cxx_supportlib build failure with clang++-19 due to invalid member access

[kenballus]

Issue report

Question 1: What is the problem?

The passenger agent fails to build with clang 19.

Steps to reproduce:

0. Start a fresh Fedora 41 container.

docker run --workdir /root --rm -it fedora:41 bash

1. Install dependencies:

yes | dnf install git ruby-devel clang++ libcurl-devel

2. Download and build Passenger with clang++-19:

export CC=clang CXX=clang++
git clone --recurse-submodules https://github.com/phusion/passenger
cd passenger
gem build
gem install ./passenger*.gem
passenger-config compile-agent --auto

3. The build will fail. The log file is long, so I won't paste it all here, but this is the relevant error:

clang++ -o /tmp/passenger-install.4e2qu7/support-binaries/WatchdogMain.o  -Isrc/agent -Isrc/cxx_supportlib -Isrc/cxx_supportlib/vendor-copy -Isrc/cxx_supportlib/vendor-modified -Isrc/cxx_supportlib/vendor-modified/libev -Wno-ambiguous-member-template -DUSE_VENDORED_LIBEV -Isrc/cxx_supportlib/vendor-copy/libuv/include -Isrc/cxx_supportlib/vendor-modified/websocketpp -D_REENTRANT -I/usr/local/include -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-long-long -Wno-missing-field-initializers -Wno-unknown-pragmas -Wno-ambiguous-member-template -fvisibility=hidden -DVISIBILITY_ATTRIBUTE_SUPPORTED -DHAS_ALLOCA_H -DHAVE_ACCEPT4 -DHAS_SFENCE -DHAS_LFENCE -DPASSENGER_DEBUG -DBOOST_DISABLE_ASSERTS -g -fno-limit-debug-info -std=gnu++11 -Wno-unused-local-typedefs -Wno-format-nonliteral -DHAS_UNORDERED_MAP -c src/agent/Watchdog/WatchdogMain.cpp
In file included from src/agent/Watchdog/WatchdogMain.cpp:66:
In file included from src/agent/Shared/ApiServerUtils.h:71:
In file included from src/cxx_supportlib/ServerKit/Server.h:61:
src/cxx_supportlib/Algorithms/MovingAverage.h:193:44: error: no member named 'sumOfWeights' in 'DiscExpMovingAverageWithStddev<alpha, alphaTimeUnit, maxAge>'
  193 |                 return sqrt(copy.sumOfSquaredData / copy.sumOfWeights - pow(copy.average(), 2));
      |                                                     ~~~~ ^
1 error generated.

Question 2: Passenger version and integration mode:

Passenger built from the stable-6.0 branch, commit c7599c4.

Question 3: OS or Linux distro, platform (including version):

Host: Linux 6.1.0-25-amd64, Debian 12
Container: 6.1.0-25-amd64, Fedora 41

Question 4: Passenger installation method:

[X] source tarball

Question 5: Your app's programming language (including any version managers) and framework (including versions):

• For example: Ruby 2.3.0, RVM, Rails 5.0.0; Node.js 4.0.0 with Express 4.13.4

N/A

Question 6: Are you using a PaaS and/or containerization? If so which one?

• For example: Heroku, Amazon Container Services, Docker 1.9 with an image based on passenger-docker

I am using Docker, but only for convenient access to clang 19.

Question 7: Anything else about your setup that we should know?

Nope.

[CamJN]

thanks for this, you can track the fix's progress in the linked PR