compilers: Use a distinct type for compile/link results

Currently we do some crazy hackery where we add extra properties to a
Popen object and return that. That's crazy. Especially since some of our
hackery is to delete attributes off of the Popen we don't want. Instead,
let's just have a discrete type that has exactly the properties we want.

5 files changed, 42 insertions, 29 deletions

diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index c4bd7c2..dc6dd5c 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -405,6 +405,29 @@ class RunResult:
         self.stderr = stderr
 
 
+class CompileResult:
+
+    """The result of Compiler.compiles (and friends)."""
+
+    def __init__(self, stdo: T.Optional[str] = None, stde: T.Optional[str] = None,
+                 args: T.Optional[T.List[str]] = None,
+                 returncode: int = 999, pid: int = -1,
+                 text_mode: bool = True,
+                 input_name: T.Optional[str] = None,
+                 output_name: T.Optional[str] = None,
+                 command: T.Optional[T.List[str]] = None, cached: bool = False):
+        self.stdout = stdo
+        self.stderr = stde
+        self.input_name = input_name
+        self.output_name = output_name
+        self.command = command or []
+        self.args = args or []
+        self.cached = cached
+        self.returncode = returncode
+        self.pid = pid
+        self.text_mode = text_mode
+
+
 class Compiler(metaclass=abc.ABCMeta):
     # Libraries to ignore in find_library() since they are provided by the
     # compiler or the C library. Currently only used for MSVC.
@@ -633,7 +656,7 @@ class Compiler(metaclass=abc.ABCMeta):
         return CompilerArgs(self, args)
 
     @contextlib.contextmanager
-    def compile(self, code: str, extra_args: list = None, *, mode: str = 'link', want_output: bool = False, temp_dir: str = None):
+    def compile(self, code: str, extra_args: list = None, *, mode: str = 'link', want_output: bool = False, temp_dir: str = None) -> T.Iterator[CompileResult]:
         if extra_args is None:
             extra_args = []
         try:
@@ -671,15 +694,14 @@ class Compiler(metaclass=abc.ABCMeta):
                 os_env['LC_ALL'] = 'C'
                 if no_ccache:
                     os_env['CCACHE_DISABLE'] = '1'
-                p, p.stdo, p.stde = Popen_safe(commands, cwd=tmpdirname, env=os_env)
-                mlog.debug('Compiler stdout:\n', p.stdo)
-                mlog.debug('Compiler stderr:\n', p.stde)
-                p.commands = commands
-                p.input_name = srcname
+                p, stdo, stde = Popen_safe(commands, cwd=tmpdirname, env=os_env)
+                mlog.debug('Compiler stdout:\n', stdo)
+                mlog.debug('Compiler stderr:\n', stde)
+
+                result = CompileResult(stdo, stde, list(commands), p.returncode, p.pid, input_name=srcname)
                 if want_output:
-                    p.output_name = output
-                p.cached = False  # Make sure that the cached attribute always exists
-                yield p
+                    result.output_name = output
+                yield result
         except OSError:
             # On Windows antivirus programs and the like hold on to files so
             # they can't be deleted. There's not much to do in this case. Also,
@@ -687,7 +709,7 @@ class Compiler(metaclass=abc.ABCMeta):
             pass
 
     @contextlib.contextmanager
-    def cached_compile(self, code, cdata: coredata.CoreData, *, extra_args=None, mode: str = 'link', temp_dir=None):
+    def cached_compile(self, code, cdata: coredata.CoreData, *, extra_args=None, mode: str = 'link', temp_dir=None) -> T.Iterator[CompileResult]:
         assert(isinstance(cdata, coredata.CoreData))
 
         # Calculate the key
@@ -697,21 +719,13 @@ class Compiler(metaclass=abc.ABCMeta):
         # Check if not cached
         if key not in cdata.compiler_check_cache:
             with self.compile(code, extra_args=extra_args, mode=mode, want_output=False, temp_dir=temp_dir) as p:
-                # Remove all attributes except the following
-                # This way the object can be serialized
-                tokeep = ['args', 'commands', 'input_name', 'output_name',
-                          'pid', 'returncode', 'stdo', 'stde', 'text_mode']
-                todel = [x for x in vars(p).keys() if x not in tokeep]
-                for i in todel:
-                    delattr(p, i)
-                p.cached = False
                 cdata.compiler_check_cache[key] = p
                 yield p
+                p.cached = True
                 return
 
         # Return cached
         p = cdata.compiler_check_cache[key]
-        p.cached = True
         mlog.debug('Using cached compile:')
         mlog.debug('Cached command line: ', ' '.join(p.commands), '\n')
         mlog.debug('Code:\n', code)
diff --git a/mesonbuild/compilers/mixins/clike.py b/mesonbuild/compilers/mixins/clike.py
index b2942d3..6a069b6 100644
--- a/mesonbuild/compilers/mixins/clike.py
+++ b/mesonbuild/compilers/mixins/clike.py
@@ -446,7 +446,7 @@ class CLikeCompiler:
         with self._build_wrapper(code, env, extra_args, dependencies, mode, disable_cache=disable_cache) as p:
             return p.returncode == 0, p.cached
 
