Implement better handling of long files and fixes

src/rapids_pre_commit_hooks/lint.py

@@ -17,6 +17,7 @@
 import contextlib
 import functools
 import itertools
+import re
 import warnings
 
 
@@ -70,6 +71,8 @@ def __repr__(self):
 
 
 class Linter:
+    NEWLINE_RE = re.compile("[\r\n]")
+
     def __init__(self, filename, content):
         self.filename = filename
         self.content = content
@@ -117,31 +120,52 @@ def print_warnings(self, fix_applied=False):
 
             for replacement in warning.replacements:
                 line_index = self.line_for_pos(replacement.pos[0])
+                newtext = replacement.newtext
+                if match := self.NEWLINE_RE.search(newtext):
+                    newtext = newtext[: match.start()] + "..."
+                    long = True
+                else:
+                    long = False
+
                 print(f"In file {self.filename}:{line_index + 1}:")
-                self.print_highlighted_code(replacement.pos, replacement.newtext)
+                self.print_highlighted_code(replacement.pos, newtext)
                 if fix_applied:
-                    print("note: suggested fix applied")
+                    if long:
+                        print("note: suggested fix applied but is too long to display")
+                    else:
+                        print("note: suggested fix applied")
                 else:
-                    print("note: suggested fix")
+                    if long:
+                        print(
+                            "note: suggested fix is too long to display, use --fix to "
+                            "apply it"
+                        )
+                    else:
+                        print("note: suggested fix")
                 print()
 
     def print_highlighted_code(self, pos, replacement=""):
         line_index = self.line_for_pos(pos[0])
         line_pos = self.lines[line_index]
         left = pos[0] - line_pos[0]
 
+        if replacement:
+            replacement = f" {replacement}"
+
         if self.line_for_pos(pos[1]) == line_index:
             right = pos[1] - line_pos[0]
+            long = False
         else:
             right = line_pos[1] - line_pos[0]
+            long = True
         length = right - left
 
         print(self.content[line_pos[0] : line_pos[1]])
         print(" " * left, end="")
         if length == 0:
             print(f"^{replacement}")
         else:
-            print(f"{'~' * length}{replacement}")
+            print(f"{'~' * (length - 1)}{'|' if long else '~'}{replacement}")
 
     def line_for_pos(self, index):
         @functools.total_ordering

test/rapids_pre_commit_hooks/test_lint.py

@@ -142,6 +142,14 @@ def binary_file(self):
             f.seek(0)
             yield f
 
+    @pytest.fixture
+    def long_file(self):
+        with tempfile.NamedTemporaryFile("w+") as f:
+            f.write("This is a long file\nIt has multiple lines\n")
+            f.flush()
+            f.seek(0)
+            yield f
+
     def the_check(self, linter, args):
         assert args.check_test
         linter.add_warning((0, 5), "say good bye instead").add_replacement(
@@ -150,6 +158,14 @@ def the_check(self, linter, args):
         if linter.content[5] != "!":
             linter.add_warning((5, 5), "use punctuation").add_replacement((5, 5), ",")
 
+    def long_file_check(self, linter, args):
+        linter.add_warning((0, len(linter.content)), "this is a long file")
+
+    def long_fix_check(self, linter, args):
+        linter.add_warning((0, 19), "this is a long line").add_replacement(
+            (0, 19), "This is a long file\nIt's even longer now"
+        )
+
     def test_no_warnings_no_fix(self, hello_world_file, capsys):
         with patch("sys.argv", ["check-test", "--check-test", hello_world_file.name]):
             m = LintMain()
@@ -191,7 +207,7 @@ def test_warnings_no_fix(self, hello_world_file, capsys):
 
 In file {hello_world_file.name}:1:
 Hello world!
-~~~~~Good bye
+~~~~~ Good bye
 note: suggested fix
 
 In file {hello_world_file.name}:1:
@@ -201,7 +217,7 @@ def test_warnings_no_fix(self, hello_world_file, capsys):
 
