Publish flattened headers for Compiler Explorer

[jll63]

(Written by Claude Code, on behalf of @jll63.)

Brings back the flattened headers that were published for the review, and has
CI deploy them again. The scripts that produced them went away with the old
main.yml in 83c8ab9 ("CI: adopt boost-cli GHA"); what was left in dev/ had
gone stale - flatten.sh still named compiler.hpp, shared_ptr.hpp and
unique_ptr.hpp.

What is generated

Compiler Explorer can include a header from a URL, but only one file at a time:
it does not resolve the includes inside the file it fetches, and it does the
fetching client-side, so the host must send CORS headers - GitHub Pages does.

dev/flatten.py therefore rewrites every public header into a self-sufficient
file, so that a CE example's include list is the same as a local example's, one
line per header, in the same order:

#include <https://jll63.github.io/openmethod/boost/openmethod.hpp>
#include <https://jll63.github.io/openmethod/boost/openmethod/initialize.hpp>

boost/openmethod.hpp is the root and carries its whole closure. Every other
header carries only what the root does not provide - its detail/ headers, and
interop/virtual_any.hpp, which nothing includes directly - and turns the rest
into a check on the include guard:

#ifndef BOOST_OPENMETHOD_CORE_HPP
#error "<boost/openmethod/initialize.hpp>: #include <.../boost/openmethod.hpp> first"
#endif

so using one without the root fails on a single #error instead of a wall of
undeclared identifiers. Guard names are read from the header being flattened,
never hardcoded - several are legacy and do not match their path.

Deployment

The antora job regenerates the headers into the Pages artifact, at the root of
the site, next to the documentation. They are live now, from this branch:
https://jll63.github.io/openmethod/boost/openmethod.hpp. Switching the source
to develop later is just a merge - the deploy step is not branch-specific.

Checks

A flat-headers job runs dev/check-flat.sh on every push and PR: each
generated header must compile after the root, each must fail on its own with
our own diagnostic, and the ce/*.cpp examples must build and run against the
generated tree. 50 checks.

ce/ is now part of the CMake build as well. It was referenced from nowhere,
its CMakeLists.txt carried mangled identifiers from a bad sed, and two sources
had been missing using boost::openmethod::virtual_; long enough to stop
compiling.

Reflection example

ce/reflection.cpp registers Animal, Dog, Cat and Bulldog by C++26 reflection -
one BOOST_OPENMETHOD_REGISTER_CLASSES() instead of BOOST_OPENMETHOD_CLASSES.
Bulldog is the point: no overrider mentions it and no class list names it, yet
the scan finds it deriving from Dog, registers it, and poke dispatches it to
Dog's overrider.

It has no C++17 fallback, so CMake builds it only when
BOOST_OPENMETHOD_ENABLE_REFLECTION is on, and dev/check-flat.sh probes for a
P2996 compiler (CXX_REFLECTION, $CXX, then g++-16) and reports it skipped
when there is none. The flat-headers job installs GCC 16 so CI compiles it -
confirmed in the job log:

note   C++26 reflection: g++-16 -std=c++26 -freflection
ok     ce/reflection.cpp

Live on Compiler Explorer: https://godbolt.org/z/1eTx5f13z (x86-64 gcc 16.2,
-std=c++26 -freflection -O3 -DNDEBUG, Boost 1.90). Checked through godbolt's
own compile API, with the fetched flat headers pasted in place of the URL
includes the way CE's client does: exit 0, and the program prints
Snoopy barks. / Felix hisses. / Hector barks.

🤖 Generated with Claude Code

https://claude.ai/code/session_011HmyQexbZAWZk6BDkHSbdQ

[cppalliance-bot]

An automated preview of the documentation is available at https://98.openmethod.prtest3.cppalliance.org/libs/openmethod/doc/html/index.html

If more commits are pushed to the pull request, the docs will rebuild at the same URL.

2026-09-04 21:58:15 UTC

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.46%. Comparing base (92e720c) to head (5ec487c).
⚠️ Report is 19 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop      #98      +/-   ##
===========================================
+ Coverage    93.02%   93.46%   +0.44%     
===========================================
  Files           22       22              
  Lines         1634     1653      +19     
  Branches       504      500       -4     
===========================================
+ Hits          1520     1545      +25     
+ Misses          66       64       -2     
+ Partials        48       44       -4     

see 5 files with indirect coverage changes

---

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