lib/bb/data_smart.py: don't report variable in ExpansionError if not set

If the variable name is not specified then don't confuse the error message
by starting off with "Failure expanding variable None...".

(Bitbake rev: 9cb16f3c73751e7cf6d495586a6193f06eb97b1f)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/bitbake/lib/bb/data_smart.py b/bitbake/lib/bb/data_smart.py
index 27fb7d9915..2c02cdeabf 100644
--- a/bitbake/lib/bb/data_smart.py
+++ b/bitbake/lib/bb/data_smart.py
@@ -102,7 +102,10 @@ class ExpansionError(Exception):
         self.expression = expression
         self.variablename = varname
         self.exception = exception
-        self.msg = "Failure expanding variable %s, expression was %s which triggered exception %s: %s" % (varname, expression, type(exception).__name__, exception)
+        if varname:
+            self.msg = "Failure expanding variable %s, expression was %s which triggered exception %s: %s" % (varname, expression, type(exception).__name__, exception)
+        else:
+            self.msg = "Failure expanding expression %s which triggered exception %s: %s" % (expression, type(exception).__name__, exception)
         Exception.__init__(self, self.msg)
         self.args = (varname, expression, exception)
     def __str__(self):