Bug 807974 - Handle make errors more gracefully; r=jhammel

We now return the status code from executed processes. The API to
require a successful status code has been changed from ignore_errors to
ensure_exit_code. The build mach command no longer spews a stack trace
if make fails.

DONTBUILD (NPOTB)

python/mach/mach/mixin/process.py

@@ -43,7 +43,7 @@ class ProcessExecutionMixin(LoggingMixin):
     def run_process(self, args=None, cwd=None, append_env=None,
         explicit_env=None, log_name=None, log_level=logging.INFO,
         line_handler=None, require_unix_environment=False,
-        ignore_errors=False, ignore_children=False):
+        ensure_exit_code=0, ignore_children=False):
         """Runs a single process to completion.
 
         Takes a list of arguments to run where the first item is the
@@ -60,6 +60,11 @@ class ProcessExecutionMixin(LoggingMixin):
         execute the command via an appropriate UNIX-like shell.
 
         ignore_children is proxied to mozprocess's ignore_children.
+
+        ensure_exit_code is used to ensure the exit code of a process matches
+        what is expected. If it is an integer, we raise an Exception is the
+        exit code does not match this value. If it is True, we ensure the exit
+        code is 0. If it is False, we don't perform any exit code validation.
         """
         args = self._normalize_command(args, require_unix_environment)
 
@@ -96,9 +101,17 @@ class ProcessExecutionMixin(LoggingMixin):
         p.processOutput()
         status = p.wait()
 
-        if status != 0 and not ignore_errors:
+        if ensure_exit_code is False:
+            return status
+
+        if ensure_exit_code is True:
+            ensure_exit_code = 0
+
+        if status != ensure_exit_code:
             raise Exception('Process executed with non-0 exit code: %s' % args)
 
+        return status
+
     def _normalize_command(self, args, require_unix_environment):
         """Adjust command arguments to run in the necessary environment.
 

python/mozbuild/mozbuild/base.py

@@ -168,7 +168,7 @@ class MozbuildObject(ProcessExecutionMixin):
     def _run_make(self, directory=None, filename=None, target=None, log=True,
             srcdir=False, allow_parallel=True, line_handler=None,
             append_env=None, explicit_env=None, ignore_errors=False,
-            silent=True, print_directory=True):
+            ensure_exit_code=0, silent=True, print_directory=True):
         """Invoke make.
 
         directory -- Relative directory to look for Makefile in.
@@ -224,7 +224,7 @@ class MozbuildObject(ProcessExecutionMixin):
             'explicit_env': explicit_env,
             'log_level': logging.INFO,
             'require_unix_environment': True,
-            'ignore_errors': ignore_errors,
+            'ensure_exit_code': ensure_exit_code,
 
             # Make manages its children, so mozprocess doesn't need to bother.
             # Having mozprocess manage children can also have side-effects when
@@ -235,7 +235,7 @@ class MozbuildObject(ProcessExecutionMixin):
         if log:
             params['log_name'] = 'make'
 
-        fn(**params)
+        return fn(**params)
 
     @property
     def _make_path(self):
@@ -258,10 +258,10 @@ class MozbuildObject(ProcessExecutionMixin):
         return self._make
 
     def _run_command_in_srcdir(self, **args):
-        self.run_process(cwd=self.topsrcdir, **args)
+        return self.run_process(cwd=self.topsrcdir, **args)
 
     def _run_command_in_objdir(self, **args):
-        self.run_process(cwd=self.topobjdir, **args)
+        return self.run_process(cwd=self.topobjdir, **args)
 
     def _is_windows(self):
         return os.name in ('nt', 'ce')

python/mozbuild/mozbuild/mach_commands.py

@@ -49,8 +49,9 @@ class Build(MachCommandBase):
 
             self.log(logging.INFO, 'build_output', {'line': line}, '{line}')
 
-        self._run_make(srcdir=True, filename='client.mk', line_handler=on_line,
-            log=False, print_directory=False)
+        status = self._run_make(srcdir=True, filename='client.mk',
+            line_handler=on_line, log=False, print_directory=False,
+            ensure_exit_code=False)
 
         self.log(logging.WARNING, 'warning_summary',
             {'count': len(warnings_collector.database)},
@@ -58,6 +59,8 @@ class Build(MachCommandBase):
 
         warnings_database.save_to_file(warnings_path)
 
+        return status
+
 
 @CommandProvider
 class Warnings(MachCommandBase):