paho-mqtt v0.12.1 not compatible with >= clang-16 (due to paho-mqtt-sys v0.8.0 dependency)

[dwrobel]

Compiling maho-mqtt-sys on Fedora 38 with clang 16.0.2 fails as follows:

 debug:Using bindgen for Paho C
  debug:clang version: clang version 16.0.2 (Fedora 16.0.2-1.fc38)
  debug:bindgen include path: -I/home/dw/projects/modbus/sun2000-homie/target/release/build/paho-mqtt-sys-69b2a6d9e5bbfd11/out/include

  --- stderr
  fatal: not a git repository (or any parent up to mount point /)
  Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
  gmake[1]: warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.
  thread 'main' panicked at '"__mbstate_t_union_(unnamed_at_/usr/include/bits/types/__mbstate_t_h_16_3)" is not a valid Ident', /home/dw/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.56/src/fallback.rs:811:9

The problem is in bindgen v0.52.0 and was fixed by https://github.com/rust-lang/rust-bindgen/pull/2319 as a result the minimum version of bindgen compatible with clang-16 is v0.62.0.

Once I bump paho-mqtt-sys to 0.8.1 in https://github.com/eclipse/paho.mqtt.rust/blob/058c4f8e020b4741283e3abd8871a2a9c709a401/Cargo.toml#L25 then the compilation succeeded as it changes the dependency on bindgen from:

$ cargo tree -i bindgen
bindgen v0.52.0
[build-dependencies]
└── paho-mqtt-sys v0.8.0
    └── paho-mqtt v0.12.1

to:

$ cargo tree -i bindgen
bindgen v0.64.0
[build-dependencies]
└── paho-mqtt-sys v0.8.1
    └── paho-mqtt v0.12.1

Please consider updating this dependency and release updated version of paho.mqtt crate.

[fpagliughi]

Thanks for reporting this! I was away for most of the summer, but am starting back on some open source projects now, and will get this in with the next set of bug fixes.

[vlnzrv]

This issue saved my day, thank you @dwrobel