cmake: Better error message when configuring a CMake subproject fails.

2 files changed, 23 insertions, 4 deletions

diff --git a/mesonbuild/cmake/interpreter.py b/mesonbuild/cmake/interpreter.py
index 3f9326a..bbb0ce4 100644
--- a/mesonbuild/cmake/interpreter.py
+++ b/mesonbuild/cmake/interpreter.py
@@ -777,7 +777,7 @@ class CMakeInterpreter:
         # Raw CMake results
         self.bs_files          = []    # type: T.List[Path]
         self.codemodel_configs = None  # type: T.Optional[T.List[CMakeConfiguration]]
-        self.raw_trace         = None  # type: T.Optional[str]
+        self.cmake_stderr      = None  # type: T.Optional[str]
 
         # Analysed data
         self.project_name      = ''
@@ -841,13 +841,17 @@ class CMakeInterpreter:
             final_args = cmake_args + trace_args + cmcmp_args + toolchain.get_cmake_args() + [self.src_dir.as_posix()]
 
             cmake_exe.set_exec_mode(print_cmout=True, always_capture_stderr=self.trace.requires_stderr())
-            rc, _, self.raw_trace = cmake_exe.call(final_args, self.build_dir, env=os_env, disable_cache=True)
+            rc, _, self.cmake_stderr = cmake_exe.call(final_args, self.build_dir, env=os_env, disable_cache=True)
 
         mlog.log()
         h = mlog.green('SUCCEEDED') if rc == 0 else mlog.red('FAILED')
         mlog.log('CMake configuration:', h)
         if rc != 0:
-            raise CMakeException('Failed to configure the CMake subproject')
+            # get the last CMake error - We only need the message function for this:
+            self.trace.functions = {'message': self.trace.functions['message']}
+            self.trace.parse(self.cmake_stderr)
+            error = f': {self.trace.errors[-1]}' if self.trace.errors else ''
+            raise CMakeException(f'Failed to configure the CMake subproject{error}')
 
         return cmake_exe
 
@@ -879,7 +883,7 @@ class CMakeInterpreter:
         self.custom_targets = []
 
         # Parse the trace
-        self.trace.parse(self.raw_trace)
+        self.trace.parse(self.cmake_stderr)
 
         # Find all targets
         added_target_names = []  # type: T.List[str]
diff --git a/mesonbuild/cmake/traceparser.py b/mesonbuild/cmake/traceparser.py
index 7336d15..967b40a 100644
--- a/mesonbuild/cmake/traceparser.py
+++ b/mesonbuild/cmake/traceparser.py
@@ -111,6 +111,8 @@ class CMakeTraceParser:
         self.trace_file_path = build_dir / self.trace_file
         self.trace_format = 'json-v1' if version_compare(cmake_version, '>=3.17') else 'human'
 
+        self.errors: T.List[str] = []
+
         # State for delayed command execution. Delayed command execution is realised
         # with a custom CMake file that overrides some functions and adds some
         # introspection information to the trace.
@@ -133,6 +135,7 @@ class CMakeTraceParser:
             'target_link_libraries': self._cmake_target_link_libraries,
             'target_link_options': self._cmake_target_link_options,
             'add_dependencies': self._cmake_add_dependencies,
+            'message': self._cmake_message,
 
             # Special functions defined in the preload script.
             # These functions do nothing in the CMake code, but have special
@@ -639,6 +642,18 @@ class CMakeTraceParser:
         # DOC: https://cmake.org/cmake/help/latest/command/target_link_libraries.html
         self._parse_common_target_options('target_link_options', 'LINK_LIBRARIES', 'INTERFACE_LINK_LIBRARIES', tline)
 
+    def _cmake_message(self, tline: CMakeTraceLine) -> None:
+        # DOC: https://cmake.org/cmake/help/latest/command/message.html
+        args = list(tline.args)
+
+        if len(args) < 1:
+            return self._gen_exception('message', 'takes at least 1 argument', tline)
+
+        if args[0].upper().strip() not in ['FATAL_ERROR', 'SEND_ERROR']:
+            return
+
+        self.errors += [' '.join(args[1:])]
+
     def _parse_common_target_options(self, func: str, private_prop: str, interface_prop: str, tline: CMakeTraceLine, ignore: T.Optional[T.List[str]] = None, paths: bool = False) -> None:
         if ignore is None:
             ignore = ['BEFORE']