Use workflow commands to annotate linter errors

travis/lint.py

@@ -18,28 +18,13 @@ def valid_file(filename):
         not len(list(filter(lambda path: path.replace('\\', '/') in filename.replace('\\', '/'), path_blacklist)))
 
 success = True
-def error(msg):
+def error(msg=None):
     global success
     success = False
+    if msg:
         sys.stderr.write(msg + '\n')
 
-class LinterError(Exception): pass
-
-class Linter(object):
-    ignore = False
-    def check(self, lines):
-        failures = []
-        for i, line in enumerate(lines):
-            if not self.check_line(line):
-                failures.append(i + 1)
-        if len(failures):
-            raise LinterError('%s: %s' % (self.msg, self.display_lines(failures, len(lines))))
-
-    def fix(self, lines):
-        for i in range(len(lines)):
-            lines[i] = self.fix_line(lines[i])
-
-    def display_lines(self, lines, total):
+def format_lines(lines, total):
     if len(lines) == total - 1:
         return 'entire file'
     if not len(lines):
@@ -64,6 +49,34 @@ class Linter(object):
                 s += ('%i-%i, ' % (range_start, range_end))
     return s.rstrip(' ').rstrip(',')
 
+class LinterError(Exception):
+    def __init__(self, message, lines, total_lines):
+        self.message = message
+        self.lines = lines
+        self.total_lines = total_lines
+
+    def __str__(self):
+        return '%s: %s' % (self.message, format_lines(self.lines, self.total_lines))
+
+    def github_actions_workflow_command(self, filename):
+        first_line = self.lines[0] if self.lines else 1
+        return '::error file=%s,line=%i::%s' % (filename, first_line, self)
+
+class Linter(object):
+    ignore = False
+    def check(self, lines):
+        failures = []
+        for i, line in enumerate(lines):
+            if not self.check_line(line):
+                failures.append(i + 1)
+        if len(failures):
+            raise LinterError(self.msg, failures, len(lines))
+
+    def fix(self, lines):
+        for i in range(len(lines)):
+            lines[i] = self.fix_line(lines[i])
+
+
 class NewlineLinter(Linter):
     msg = 'Contains DOS-style newlines'
     # git supports newline conversion.  Catch in CI, ignore on Windows.
@@ -91,6 +104,7 @@ class TabLinter(Linter):
 linters = [cls() for cls in Linter.__subclasses__() if not cls.ignore]
 
 def main():
+    is_github_actions = os.environ.get('GITHUB_ACTIONS')
     root_path = os.path.abspath(sys.argv[1] if len(sys.argv) > 1 else '.')
     if not os.path.exists(root_path):
         print('Nonexistent path: %s' % root_path)
@@ -112,12 +126,21 @@ def main():
                     try:
                         lines[i] = line.decode('utf-8')
                     except UnicodeDecodeError:
-                        error('%s:%i: Invalid UTF-8 (other errors will be ignored)' % (rel_path, i + 1))
+                        msg_params = (rel_path, i + 1, 'Invalid UTF-8 (other errors will be ignored)')
+                        if is_github_actions:
+                            error()
+                            print('::error file=%s,line=%i::%s' % msg_params)
+                        else:
+                            error('%s:%i: %s' % msg_params)
                         lines[i] = ''
             for linter in linters:
                 try:
                     linter.check(lines)
                 except LinterError as e:
+                    if is_github_actions:
+                        error()
+                        print(e.github_actions_workflow_command(rel_path))
+                    else:
                         error('%s: %s' % (rel_path, e))
                     if fix:
                         linter.fix(lines)