Report method definition lineno when reporting property #200

RJ722 · 2020-03-14T14:41:38Z

Description

Previously, we reported the lineno on which the @property annotation was made. It, however makes sense to report the line on which the method is actually defined.

This was also non-consistent behavior b/w Vulture running on Python < 3.8 and >= 3.8.

Related Issue

#195 (comment)

Checklist:

My code follows the code style of this project.
My change requires a change to the documentation in the README file.
I have updated the documentation accordingly.
I have added an entry in CHANGELOG.md.
I have added tests to cover my changes.
All new and existing tests passed.

RJ722 · 2020-03-14T14:43:11Z

@jendrikseipp I took the liberty of adding some more simple, but more concrete tests to make sure that we do check for properties of individual unused items somewhere. Let me know if this doesn't right.

coveralls · 2020-03-14T14:43:39Z

Pull Request Test Coverage Report for Build 713

8 of 8 (100.0%) changed or added relevant lines in 2 files are covered.
No unchanged relevant lines lost coverage.
Overall coverage decreased (-0.5%) to 98.925%

Totals
Change from base Build 693:	-0.5%
Covered Lines:	552
Relevant Lines:	558

💛 - Coveralls

CHANGELOG.md

jendrikseipp · 2020-03-17T17:41:52Z

tests/test_scavenging.py

+    var = v.unused_vars[0]
+    assert var.name == "v"
+    assert var.first_lineno == 1
+    assert var.last_lineno == 1


Nice additional tests! Can you move them to a separate file, please? Maybe "test_items.py"?

jendrikseipp · 2020-03-17T18:04:04Z

vulture/core.py

+                # For python < 3.8, increment as many line numbers as there are
+                # decorators on the method.
+                # From Python3.8 onwards, lineno for property is the same as
+                # that of decorated method.


Let's turn this into a docstring and rewrite it slightly:

For decorated methods, Python < 3.8 uses the first decorator to report the first line number. To obtain the line number of the actual method definition (as in Python >= 3.8), we add the number of decorators to the line number. Obviously, this is only exact if all decorators use only one line.

Can we maybe make this an exact line number (even for multiline decorators)? For this, we would need to be able to retrieve the method's AST node from the property's AST node and call .lineno on it. Does the property's AST node have the relevant fields? You can inspect this on Python 2.7 with dir(node).

Obviously, this is only exact if all decorators use only one line.

Yeah, that is a problem. We need more test cases here.

For this, we would need to be able to retrieve the method's AST node from the property's AST node and call .lineno on it

I'm a little confused with this. Aren't AST nodes for property and method the same?

What I meant was the FunctionDef AST node and a decorator AST node. To retrieve the method line number from the FunctionDef node node, we could use lines.get_last_line_number(node.decorator_list[-1]). However, this is also just an approximation. Thinking about this again, I belive that it would be best to simply report the first line number of the first decorator for unused properties for Python 3.8+. This preserves the behaviour of Vulture for newer Python versions and is also more accurate for counting the size of the unused code chunk (if the property is unused, we also don't need it's decorators). Most importantly, it's easy to compute the line number accurately (should work for all Python versions, but deserves a comment about why we don't use node.lineno): node.decorator_list[0].lineno.

I tried lines.get_last_line_number(node.decorator_list[-1]) for a bunch of cases, and I agree about the inaccuracy, eg., it would fail here:

class TestFoo: @pytest.mark.parametrize( "line, codes", [ ("# noqa", ["all"]), ("## noqa", ["all"]), ], ) @property @pytest.mark.parametrize( "line, codes", [ ("# noqa", ["all"]), ], ) def test_noqa_regex_present(line, codes): pass

Also, I can't remember why this PR only targeted properties, and not all decorated functions? 😅

Anyways, I'll update this PR for all functions with the changes you mentioned above.

RJ722 · 2020-03-28T19:05:26Z

Apologies for the delay @jendrikseipp. I've updated the PR according to the recent discussion.

RJ722 · 2020-03-28T19:06:02Z

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Unreleased

 * Ignore unused import statements which occur in `__init__.py` (RJ722, #192).
+* Report first decorator's line number for decorated objects on Python 3.8+.
+  (RJ722, #200)


I'm not sure -- do we need to create an entry in CHANGELOG for this?

Yes, I think it's good to reflect the change somewhere.

jendrikseipp · 2020-03-29T09:48:34Z

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Unreleased

 * Ignore unused import statements which occur in `__init__.py` (RJ722, #192).
+* Report first decorator's line number for decorated objects on Python 3.8+.
+  (RJ722, #200)


Yes, I think it's good to reflect the change somewhere.

tests/test_report.py

vulture/lines.py

jendrikseipp · 2020-03-29T10:01:08Z

vulture/lines.py

+        # for newer Python versions, which is also more accurate for
+        # counting the size of the unused code chunk (if the property
+        # is unused, we also don't need it's decorators), we return the
+        # lineno of the first decorator, if there are any.


Hehe, I just copied over your comments.

vulture/lines.py

jendrikseipp · 2020-03-29T16:20:56Z

Thanks for your work and persistence!

RJ722 mentioned this pull request Mar 14, 2020

Ignore results annotated with '# noqa' #195

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Report method definition lineno when reporting property

07e762f

RJ722 force-pushed the prop-lineno branch from 47e6d98 to 07e762f Compare March 14, 2020 16:23

jendrikseipp requested changes Mar 17, 2020

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RJ722 commented Mar 28, 2020

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RJ722 force-pushed the prop-lineno branch from 46b636d to 5d44fe7 Compare March 28, 2020 19:07

Report first lineno for decorated objects on Python3.8+

2e035bb

RJ722 force-pushed the prop-lineno branch from 5d44fe7 to 2e035bb Compare March 28, 2020 19:11

jendrikseipp requested changes Mar 29, 2020

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Refactor lines.get_first_line_numer

7ab204d

jendrikseipp merged commit 672947b into jendrikseipp:master Mar 29, 2020

RJ722 deleted the prop-lineno branch March 29, 2020 16:29

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Report method definition lineno when reporting property #200

Report method definition lineno when reporting property #200

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Report method definition lineno when reporting property #200

Report method definition lineno when reporting property #200

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RJ722 commented Mar 14, 2020

Description

Related Issue

Checklist:

RJ722 commented Mar 14, 2020

coveralls commented Mar 14, 2020 • edited Loading

Pull Request Test Coverage Report for Build 713

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jendrikseipp commented Mar 29, 2020

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