CPack/Deb invalid md5sums file fix

Monolithic deb packages were packaged
with invalid md5sums file as trailing
slash in path was causing string replace
to fail and preserve build path.

Fixes #16517

Source/CPack/cmCPackDebGenerator.cxx

@@ -173,7 +173,11 @@ int cmCPackDebGenerator::PackageComponentsAllInOne(
     std::string(this->GetOption("CPACK_PACKAGE_FILE_NAME")) +
     this->GetOutputExtension());
   // all GROUP in one vs all COMPONENT in one
-  localToplevel += "/" + compInstDirName;
+  // if must be here otherwise non component paths have a trailing / while
+  // components don't
+  if (!compInstDirName.empty()) {
+    localToplevel += "/" + compInstDirName;
+  }
 
   /* replace the TEMP DIRECTORY with the component one */
   this->SetOption("CPACK_TEMPORARY_DIRECTORY", localToplevel.c_str());

Tests/RunCMake/CPack/RunCMakeTest.cmake

@@ -23,3 +23,4 @@ run_cpack_test_subtests(SINGLE_DEBUGINFO "no_main_component;one_component;one_co
 run_cpack_source_test(SOURCE_PACKAGE "RPM")
 run_cpack_test(SUGGESTS "RPM" false "MONOLITHIC")
 run_cpack_test(USER_FILELIST "RPM" false "MONOLITHIC")
+run_cpack_test(MD5SUMS "DEB" false "MONOLITHIC;COMPONENT")

Tests/RunCMake/CPack/tests/MD5SUMS/ExpectedFiles.cmake

@@ -0,0 +1,2 @@
+set(EXPECTED_FILES_COUNT "1")
+set(EXPECTED_FILE_CONTENT_1_LIST "/usr;/usr/foo;/usr/foo/CMakeLists.txt")

Tests/RunCMake/CPack/tests/MD5SUMS/VerifyResult.cmake

@@ -0,0 +1,3 @@
+set(whitespaces_ "[\t\n\r ]*")
+set(md5sums_md5sums "^.* usr/foo/CMakeLists\.txt${whitespaces_}$")
+verifyDebControl("${FOUND_FILE_1}" "md5sums" "md5sums")

Tests/RunCMake/CPack/tests/MD5SUMS/test.cmake

@@ -0,0 +1,5 @@
+install(FILES CMakeLists.txt DESTINATION foo COMPONENT test)
+
+if(PACKAGING_TYPE STREQUAL "COMPONENT")
+  set(CPACK_COMPONENTS_ALL test)
+endif()