------
@@ -433,6 +436,7 @@ void CheckExceptionSafety::getErrorMessages(ErrorLogger *errorLogger, const Sett
     c.rethrowCopyError(nullptr, "varname");
     c.catchExceptionByValueError(nullptr);
     c.noexceptThrowError(nullptr);
+    c.entryPointThrowError(nullptr);
     c.unhandledExceptionSpecificationError(nullptr, nullptr, "funcname");
     c.rethrowNoCurrentExceptionError(nullptr);
 }

lib/checkexceptionsafety.h

@@ -82,6 +82,7 @@ class CPPCHECKLIB CheckExceptionSafety : public Check {
     void rethrowCopyError(const Token * tok, const std::string &varname);
     void catchExceptionByValueError(const Token *tok);
     void noexceptThrowError(const Token * tok);
+    void entryPointThrowError(const Token * tok);
     /** Missing exception specification */
     void unhandledExceptionSpecificationError(const Token * tok1, const Token * tok2, const std::string & funcname);
     /** Rethrow without currently handled exception */

test/testexceptionsafety.cpp

@@ -57,6 +57,7 @@ class TestExceptionSafety : public TestFixture {
         TEST_CASE(rethrowNoCurrentException2);
         TEST_CASE(rethrowNoCurrentException3);
         TEST_CASE(noFunctionCall);
+        TEST_CASE(entryPoint);
     }
 
     struct CheckOptions
@@ -85,7 +86,7 @@ class TestExceptionSafety : public TestFixture {
               "    }\n"
               "};");
         ASSERT_EQUALS("[test.cpp:3:9]: (warning) Class x is not safe, destructor throws exception [exceptThrowInDestructor]\n"
-                      "[test.cpp:3:9]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
+                      "[test.cpp:3:9]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
 
         check("class x {\n"
               "    ~x();\n"
@@ -94,7 +95,7 @@ class TestExceptionSafety : public TestFixture {
               "    throw e;\n"
               "}");
         ASSERT_EQUALS("[test.cpp:5:5]: (warning) Class x is not safe, destructor throws exception [exceptThrowInDestructor]\n"
-                      "[test.cpp:5:5]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
+                      "[test.cpp:5:5]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
 
         // #3858 - throwing exception in try block in destructor.
         check("class x {\n"
@@ -114,7 +115,7 @@ class TestExceptionSafety : public TestFixture {
               "        }\n"
               "    }\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:4:13]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
+        ASSERT_EQUALS("[test.cpp:4:13]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
 
         // #11031 should not warn when noexcept false
         check("class A {\n"
@@ -347,9 +348,9 @@ class TestExceptionSafety : public TestFixture {
               "void func4() noexcept(false) { throw 1; }\n"
               "void func5() noexcept(true) { func1(); }\n"
               "void func6() noexcept(false) { func1(); }");
-        ASSERT_EQUALS("[test.cpp:2:25]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
-                      "[test.cpp:3:31]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
-                      "[test.cpp:5:31]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
+        ASSERT_EQUALS("[test.cpp:2:25]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
+                      "[test.cpp:3:31]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
+                      "[test.cpp:5:31]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
 
         // avoid false positives
         check("const char *func() noexcept { return 0; }\n"
@@ -363,8 +364,8 @@ class TestExceptionSafety : public TestFixture {
               "void func3() throw(int) { throw 1; }\n"
               "void func4() throw() { func1(); }\n"
               "void func5() throw(int) { func1(); }");
-        ASSERT_EQUALS("[test.cpp:2:24]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
-                      "[test.cpp:4:24]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
+        ASSERT_EQUALS("[test.cpp:2:24]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
+                      "[test.cpp:4:24]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
 
         // avoid false positives
         check("const char *func() throw() { return 0; }");
@@ -403,7 +404,7 @@ class TestExceptionSafety : public TestFixture {
               "{\n"
               "    f();\n"
               "}\n", dinit(CheckOptions, $.inconclusive = true));
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:4:5]: (error) Unhandled exception thrown in function that is an entry point. [throwInEntryPoint]\n", errout_str());
     }
 
     void unhandledExceptionSpecification3() {
@@ -420,20 +421,24 @@ class TestExceptionSafety : public TestFixture {
                             "}\n";
 
         check(code, dinit(CheckOptions, $.inconclusive = true));
-        ASSERT_EQUALS("[test.cpp:3:5] -> [test.cpp:1:6]: (style, inconclusive) Unhandled exception specification when calling function f(). [unhandledExceptionSpecification]\n"
+        ASSERT_EQUALS("[test.cpp:10:5]: (error) Unhandled exception thrown in function that is an entry point. [throwInEntryPoint]\n"
+                      "[test.cpp:3:5] -> [test.cpp:1:6]: (style, inconclusive) Unhandled exception specification when calling function f(). [unhandledExceptionSpecification]\n"
                       "[test.cpp:6:5] -> [test.cpp:1:6]: (style, inconclusive) Unhandled exception specification when calling function f(). [unhandledExceptionSpecification]\n", errout_str());
 
         const Settings s = settingsBuilder().library("gnu.cfg").build();
         check(code, dinit(CheckOptions, $.inconclusive = true, $.s = &s));
-        ASSERT_EQUALS("", errout_str());
+        ASSERT_EQUALS("[test.cpp:3:5]: (error) Unhandled exception thrown in function that is an entry point. [throwInEntryPoint]\n"
+                      "[test.cpp:6:5]: (error) Unhandled exception thrown in function that is an entry point. [throwInEntryPoint]\n"
+                      "[test.cpp:10:5]: (error) Unhandled exception thrown in function that is an entry point. [throwInEntryPoint]\n",
+                      errout_str());
     }
 
     void nothrowAttributeThrow() {
         check("void func1() throw(int) { throw 1; }\n"
               "void func2() __attribute((nothrow)); void func2() { throw 1; }\n"
               "void func3() __attribute((nothrow)); void func3() { func1(); }");
-        ASSERT_EQUALS("[test.cpp:2:53]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
-                      "[test.cpp:3:53]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
+        ASSERT_EQUALS("[test.cpp:2:53]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
+                      "[test.cpp:3:53]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
 
         // avoid false positives
         check("const char *func() __attribute((nothrow)); void func1() { return 0; }");
@@ -453,8 +458,8 @@ class TestExceptionSafety : public TestFixture {
         check("void func1() throw(int) { throw 1; }\n"
               "void __declspec(nothrow) func2() { throw 1; }\n"
               "void __declspec(nothrow) func3() { func1(); }");
-        ASSERT_EQUALS("[test.cpp:2:36]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
-                      "[test.cpp:3:36]: (error) Exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
+        ASSERT_EQUALS("[test.cpp:2:36]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n"
+                      "[test.cpp:3:36]: (error) Unhandled exception thrown in function declared not to throw exceptions. [throwInNoexceptFunction]\n", errout_str());
 
         // avoid false positives
         check("const char *func() __attribute((nothrow)); void func1() { return 0; }");
@@ -489,6 +494,31 @@ class TestExceptionSafety : public TestFixture {
               "}\n");
         ASSERT_EQUALS("", errout_str());
     }
+
+    void entryPoint() {
+        check("void f(int i) {\n" // #14195
+              "    if (i < 2)\n"
+              "        throw 0;\n"
+              "}\n"
+              "int main(int argc, char* argv[]) {\n"
+              "    f(argc);\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:6:5]: (error) Unhandled exception thrown in function that is an entry point. [throwInEntryPoint]\n",
+                      errout_str());
+
+        check("void f(int i) {\n"
+              "    if (i < 2)\n"
+              "        throw 0;\n"
+              "}\n"
+              "int main(int argc, char* argv[]) {\n"
+              "    try {\n"
+              "        f(argc);\n"
+              "    } catch (...) {\n"
+              "        return 1;\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
+    }
 };
 
 REGISTER_TEST(TestExceptionSafety)