Bug 1652503: [mozlint] Use `attrs` for `mozlint.result.Issue`; r=ahal

This gives sorting on `Issue` for free, which makes it easier to write tests
for linters.

Differential Revision: https://phabricator.services.mozilla.com/D84643

python/mozlint/mozlint/formatters/compact.py

@@ -2,6 +2,8 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+import attr
+
 from ..result import Issue
 
 
@@ -25,7 +27,7 @@ class CompactFormatter(object):
             for err in errors:
                 assert isinstance(err, Issue)
 
-                d = {s: getattr(err, s) for s in err.__slots__}
+                d = attr.asdict(err)
                 d["column"] = ", col %s" % d["column"] if d["column"] else ""
                 d['level'] = d['level'].capitalize()
                 d['rule'] = d['rule'] or d['linter']

python/mozlint/mozlint/formatters/treeherder.py

@@ -2,6 +2,8 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+import attr
+
 from ..result import Issue
 
 
@@ -20,7 +22,7 @@ class TreeherderFormatter(object):
             for err in errors:
                 assert isinstance(err, Issue)
 
-                d = {s: getattr(err, s) for s in err.__slots__}
+                d = attr.asdict(err)
                 d["column"] = ":%s" % d["column"] if d["column"] else ""
                 d['level'] = d['level'].upper()
                 d['rule'] = d['rule'] or d['linter']

python/mozlint/mozlint/formatters/unix.py

@@ -2,6 +2,8 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+import attr
+
 from ..result import Issue
 
 
@@ -20,7 +22,7 @@ class UnixFormatter(object):
             for err in errors:
                 assert isinstance(err, Issue)
 
-                slots = {s: getattr(err, s) for s in err.__slots__}
+                slots = attr.asdict(err)
                 slots["path"] = slots['relpath']
                 slots["column"] = "%d:" % slots["column"] if slots["column"] else ""
                 slots["rule"] = slots["rule"] or slots["linter"]

python/mozlint/mozlint/result.py

@@ -3,10 +3,12 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from collections import defaultdict
-from json import dumps, JSONEncoder
+from json import JSONEncoder
 import os
 import mozpack.path as mozpath
 
+import attr
+
 
 class ResultSummary(object):
     """Represents overall result state from an entire lint run."""
@@ -55,6 +57,7 @@ class ResultSummary(object):
             self.suppressed_warnings[k] += v
 
 
+@attr.s(slots=True, kw_only=True)
 class Issue(object):
     """Represents a single lint issue and its related metadata.
 
@@ -72,62 +75,35 @@ class Issue(object):
     :param diff: a diff describing the changes that need to be made to the code
     """
 
-    __slots__ = (
-        "linter",
-        "path",
-        "message",
-        "lineno",
-        "column",
-        "hint",
-        "source",
-        "level",
-        "rule",
-        "lineoffset",
-        "diff",
-        "relpath",
+    linter = attr.ib()
+    path = attr.ib()
+    lineno = attr.ib(
+        default=None, converter=lambda lineno: int(lineno) if lineno else 0
     )
+    column = attr.ib(
+        default=None, converter=lambda column: int(column) if column else column
+    )
+    message = attr.ib()
+    hint = attr.ib(default=None)
+    source = attr.ib(default=None)
+    level = attr.ib(default=None, converter=lambda level: level or "error")
+    rule = attr.ib(default=None)
+    lineoffset = attr.ib(default=None)
+    diff = attr.ib(default=None)
+    relpath = attr.ib(init=False, default=None)
 
-    def __init__(
-        self,
-        linter,
-        path,
-        message,
-        lineno,
-        column=None,
-        hint=None,
-        source=None,
-        level=None,
-        rule=None,
-        lineoffset=None,
-        diff=None,
-        relpath=None,
-    ):
-        self.message = message
-        self.lineno = int(lineno) if lineno else 0
-        self.column = int(column) if column else column
-        self.hint = hint
-        self.source = source
-        self.level = level or "error"
-        self.linter = linter
-        self.rule = rule
-        self.lineoffset = lineoffset
-        self.diff = diff
-
+    def __attrs_post_init__(self):
         root = ResultSummary.root
         assert root is not None, 'Missing ResultSummary.root'
-        if os.path.isabs(path):
-            self.path = mozpath.normpath(path)
+        if os.path.isabs(self.path):
+            self.path = mozpath.normpath(self.path)
             if self.path.startswith(root):
                 self.relpath = mozpath.relpath(self.path, root)
             else:
                 self.relpath = self.path
         else:
-            self.path = mozpath.join(root, path)
-            self.relpath = mozpath.normpath(path)
-
-    def __repr__(self):
-        s = dumps(self, cls=IssueEncoder, indent=2)
-        return "Issue({})".format(s)
+            self.relpath = mozpath.normpath(self.path)
+            self.path = mozpath.join(root, self.path)
 
 
 class IssueEncoder(JSONEncoder):
@@ -140,7 +116,7 @@ class IssueEncoder(JSONEncoder):
 
     def default(self, o):
         if isinstance(o, Issue):
-            return {a: getattr(o, a) for a in o.__slots__}
+            return attr.asdict(o)
         return JSONEncoder.default(self, o)
 
 
@@ -154,14 +130,15 @@ def from_config(config, **kwargs):
     :param kwargs: same as :class:`~result.Issue`
     :returns: :class:`~result.Issue` object
     """
-    attrs = {}
-    for attr in Issue.__slots__:
-        attrs[attr] = kwargs.get(attr, config.get(attr))
+    args = {}
+    for arg in attr.fields(Issue):
+        if arg.init:
+            args[arg.name] = kwargs.get(arg.name, config.get(arg.name))
 
-    if not attrs["linter"]:
-        attrs["linter"] = config.get("name")
+    if not args["linter"]:
+        args["linter"] = config.get("name")
 
-    if not attrs["message"]:
-        attrs["message"] = config.get("description")
+    if not args["message"]:
+        args["message"] = config.get("description")
 
-    return Issue(**attrs)
+    return Issue(**args)

python/mozlint/test/test_formatters.py

@@ -4,6 +4,8 @@
 
 import json
 
+import attr
+
 import mozunit
 import mozpack.path as mozpath
 import pytest
@@ -121,7 +123,7 @@ def test_formatters(result, name):
     opts = EXPECTED[name]
     fmt = formatters.get(name, **opts["kwargs"])
     # encoding to str bypasses a UnicodeEncodeError in pytest
-    assert fmt(result).encode("utf-8") == opts["format"].encode("utf-8")
+    assert fmt(result) == opts["format"]
 
 
 def test_json_formatter(result):
@@ -130,10 +132,10 @@ def test_json_formatter(result):
 
     assert set(formatted.keys()) == set(result.issues.keys())
 
-    slots = Issue.__slots__
+    attrs = attr.fields(Issue)
     for errors in formatted.values():
         for err in errors:
-            assert all(s in err for s in slots)
+            assert all(a.name in err for a in attrs)
 
 
 if __name__ == "__main__":

python/mozlint/test/test_result.py

@@ -11,12 +11,12 @@ from mozlint.result import ResultSummary
 def test_issue_defaults():
     ResultSummary.root = '/fake/root'
 
-    issue = Issue('linter', 'path', 'message', None)
+    issue = Issue(linter='linter', path='path', message='message', lineno=None)
     assert issue.lineno == 0
     assert issue.column is None
     assert issue.level == 'error'
 
-    issue = Issue('linter', 'path', 'message', '1', column='2')
+    issue = Issue(linter='linter', path='path', message='message', lineno='1', column='2')
     assert issue.lineno == 1
     assert issue.column == 2