fix : proper update of config file (before it was discarding architectures that were not the current one) fixes #774

3 files changed, 13 insertions, 12 deletions

diff --git a/bin/spack b/bin/spack
index 31165bba9d..f51cb8a4ec 100755
--- a/bin/spack
+++ b/bin/spack
@@ -152,7 +152,7 @@ def main():
     command = spack.cmd.get_command(args.command)
     try:
         return_val = command(parser, args)
-    except SpackError, e:
+    except SpackError as e:
         e.die()
     except KeyboardInterrupt:
         sys.stderr.write('\n')
diff --git a/lib/spack/spack/cmd/compiler.py b/lib/spack/spack/cmd/compiler.py
index 3e58e82184..786b3b8eb4 100644
--- a/lib/spack/spack/cmd/compiler.py
+++ b/lib/spack/spack/cmd/compiler.py
@@ -22,19 +22,18 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import sys
 import argparse
+import sys
 
 import llnl.util.tty as tty
-from llnl.util.tty.color import colorize
-from llnl.util.tty.colify import colify
-from llnl.util.lang import index_by
-
 import spack.compilers
-import spack.spec
 import spack.config
-from spack.util.environment import get_path
+import spack.spec
+from llnl.util.lang import index_by
+from llnl.util.tty.colify import colify
+from llnl.util.tty.color import colorize
 from spack.spec import CompilerSpec
+from spack.util.environment import get_path
 
 description = "Manage compilers"
 
diff --git a/lib/spack/spack/config.py b/lib/spack/spack/config.py
index 14e5aaf4fb..336d47cbb7 100644
--- a/lib/spack/spack/config.py
+++ b/lib/spack/spack/config.py
@@ -539,14 +539,16 @@ def update_config(section, update_data, scope=None):
        other yaml-ish structure.
 
     """
+    validate_section_name(section)  # validate section name
+    scope = validate_scope(scope)  # get ConfigScope object from string.
+
     # read in the config to ensure we've got current data
-    get_config(section)
+    configuration = get_config(section)
 
-    validate_section_name(section)       # validate section name
-    scope = validate_scope(scope)   # get ConfigScope object from string.
+    configuration.update(update_data)
 
     # read only the requested section's data.
-    scope.sections[section] = { section : update_data }
+    scope.sections[section] = {section: configuration}
     scope.write_section(section)