Highlight blank lines and provide additional suggestions for E9989 pe…

…p8-errors (#913)

CHANGELOG.md

@@ -20,6 +20,9 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - The `UnnecessaryIndexingChecker` now checks for a greater variety of loop/comprehension indexes.
 - Modified configuration behaviour so when providing a config file, it only needs to contain the configuration options you want overridden.
 - Added the option `load_default_config` to `check_errors` and `check_all` to specify whether to automatically load the PythonTA default config.
+- For the message display of E9989 `pep8-errors`, all "blank line" messages are now custom-rendered, i.e., blank lines
+  are now highlighted instead of function signatures and instruction strings are added for required blank lines that
+  are missing.
 
 ### Bug Fixes
 

python_ta/reporters/node_printers.py

@@ -3,6 +3,8 @@
 
 from astroid import nodes
 
+NEW_BLANK_LINE_MESSAGE = "# INSERT NEW BLANK LINE HERE"
+
 
 def render_message(msg, node, source_lines):
     """Render a message based on type."""
@@ -128,6 +130,131 @@ def render_missing_space_in_doctest(msg, _node, source_lines=None):
     yield from render_context(line + 1, line + 3, source_lines)
 
 
+def render_pep8_errors(msg, _node, source_lines=None):
+    """Render a PEP8 error message."""
+    if "expected 1 blank line," in msg.msg:
+        yield from render_pep8_errors_e301(msg, _node, source_lines)
+    elif "expected 2 blank lines," in msg.msg:
+        yield from render_pep8_errors_e302(msg, _node, source_lines)
+    elif "too many blank lines" in msg.msg:
+        yield from render_pep8_errors_e303(msg, _node, source_lines)
+    elif "blank lines found after function decorator" in msg.msg:
+        yield from render_pep8_errors_e304(msg, _node, source_lines)
+    elif "expected 2 blank lines after class or function definition" in msg.msg:
+        yield from render_pep8_errors_e305(msg, _node, source_lines)
+    elif "expected 1 blank line before a nested definition" in msg.msg:
+        yield from render_pep8_errors_e306(msg, _node, source_lines)
+    else:
+        yield from render_generic(msg, _node, source_lines)
+
+
+def render_blank_line(line):
+    """Render a blank line for a PEP8 error message."""
+    yield (line + 1, slice(None, None), LineType.ERROR, " " * 28)
+
+
+def render_pep8_errors_e301(msg, _node, source_lines=None):
+    """Render a PEP8 expected 1 blank line message."""
+    line = msg.line - 1
+    yield from render_context(line - 1, line + 1, source_lines)
+    body = source_lines[line]
+    indentation = len(body) - len(body.lstrip())
+    yield (
+        None,
+        slice(None, None),
+        LineType.ERROR,
+        body[:indentation] + NEW_BLANK_LINE_MESSAGE + " " * indentation,
+    )
+    yield from render_context(msg.line, msg.line + 2, source_lines)
+
+
+def render_pep8_errors_e302(msg, _node, source_lines=None):
+    """Render a PEP8 expected 2 blank lines message."""
+    line = msg.line - 1
+    if "found 0" in msg.msg:
+        yield from render_context(line - 1, line + 1, source_lines)
+        yield from (
+            (
+                None,
+                slice(None, None),
+                LineType.ERROR,
+                NEW_BLANK_LINE_MESSAGE,
+            )
+            for _ in range(0, 2)
+        )
+    else:
+        line -= 1
+        yield from render_context(line - 1, line + 1, source_lines)
+        yield from render_blank_line(line)
+        yield (None, slice(None, None), LineType.ERROR, NEW_BLANK_LINE_MESSAGE)
+    yield from render_context(msg.line, msg.line + 2, source_lines)
+
+
+def render_pep8_errors_e303(msg, _node, source_lines=None):
+    """Render a PEP8 too many blank lines message."""
+    line = msg.line - 1
+    while source_lines[line - 1].strip() == "":
+        line -= 1
+    yield from render_context(line - 1, line + 1, source_lines)
+    body = source_lines[msg.line - 1]
+    indentation = len(body) - len(body.lstrip())
+    yield from (
+        (curr_line, slice(None, None), LineType.ERROR, " " * (indentation + 28))
+        for curr_line in range(line + 1, msg.line)
+    )
+    yield from render_context(msg.line, msg.line + 2, source_lines)
+
+
+def render_pep8_errors_e304(msg, _node, source_lines=None):
+    """Render a PEP8 blank lines found after function decorator message."""
+    line = msg.line - 1
+    while source_lines[line - 1].strip() == "":
+        line -= 1
+    yield from render_context(line - 1, line + 1, source_lines)
+    yield from (
+        (curr_line, slice(None, None), LineType.ERROR, " " * 28)
+        for curr_line in range(line + 1, msg.line)
+    )
+    yield from render_context(msg.line, msg.line + 2, source_lines)
+
+
+def render_pep8_errors_e305(msg, _node, source_lines=None):
+    """Render a PEP8 expected 2 blank lines after class or function definition message."""
+    line = msg.line - 1
+    if "found 0" in msg.msg:
+        yield from render_context(line - 1, line + 1, source_lines)
+        yield from (
+            (
+                None,
+                slice(None, None),
+                LineType.ERROR,
+                NEW_BLANK_LINE_MESSAGE,
+            )
+            for _ in range(0, 2)
+        )
+    else:
+        line -= 1
+        yield from render_context(line - 1, line + 1, source_lines)
+        yield from render_blank_line(line)
+        yield (None, slice(None, None), LineType.ERROR, NEW_BLANK_LINE_MESSAGE)
+    yield from render_context(msg.line, msg.line + 2, source_lines)
+
+
+def render_pep8_errors_e306(msg, _node, source_lines=None):
+    """Render a PEP8 expected 1 blank line before a nested definition message."""
+    line = msg.line - 1
+    yield from render_context(line - 1, line + 1, source_lines)
+    body = source_lines[line]
+    indentation = len(body) - len(body.lstrip())
+    yield (
+        None,
+        slice(None, None),
+        LineType.ERROR,
+        body[:indentation] + NEW_BLANK_LINE_MESSAGE + " " * indentation,
+    )
+    yield from render_context(msg.line, msg.line + 2, source_lines)
+
+
 CUSTOM_MESSAGES = {
     "missing-module-docstring": render_missing_docstring,
     "missing-class-docstring": render_missing_docstring,
@@ -137,6 +264,7 @@ def render_missing_space_in_doctest(msg, _node, source_lines=None):
     "missing-return-type": render_missing_return_type,
     "too-many-arguments": render_too_many_arguments,
     "missing-space-in-doctest": render_missing_space_in_doctest,
+    "pep8-errors": render_pep8_errors,
 }