CMake uninitialized variable warnings

[bryan-lipinski]

What version of protobuf and what language are you using?
Version: main
Language: C++

What operating system (Linux, Windows, ...) and version?

Windows 11 24H2

What runtime / compiler are you using (e.g., python version or gcc version)

cmake 3.30.5
msvc 19.41.34123.0

What did you do?
Steps to reproduce the behavior:

find_package(Protobuf CONFIG)

Configure CMake using '--warn-uninitialized'

What did you expect to see

No warnings/errors

What did you see instead?

CMake Error (dev) vcpkg_installed/x64-windows-target/share/protobuf/protobuf-config-version.cmake:7 (set):
  uninitialized variable 'Protobuf_FIND_VERSION_PRERELEASE'
Call Stack (most recent call first):
  vcpkg_installed/x64-windows-target/share/protobuf/vcpkg-cmake-wrapper.cmake:3 (_find_package)
  cmake/tools/VCPkg/scripts/buildsystems/vcpkg.cmake:811 (include)

CMake Error (dev) at vcpkg_installed/x64-windows-target/share/protobuf/protobuf-config-version.cmake:11 (set):
  uninitialized variable 'Protobuf_FIND_VERSION_PRERELEASE'
Call Stack (most recent call first):
  vcpkg_installed/x64-windows-target/share/protobuf/vcpkg-cmake-wrapper.cmake:3 (_find_package)
  cmake/tools/VCPkg/scripts/buildsystems/vcpkg.cmake:811 (include)

CMake Error (dev) at vcpkg_installed/x64-windows-target/share/protobuf/protobuf-module.cmake:188 (set):
  uninitialized variable 'Protobuf_SRC_ROOT_FOLDER'
Call Stack (most recent call first):
  vcpkg_installed/x64-windows-target/share/protobuf/protobuf-config.cmake:21 (include)
  vcpkg_installed/x64-windows-target/share/protobuf/vcpkg-cmake-wrapper.cmake:3 (_find_package)
  cmake/tools/VCPkg/scripts/buildsystems/vcpkg.cmake:811 (include)

// Same error for:
//   Protobuf_IMPORT_DIRS
//   Protobuf_DEBUG
//   Protobuf_INCLUDE_DIR
//   Protobuf_LIBRARY_DEBUG
//   Protobuf_PROTOC_LIBRARY_DEBUG
//   Protobuf_LITE_LIBRARY_DEBUG

Make sure you include information that can help us debug (full error message, exception listing, stack trace, logs).

The first two warnings are related to #1778. However, that change failed to correct the similar variable dereference in the subsequent 'set'.

Code

# Prerelease versions cannot be passed in directly via the find_package command,
# so we allow users to specify it in a variable
if(NOT DEFINED "${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE")  // fixed
  set("${${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE}" "")  // not fixed
else()

The remaining warnings are due to the camel case to uppercase conversion dereferencing variables that weren't set.

Code

    string(TOUPPER ${Camel} UPPER)
    set(${UPPER} ${${Camel}})   // No check that ${Camel} is defined

Anything else we should know about your project / environment

[bryan-lipinski]

Here's the patch I'm currently using to workaround the issue. However, I wasn't sure of what behavior the set(${UPPER} call should have if ${Camel} is undefined.