set lint rules to avoid leading or trailing empty lines in frontmatter string values

Fix #2034
Ref #1997

tools/lint/lib/checks/nopadding.py

@@ -0,0 +1,21 @@
+from ..check import Check
+import re
+
+class CheckNoPadding(Check):
+    '''Ensure frontmatter string tags doesn't contain leading empty lines'''
+    ID = 'NOPADDING'
+
+    def __init__(self):
+        self.noPadding = re.compile(r"^(?![\r\n])[\s\S]*")
+
+    def run(self, name, meta, source):
+        if not meta:
+            return
+
+        if 'description' in meta:
+            if self.noPadding.match(meta['description']) == None:
+                return 'The `description` tag should not have leading empty lines'
+
+        if 'info' in meta:
+            if self.noPadding.match(meta['info']) == None:
+                return 'The `info` tag should not have leading empty lines'

tools/lint/lint.py

@@ -37,6 +37,7 @@ from lib.checks.harness import CheckHarness
 from lib.checks.license import CheckLicense
 from lib.checks.negative import CheckNegative
 from lib.checks.filename import CheckFileName
+from lib.checks.nopadding import CheckNoPadding
 from lib.eprint import eprint
 import lib.frontmatter
 import lib.exceptions
@@ -57,7 +58,8 @@ checks = [
     CheckHarnessFeatures(),
     CheckHarness(),
     CheckLicense(),
-    CheckNegative()
+    CheckNegative(),
+    CheckNoPadding()
 ]
 
 def lint(file_names):