Handle nested brace inside variable

Change-Id: I1004ea869bfe56b380109c7bcae866931b4d4725

jenkins_jobs/formatter.py

@@ -77,7 +77,7 @@ class CustomFormatter(Formatter):
 
         try:
             return super().vformat(format_string, args, kwargs)
-        except (JenkinsJobsException, UndefinedError) as x:
+        except (JenkinsJobsException, UndefinedError, ValueError) as x:
             if len(format_string) > 40:
                 short_fmt = format_string[:80] + "..."
             else:

tests/yamlparser/error_fixtures/nested_brace_in_variable.error

@@ -0,0 +1,9 @@
+nested_brace_in_variable.yaml:10:3: In project 'sample-project'
+    - project:
+      ^
+nested_brace_in_variable.yaml:5:3: In job template 'sample-job'
+    - job-template:
+      ^
+nested_brace_in_variable.yaml:8:15: While formatting string '{ {x} }': unexpected '{' in field name
+        - shell: '{ {x} }'
+                  ^

tests/yamlparser/error_fixtures/nested_brace_in_variable.yaml

@@ -0,0 +1,13 @@
+# Check braces inside variable does not cause parser to fail.
+# This may happen when tag !include-raw: is used instead of !include-raw-escape:
+# and there are nested blocks of groovy code inside included file.
+
+- job-template:
+    name: sample-job
+    builders:
+    - shell: '{ {x} }'
+
+- project:
+    name: sample-project
+    jobs:
+      - sample-job