-    def _build_wrapper(self, code: str, env, extra_args, dependencies=None, mode: str = 'compile', want_output: bool = False, disable_cache: bool = False, temp_dir: str = None) -> T.Tuple[bool, bool]:
+    def _build_wrapper(self, code: str, env, extra_args, dependencies=None, mode: str = 'compile', want_output: bool = False, disable_cache: bool = False, temp_dir: str = None) -> T.Iterator[compilers.CompileResult]:
         args = self._get_compiler_check_args(env, extra_args, dependencies, mode)
         if disable_cache or want_output:
             return self.compile(code, extra_args=args, mode=mode, want_output=want_output, temp_dir=env.scratch_dir)
@@ -665,7 +665,7 @@ class CLikeCompiler:
         # Get the preprocessed value after the delimiter,
         # minus the extra newline at the end and
         # merge string literals.
-        return self.concatenate_string_literals(p.stdo.split(delim + '\n')[-1][:-1]), cached
+        return self.concatenate_string_literals(p.stdout.split(delim + '\n')[-1][:-1]), cached
 
     def get_return_value(self, fname, rtype, prefix, env, extra_args, dependencies):
         if rtype == 'string':
@@ -889,7 +889,7 @@ class CLikeCompiler:
         with self._build_wrapper(code, env, extra_args=args, mode='compile', want_output=True, temp_dir=env.scratch_dir) as p:
             if p.returncode != 0:
                 m = 'BUG: Unable to compile {!r} check: {}'
-                raise RuntimeError(m.format(n, p.stdo))
+                raise RuntimeError(m.format(n, p.stdout))
             if not os.path.isfile(p.output_name):
                 m = 'BUG: Can\'t find compiled test code for {!r} check'
                 raise RuntimeError(m.format(n))
diff --git a/mesonbuild/compilers/mixins/gnu.py b/mesonbuild/compilers/mixins/gnu.py
index 83f7047..538cc03 100644
--- a/mesonbuild/compilers/mixins/gnu.py
+++ b/mesonbuild/compilers/mixins/gnu.py
@@ -227,8 +227,7 @@ class GnuLikeCompiler(metaclass=abc.ABCMeta):
         with self._build_wrapper('', env, extra_args=extra_args,
                                  dependencies=None, mode='compile',
                                  want_output=True) as p:
-            stdo = p.stdo
-        return stdo
+            return p.stdout
 
     def _split_fetch_real_dirs(self, pathstr: str) -> T.List[str]:
         # We need to use the path separator used by the compiler for printing
@@ -364,9 +363,9 @@ class GnuCompiler(GnuLikeCompiler):
         # another language, but still complete with exit_success
         with self._build_wrapper(code, env, args, None, mode) as p:
             result = p.returncode == 0
-            if self.language in {'cpp', 'objcpp'} and 'is valid for C/ObjC' in p.stde:
+            if self.language in {'cpp', 'objcpp'} and 'is valid for C/ObjC' in p.stderr:
                 result = False
-            if self.language in {'c', 'objc'} and 'is valid for C++/ObjC++' in p.stde:
+            if self.language in {'c', 'objc'} and 'is valid for C++/ObjC++' in p.stderr:
                 result = False
         return result, p.cached
 
diff --git a/mesonbuild/compilers/mixins/visualstudio.py b/mesonbuild/compilers/mixins/visualstudio.py
index 0ea03f0..74229e3 100644
--- a/mesonbuild/compilers/mixins/visualstudio.py
+++ b/mesonbuild/compilers/mixins/visualstudio.py
@@ -296,7 +296,7 @@ class VisualStudioLikeCompiler(metaclass=abc.ABCMeta):
         with self._build_wrapper(code, env, extra_args=args, mode=mode) as p:
             if p.returncode != 0:
                 return False, p.cached
-            return not(warning_text in p.stde or warning_text in p.stdo), p.cached
+            return not(warning_text in p.stderr or warning_text in p.stdout), p.cached
 
     def get_compile_debugfile_args(self, rel_obj: str, pch: bool = False) -> T.List[str]:
         pdbarr = rel_obj.split('.')[:-1]
diff --git a/mesonbuild/coredata.py b/mesonbuild/coredata.py
index a36bbe9..baae32b 100644
--- a/mesonbuild/coredata.py
+++ b/mesonbuild/coredata.py
@@ -32,7 +32,7 @@ import typing as T
 
 if T.TYPE_CHECKING:
     from . import dependencies
-    from .compilers import Compiler  # noqa: F401
+    from .compilers import Compiler, CompileResult  # noqa: F401
     from .environment import Environment
 
     OptionDictType = T.Dict[str, 'UserOption[T.Any]']
@@ -394,7 +394,7 @@ class CoreData:
         build_cache = DependencyCache(self.builtins_per_machine, MachineChoice.BUILD)
         host_cache = DependencyCache(self.builtins_per_machine, MachineChoice.BUILD)
         self.deps = PerMachine(build_cache, host_cache)  # type: PerMachine[DependencyCache]
-        self.compiler_check_cache = OrderedDict()
+        self.compiler_check_cache = OrderedDict()  # type: T.MutableMapping[T.Tuple[T.Tuple[str, ...], str, str, T.Tuple[str, ...], str], CompileResult]
 
         # Only to print a warning if it changes between Meson invocations.
         self.config_files = self.__load_config_files(options, scratch_dir, 'native')