Adding upstream version 0.13.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

examples/my_line_rules.py

@@ -0,0 +1,45 @@
+from gitlint.rules import LineRule, RuleViolation, CommitMessageTitle
+from gitlint.options import ListOption
+
+"""
+The SpecialChars class below is an example of a user-defined LineRule. Line rules are gitlint rules that only act on a
+single line at once. Once the rule is discovered, gitlint will automatically take care of applying this rule
+against each line of the commit message title or body (whether it is applied to the title or body is determined by the
+`target` attribute of the class).
+
+A LineRule contrasts with a CommitRule (see examples/my_commit_rules.py) in that a commit rule is only applied once on
+an entire commit. This allows commit rules to implement more complex checks that span multiple lines and/or checks
+that should only be done once per gitlint run.
+
+While every LineRule can be implemented as a CommitRule, it's usually easier and more concise to go with a LineRule if
+that fits your needs.
+"""
+
+
+class SpecialChars(LineRule):
+    """ This rule will enforce that the commit message title does not contain any of the following characters:
+        $^%@!*() """
+
+    # A rule MUST have a human friendly name
+    name = "title-no-special-chars"
+
+    # A rule MUST have a *unique* id, we recommend starting with UL (for User-defined Line-rule), but this can
+    # really be anything.
+    id = "UL1"
+
+    # A line-rule MUST have a target (not required for CommitRules).
+    target = CommitMessageTitle
+
+    # A rule MAY have an option_spec if its behavior should be configurable.
+    options_spec = [ListOption('special-chars', ['$', '^', '%', '@', '!', '*', '(', ')'],
+                               "Comma separated list of characters that should not occur in the title")]
+
+    def validate(self, line, _commit):
+        violations = []
+        # options can be accessed by looking them up by their name in self.options
+        for char in self.options['special-chars'].value:
+            if char in line:
+                violation = RuleViolation(self.id, "Title contains the special character '{0}'".format(char), line)
+                violations.append(violation)
+
+        return violations