Add Kconfig.__init__() helper flag for suppressing tracebacks

Tools that don't use standard_kconfig() currently generate spammy
tracebacks for e.g. syntax errors.

Add a suppress_traceback flag to Kconfig.__init__() for catching
"expected" exceptions and printing them to stderr and exiting with
status 1. Use it to make all tools consistently hide tracebacks.

6 files changed, 31 insertions, 15 deletions

diff --git a/defconfig.py b/defconfig.py
index d1b1e4e..173fc7b 100755
--- a/defconfig.py
+++ b/defconfig.py
@@ -34,7 +34,7 @@ def main():
 
     args = parser.parse_args()
 
-    kconf = kconfiglib.Kconfig(args.kconfig)
+    kconf = kconfiglib.Kconfig(args.kconfig, suppress_traceback=True)
     print(kconf.load_config(args.config))
     print(kconf.write_config())
 
diff --git a/examples/merge_config.py b/examples/merge_config.py
index 528e86c..2681b63 100755
--- a/examples/merge_config.py
+++ b/examples/merge_config.py
@@ -79,7 +79,7 @@ from kconfiglib import Kconfig, BOOL, TRISTATE, TRI_TO_STR
 if len(sys.argv) < 4:
     sys.exit("usage: merge_config.py Kconfig merged_config config1 [config2 ...]")
 
-kconf = Kconfig(sys.argv[1])
+kconf = Kconfig(sys.argv[1], suppress_traceback=True)
 
 # Enable warnings for assignments to undefined symbols
 kconf.warn_assign_undef = True
diff --git a/genconfig.py b/genconfig.py
index 7d701ff..3482673 100755
--- a/genconfig.py
+++ b/genconfig.py
@@ -109,7 +109,7 @@ only supported for backwards compatibility).
     args = parser.parse_args()
 
 
-    kconf = kconfiglib.Kconfig(args.kconfig_filename)
+    kconf = kconfiglib.Kconfig(args.kconfig_filename, suppress_traceback=True)
     kconf.load_config()
 
     if args.header_path is None:
diff --git a/kconfiglib.py b/kconfiglib.py
index 6199e8b..d152b76 100644
--- a/kconfiglib.py
+++ b/kconfiglib.py
@@ -865,7 +865,7 @@ class Kconfig(object):
     #
 
     def __init__(self, filename="Kconfig", warn=True, warn_to_stderr=True,
-                 encoding="utf-8"):
+                 encoding="utf-8", suppress_traceback=False):
         """
         Creates a new Kconfig object by parsing Kconfig files.
         Note that Kconfig files are not the same as .config files (which store
@@ -930,7 +930,31 @@ class Kconfig(object):
           anyway.
 
           Related PEP: https://www.python.org/dev/peps/pep-0538/
+
+        suppress_traceback (default: False):
+          Helper for tools. When True, any EnvironmentError or KconfigError
+          generated during parsing is caught, the exception message is printed
+          to stderr, and sys.exit(1) is called (which generates SystemExit).
+
+          This hides the Python traceback for "expected" errors like syntax
+          errors in Kconfig files.
+
+          Other exceptions besides EnvironmentError and KconfigError are still
+          propagated when suppress_traceback is True.
         """
+        try:
+            return self._init(filename, warn, warn_to_stderr, encoding)
+        except (EnvironmentError, KconfigError) as e:
+            if suppress_traceback:
+                # Some long exception messages have extra newlines for better
+                # formatting when reported as an unhandled exception. Strip
+                # them here.
+                sys.exit(str(e).strip())
+            raise
+
+    def _init(self, filename, warn, warn_to_stderr, encoding):
+        # See __init__()
+
         self._encoding = encoding
 
         self.srctree = os.getenv("srctree", "")
@@ -6182,15 +6206,7 @@ def standard_kconfig(description=None):
         nargs="?",
         help="Kconfig file (default: Kconfig)")
 
-    args = parser.parse_args()
-
-    # Suppress backtraces for expected exceptions
-    try:
-        return Kconfig(args.kconfig)
-    except (EnvironmentError, KconfigError) as e:
-        # Some long exception messages have extra newlines for better
-        # formatting when reported as an unhandled exception. Strip them here.
-        sys.exit(str(e).strip())
+    return Kconfig(parser.parse_args().kconfig, suppress_traceback=True)
 
 
 def standard_config_filename():
diff --git a/savedefconfig.py b/savedefconfig.py
index c388f1a..50850fa 100755
--- a/savedefconfig.py
+++ b/savedefconfig.py
@@ -40,7 +40,7 @@ def main():
 
     args = parser.parse_args()
 
-    kconf = kconfiglib.Kconfig(args.kconfig)
+    kconf = kconfiglib.Kconfig(args.kconfig, suppress_traceback=True)
     print(kconf.load_config())
     print(kconf.write_min_config(args.out))
 
diff --git a/setconfig.py b/setconfig.py
index b689754..4e5c409 100755
--- a/setconfig.py
+++ b/setconfig.py
@@ -59,7 +59,7 @@ def main():
 
     args = parser.parse_args()
 
-    kconf = kconfiglib.Kconfig(args.kconfig)
+    kconf = kconfiglib.Kconfig(args.kconfig, suppress_traceback=True)
     print(kconf.load_config())
 
     for arg in args.assignments: