Remaining -Wconversion warnings

[miketsts]

Hi,

After my PR introducing -Wconversion compilation flag a couple of weeks ago, there still remain a couple of warnings that I don't know how to resolve:

In file included from /home/user/pistache/src/common/http_defs.cc:11:0:
/home/user/pistache/include/pistache/date.h: In constructor ‘constexpr date::weekday_indexed::weekday_indexed(const date::weekday&, unsigned int)’:
/home/user/pistache/include/pistache/date.h:1641:11: warning: conversion to ‘unsigned char:4’ from ‘unsigned char’ may alter its value [-Wconversion]
     : wd_(static_cast<decltype(wd_)>(static_cast<unsigned>(wd))),
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/user/pistache/include/pistache/date.h:1642:14: warning: conversion to ‘unsigned char:4’ from ‘unsigned char’ may alter its value [-Wconversion]
       index_(static_cast<decltype(index_)>(index)) {}
              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is conversion warning from "unsigned char" to bitfield 'unsigned char:4'. There is already static_cast<decltype(index_)> - apparently this doesn't work. It looks like the following fixes these warnings:

@@ -1638,8 +1638,8 @@ inline bool weekday_indexed::ok() const NOEXCEPT {
 CONSTCD11
 inline weekday_indexed::weekday_indexed(const date::weekday &wd,
                                         unsigned index) NOEXCEPT
-    : wd_(static_cast<decltype(wd_)>(static_cast<unsigned>(wd))),
-      index_(static_cast<decltype(index_)>(index)) {}
+    : wd_(static_cast<unsigned>(wd) & 0xF),
+      index_(index & 0xF) {}

Any comments?

[ 69%] Building CXX object src/CMakeFiles/pistache.dir/common/http.cc.o
In file included from /home/user/pistache/include/pistache/http.h:20:0,
                 from /home/user/pistache/src/common/http.cc:8:
/home/user/pistache/include/pistache/async.h: In instantiation of ‘void Pistache::Async::Private::impl::Continuation<T, Resolve, Reject, Pistache::Async::Promise<U>(Args ...)>::doResolve(const std::shared_ptr<Pistache::Async::Private::CoreT<T> >&) [with T = long int; Resolve = std::function<Pistache::Async::Promise<long int>(int)>; Reject = std::function<void(std::__exception_ptr::exception_ptr&)>; U = long int; Args = {int}]’:
/home/user/pistache/src/common/http.cc:1008:1:   required from here
/home/user/pistache/include/pistache/async.h:465:10: warning: conversion to ‘int’ from ‘long int’ may alter its value [-Wconversion]
     auto promise = resolve_(detail::tryMove<Resolve>(core->value()));
          ^~~~~~~

This one deals with hard core templating in Pistache, and I'm didn't succeed to get to the root.

Thanks a lot

[dennisjenkins75]

Ignore everything in date.h. We did not write it; it was imported from some other place. I should move it from "include/pistache" into "include/pistache/thirdparty".

I've not dug into the code (this is just a drive-by comment), but I'm surprised about the warning for the "auto promise =". Why did the compiler fail to create the desired type?

Does this warning occur on both GCC-9 and Clang-?

[miketsts]

I run gcc 7, I don't have the other environments, sorry.
And warnings appear in my compilation out, as I compile pistache from source as git submodule. So I can't just ignore them - or we need to do something in CMakeLists.txt.

Actually, it was my commit a couple of weeks ago that added -Wconversion - maybe we need to remove it eventually?

[miketsts]

I found that the following change fixes the warning in async.h:

diff --git a/src/common/http.cc b/src/common/http.cc
index b8728aa..499f352 100644
--- a/src/common/http.cc
+++ b/src/common/http.cc
@@ -794,7 +794,7 @@ Async::Promise<ssize_t> ResponseWriter::putOnWire(const char *data,
     auto fd = peer()->fd();
 
     return transport_->asyncWrite(fd, buffer)
-        .then<std::function<Async::Promise<ssize_t>(int)>,
+        .then<std::function<Async::Promise<ssize_t>(ssize_t)>,
               std::function<void(std::exception_ptr &)>>(
             [=](int /*l*/) {
               return Async::Promise<ssize_t>([=](

I don't know if it's a correct one though.

[miketsts]

The change below fixes the warning happening in date.h. I've checked the latest version of date.h in the source location - they suppress the warning the similar way, only locally in the file itself.

diff --git a/src/common/http_defs.cc b/src/common/http_defs.cc
index 31e3e76..30019cd 100644
--- a/src/common/http_defs.cc
+++ b/src/common/http_defs.cc
@@ -8,7 +8,14 @@
 #include <iostream>
 
 #include <pistache/common.h>
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wconversion"
+#endif
 #include <pistache/date.h>
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
 #include <pistache/http_defs.h>
 
 namespace Pistache {

[dennisjenkins75]

This PR breaks all travis builds. For example: https://travis-ci.org/github/oktal/pistache/jobs/674003067