Get Windows tests working & passing. (#560)

I added an appveyor.yml. This should mean I no longer have to configure appveyor in the web UI. And more of the test is set up automatically, without awkward scripting in various convoluted languages.

But it also gave me the opportunity to get the tests running on Windows. And guess what? They didn't all pass! The test for asynchronous connection (using pqxx::connecting) would hang. Turns out it was completely unnecessary for libpqxx to manage blocking/nonblocking mode on the socket. So that's fixed now.

NEWS

@@ -7,6 +7,8 @@
  - Deprecate `exec` functions' `desc` parameter.
  - Fix `placeholders` documentation.  (#557)
  - Strip `const` and references from `value_type`. (#558)
+ - Get tests running on appveyor. (#560)
+ - Fix broken nonblocking connection on Windows. (#560)
 7.7.2
  - Fix up damage done by auto-formatting.
 7.7.1

appveyor.yml

@@ -0,0 +1,28 @@
+version: 1.0.{build}
+image: Visual Studio 2022
+services: postgresql12
+before_build:
+- cmd: >-
+    call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"
+
+    cmake -DBUILD_SHARED_LIBS=1 -DCMAKE_CXX_STANDARD=23
+configuration: Release
+build:
+  parallel: true
+  project: libpqxx.sln
+test_script:
+- ps: >-
+    $env:Path += ";.\src\Release;C:\Program Files\PostgreSQL\12\bin"
+
+    $env:PGUSER = "postgres"
+
+    $env:PGPASSWORD = "Password12!"
+
+    .\test\Release\runner.exe
+notifications:
+- provider: Email
+  subject: 'libpqxx: AppVeyor build failure'
+  message: The libpqxx AppVeyor build has failed.
+  on_build_success: false
+  on_build_failure: true
+  on_build_status_changed: false

include/pqxx/connection.hxx

@@ -905,6 +905,10 @@ public:
 
 #if defined(_WIN32) || __has_include(<fcntl.h>)
   /// Set socket to blocking (true) or nonblocking (false).
+  /** @warning Do not use this unless you _really_ know what you're doing.
+   * @warning This function is available on most systems, but not necessarily
+   * all.
+   */
   void set_blocking(bool block) &;
 #endif // defined(_WIN32) || __has_include(<fcntl.h>)
 

src/connection.cxx

@@ -100,6 +100,8 @@ pqxx::connection::connection(
 {
   if (m_conn == nullptr)
     throw std::bad_alloc{};
+  if (status() == CONNECTION_BAD)
+    throw pqxx::broken_connection{PQerrorMessage(m_conn)};
 }
 
 
@@ -138,6 +140,7 @@ void pqxx::connection::complete_init()
   catch (std::exception const &)
   {
     PQfinish(m_conn);
+    m_conn = nullptr;
     throw;
   }
 }
@@ -479,6 +482,7 @@ void PQXX_COLD pqxx::connection::cancel_query()
 
 namespace
 {
+// C++20: std::span?
 /// Get error string for a given @c errno value.
 template<std::size_t BYTES>
 char const *PQXX_COLD
@@ -1245,7 +1249,6 @@ std::string pqxx::connection::connection_string() const
 pqxx::connecting::connecting(zview connection_string) :
         m_conn{connection::connect_nonblocking, connection_string}
 {
-  m_conn.set_blocking(false);
 }
 #endif // defined(_WIN32) || __has_include(<fcntl.h>
 
@@ -1266,7 +1269,6 @@ pqxx::connection pqxx::connecting::produce() &&
   if (!done())
     throw usage_error{
       "Tried to produce a nonblocking connection before it was done."};
-  m_conn.set_blocking(true);
   m_conn.complete_init();
   return std::move(m_conn);
 }

src/wait.cxx

@@ -90,7 +90,7 @@ void pqxx::internal::wait_fd(
   short const events{static_cast<short>(
     (for_read ? POLLRDNORM : 0) | (for_write ? POLLWRNORM : 0))};
   WSAPOLLFD fdarray{SOCKET(fd), events, 0};
-  WSAPoll(&fdarray, 1, to_milli<unsigned>(seconds, microseconds));
+  WSAPoll(&fdarray, 1u, to_milli<unsigned>(seconds, microseconds));
   // TODO: Check for errors.
 #elif defined(PQXX_HAVE_POLL)
   auto const events{static_cast<short>(

test/unit/test_nonblocking_connect.cxx

@@ -1,4 +1,3 @@
-#include <pqxx/connection>
 #include <pqxx/transaction>
 
 #include <pqxx/internal/wait.hxx>