Adding option to print full error information for HPX exceptions

- add PHYLANX_WITH_PYTHON_TESTS_EMIT_FULL_DIAGNOSTICS cmake variable
- enable this option for CircleCI
- adding ability to add to the Phylanx session configuration through
  PHYLANX_PYTHON_CONFIG environment variable

- adding --hpx:ini=phylanx.full_error_diagnostics!=1 to enable full
  error diagnostics from Python code

.circleci/config.yml

@@ -153,7 +153,8 @@ jobs:
                         -DPHYLANX_WITH_ITERATIVE_SOLVERS=ON         \
                         -DPHYLANX_WITH_DOCUMENTATION=ON             \
                         -DPHYLANX_WITH_HIGHFIVE=OFF                 \
-                        -DPHYLANX_WITH_CXX17=ON
+                        -DPHYLANX_WITH_CXX17=ON                     \
+                        -DPHYLANX_WITH_PYTHON_TESTS_EMIT_FULL_DIAGNOSTICS=On
             - persist_to_workspace:
                 root: /
                 paths:

CMakeLists.txt

@@ -95,6 +95,11 @@ phylanx_option(
   "Enable or disable the compilation of benchmark tests"
   ON ADVANCED CATEGORY "Build")
 
+phylanx_option(
+  PHYLANX_WITH_PYTHON_TESTS_EMIT_FULL_DIAGNOSTICS BOOL
+  "Python tests emit the full HPX diagnostics if exceptions are thrown"
+  OFF ADVANCED CATEGORY "Build")
+
 phylanx_option(
   PHYLANX_WITH_TESTS_REGRESSIONS BOOL
   "Enable or disable the compilation of regression tests"

cmake/Phylanx_AddPythonTest.cmake

@@ -30,11 +30,16 @@ macro(add_phylanx_python_test category name)
   phylanx_debug("add_phylanx_python_test (${name})" "WORKING_DIRECTORY: ${_working_directory}")
 
   set(_environment)
+  if(PHYLANX_WITH_PYTHON_TESTS_EMIT_FULL_DIAGNOSTICS)
+    set(_environment
+      PHYLANX_PYTHON_CONFIG="--hpx:ini=phylanx.full_error_diagnostics!=1"
+    )
+  endif()
   if(${name}_ENVIRONMENT)
     if(MSVC)
-      set(_environment ${CMAKE_COMMAND} -E env "${${name}_ENVIRONMENT}")
+      set(_environment ${CMAKE_COMMAND} -E env ${_environment} ${${name}_ENVIRONMENT})
     else()
-      set(_environment ENVIRONMENT "${${name}_ENVIRONMENT}")
+      set(_environment ENVIRONMENT ${_environment} ${${name}_ENVIRONMENT})
     endif()
   endif()
   phylanx_debug("add_phylanx_python_test (${name})" "ENVIRONMENT: ${_environment}")

python/phylanx/core/config.py

@@ -6,6 +6,9 @@
 from phylanx.core import init_hpx_runtime
 from phylanx.exceptions import RuntimeAlreadyInitializedError
 
+import os
+import platform
+
 
 class PhylanxSession:
     cfg = [
@@ -30,6 +33,17 @@ def init(num_threads=1):
         if not PhylanxSession.is_initialized:
             hpx_thread = "hpx.os_threads!=%s" % num_threads
             PhylanxSession.cfg[3] = hpx_thread
+
+            # append additional config settings taken from the environment
+            if 'PHYLANX_PYTHON_CONFIG' in os.environ:
+                if platform.system() == "Windows":
+                    sep = ';'
+                else:
+                    sep = ':'
+
+                for e in os.environ['PHYLANX_PYTHON_CONFIG'].split(sep):
+                    PhylanxSession.cfg.append(e)
+
             init_hpx_runtime(PhylanxSession.cfg)
             PhylanxSession.is_initialized = True
         else:

python/src/bindings/execution_tree.cpp

@@ -18,6 +18,7 @@
 #include <hpx/runtime/threads/run_as_hpx_thread.hpp>
 
 #include <cstdint>
+#include <exception>
 #include <string>
 #include <vector>
 #include <utility>
@@ -307,4 +308,28 @@ void phylanx::bindings::bind_execution_tree(pybind11::module m)
                     });
             },
             "wait for future to become ready");
+
+    // translate HPX exceptions and provide more error information, if desired
+    static pybind11::exception<hpx::exception> exc(
+        m, "HPXError", PyExc_RuntimeError);
+
+    pybind11::register_exception_translator([](std::exception_ptr p) {
+        try
+        {
+            if (p)
+                std::rethrow_exception(p);
+        }
+        catch (hpx::exception& e)
+        {
+            if (hpx::get_config_entry("phylanx.full_error_diagnostics", "0") ==
+                "1")
+            {
+                exc(hpx::diagnostic_information(e).c_str());
+            }
+            else
+            {
+                exc(e.what());
+            }
+        }
+    });
 }