 In file {hello_world_file.name}:1:
 Hello world!
-     ^,
+     ^ ,
 note: suggested fix
 
 """
@@ -226,7 +242,7 @@ def test_warnings_fix(self, hello_world_file, capsys):
 
 In file {hello_world_file.name}:1:
 Hello world!
-~~~~~Good bye
+~~~~~ Good bye
 note: suggested fix applied
 
 In file {hello_world_file.name}:1:
@@ -236,7 +252,7 @@ def test_warnings_fix(self, hello_world_file, capsys):
 
 In file {hello_world_file.name}:1:
 Hello world!
-     ^,
+     ^ ,
 note: suggested fix applied
 
 """
@@ -269,7 +285,7 @@ def test_multiple_files(self, hello_world_file, hello_file, capsys):
 
 In file {hello_world_file.name}:1:
 Hello world!
-~~~~~Good bye
+~~~~~ Good bye
 note: suggested fix applied
 
 In file {hello_world_file.name}:1:
@@ -279,7 +295,7 @@ def test_multiple_files(self, hello_world_file, hello_file, capsys):
 
 In file {hello_world_file.name}:1:
 Hello world!
-     ^,
+     ^ ,
 note: suggested fix applied
 
 In file {hello_file.name}:1:
@@ -289,13 +305,13 @@ def test_multiple_files(self, hello_world_file, hello_file, capsys):
 
 In file {hello_file.name}:1:
 Hello!
-~~~~~Good bye
+~~~~~ Good bye
 note: suggested fix applied
 
 """
         )
 
-    def test_binary_file(self, binary_file, capsys):
+    def test_binary_file(self, binary_file):
         mock_linter = Mock(wraps=Linter)
         with patch(
             "sys.argv",
@@ -314,3 +330,83 @@ def test_binary_file(self, binary_file, capsys):
             with m.execute() as ctx:
                 ctx.add_check(self.the_check)
         mock_linter.assert_not_called()
+
+    def test_long_file(self, long_file, capsys):
+        with patch(
+            "sys.argv",
+            [
+                "check-test",
+                long_file.name,
+            ],
+        ), pytest.raises(SystemExit, match=r"^1$"):
+            m = LintMain()
+            with m.execute() as ctx:
+                ctx.add_check(self.long_file_check)
+                ctx.add_check(self.long_fix_check)
+        assert (
+            long_file.read()
+            == """This is a long file
+It has multiple lines
+"""
+        )
+        captured = capsys.readouterr()
+        assert (
+            captured.out
+            == f"""In file {long_file.name}:1:
+This is a long file
+~~~~~~~~~~~~~~~~~~~
+warning: this is a long line
+
+In file {long_file.name}:1:
+This is a long file
+~~~~~~~~~~~~~~~~~~~ This is a long file...
+note: suggested fix is too long to display, use --fix to apply it
+
+In file {long_file.name}:1:
+This is a long file
+~~~~~~~~~~~~~~~~~~|
+warning: this is a long file
+
+"""
+        )
+
+    def test_long_file_fix(self, long_file, capsys):
+        with patch(
+            "sys.argv",
+            [
+                "check-test",
+                "--fix",
+                long_file.name,
+            ],
+        ), pytest.raises(SystemExit, match=r"^1$"):
+            m = LintMain()
+            with m.execute() as ctx:
+                ctx.add_check(self.long_file_check)
+                ctx.add_check(self.long_fix_check)
+        assert (
+            long_file.read()
+            == """This is a long file
+It's even longer now
+It has multiple lines
+"""
+        )
+        captured = capsys.readouterr()
+        assert (
+            captured.out
+            == f"""In file {long_file.name}:1:
+This is a long file
+~~~~~~~~~~~~~~~~~~~
+warning: this is a long line
+
+In file {long_file.name}:1:
+This is a long file
+~~~~~~~~~~~~~~~~~~~ This is a long file...
+note: suggested fix applied but is too long to display
+
+In file {long_file.name}:1:
+This is a long file
+~~~~~~~~~~~~~~~~~~|
+warning: this is a long file
+
+"""
+        )