Circular fix applied involving Path and ComparePrimitivesByEqual

[nth10sd]

Create a testcase.py file:

from pathlib import Path
from tempfile import TemporaryDirectory

with TemporaryDirectory() as f:
    fn_ = Path(f) / "test.txt"
    fn_.write_text("Testing!\n")

    assert fn_.read_text() == "Testing!\n"  # No fixit error

    assert (Path(f) / "test.txt").samefile(fn_)  # Assert passes, so they are identical
    assert (Path(f) / "test.txt").read_text() == "Testing!\n"  # fixit shows an error

Run the following command once:

grep "shows an error" testcase.py ; fixit lint --diff testcase.py ; fixit fix --automatic testcase.py ; grep "shows an error" testcase.py

You will get the first output:

    assert (Path(f) / "test.txt").read_text() == "Testing!\n"  # fixit shows an error
testcase.py@11:11 CompareSingletonPrimitivesByIs: Comparisons to singleton primitives should not be done with == or !=, as they check equality rather than identiy. Use `is` or `is not` instead. (has autofix)
--- a/testcase.py
+++ b/testcase.py
@@ -10,2 +10,2 @@
     assert (Path(f) / "test.txt").samefile(fn_)  # Assert passes, so they are identical
-    assert (Path(f) / "test.txt").read_text() == "Testing!\n"  # fixit shows an error
+    assert (Path(f) / "test.txt").read_text() is "Testing!\n"  # fixit shows an error
🛠️  1 file checked, 1 file with errors, 1 auto-fix available 🛠️
testcase.py@11:11 CompareSingletonPrimitivesByIs: Comparisons to singleton primitives should not be done with == or !=, as they check equality rather than identiy. Use `is` or `is not` instead. (has autofix)
🛠️  1 file checked, 1 file with errors, 1 auto-fix available, 1 fix applied 🛠️
    assert (Path(f) / "test.txt").read_text() is "Testing!\n"  # fixit shows an error

Run the command again, you will get this second set of fixes back to the original:

    assert (Path(f) / "test.txt").read_text() is "Testing!\n"  # fixit shows an error
testcase.py@11:11 ComparePrimitivesByEqual: Don't use `is` or `is not` to compare primitives, as they compare references. Use == or != instead. (has autofix)
--- a/testcase.py
+++ b/testcase.py
@@ -10,2 +10,2 @@
     assert (Path(f) / "test.txt").samefile(fn_)  # Assert passes, so they are identical
-    assert (Path(f) / "test.txt").read_text() is "Testing!\n"  # fixit shows an error
+    assert (Path(f) / "test.txt").read_text() == "Testing!\n"  # fixit shows an error
🛠️  1 file checked, 1 file with errors, 1 auto-fix available 🛠️
testcase.py@11:11 ComparePrimitivesByEqual: Don't use `is` or `is not` to compare primitives, as they compare references. Use == or != instead. (has autofix)
🛠️  1 file checked, 1 file with errors, 1 auto-fix available, 1 fix applied 🛠️
    assert (Path(f) / "test.txt").read_text() == "Testing!\n"  # fixit shows an error

Run the command over and over again, it will keep suggesting and applying the fix in the circular manner repeatedly.

libcst 1.0.1 fixit 2.0.0.post1

[amyreese]

This should be fixed by #391