Code block: dedent code before validating it

If it's indented too far, the AST parser will fail.

2 files changed, 17 insertions, 4 deletions

diff --git a/bot/cogs/codeblock/instructions.py b/bot/cogs/codeblock/instructions.py
index c25b2af5d..56b85a34f 100644
--- a/bot/cogs/codeblock/instructions.py
+++ b/bot/cogs/codeblock/instructions.py
@@ -70,7 +70,7 @@ def _get_no_ticks_message(content: str) -> Optional[str]:
     """If `content` is Python/REPL code, return instructions on using code blocks."""
     log.trace("Creating instructions for a missing code block.")
 
-    if parsing.is_repl_code(content) or parsing.is_python_code(content):
+    if parsing.is_python_code(content):
         example_blocks = _get_example("python")
         return (
             "It looks like you're trying to paste code into this channel.\n\n"
@@ -132,7 +132,7 @@ def _get_no_lang_message(content: str) -> Optional[str]:
     """
     log.trace("Creating instructions for a missing language.")
 
-    if parsing.is_repl_code(content) or parsing.is_python_code(content):
+    if parsing.is_python_code(content):
         example_blocks = _get_example("python")
 
         # Note that _get_bad_ticks_message expects the first line to have two newlines.
diff --git a/bot/cogs/codeblock/parsing.py b/bot/cogs/codeblock/parsing.py
index 5b4cb9fdd..ea007b6f1 100644
--- a/bot/cogs/codeblock/parsing.py
+++ b/bot/cogs/codeblock/parsing.py
@@ -3,6 +3,7 @@
 import ast
 import logging
 import re
+import textwrap
 from typing import NamedTuple, Optional, Sequence
 
 from bot import constants
@@ -98,7 +99,7 @@ def find_code_blocks(message: str) -> Optional[Sequence[CodeBlock]]:
     return code_blocks
 
 
-def is_python_code(content: str) -> bool:
+def _is_python_code(content: str) -> bool:
     """Return True if `content` is valid Python consisting of more than just expressions."""
     log.trace("Checking if content is Python code.")
     try:
@@ -120,7 +121,7 @@ def is_python_code(content: str) -> bool:
         return False
 
 
-def is_repl_code(content: str, threshold: int = 3) -> bool:
+def _is_repl_code(content: str, threshold: int = 3) -> bool:
     """Return True if `content` has at least `threshold` number of (I)Python REPL-like lines."""
     log.trace(f"Checking if content is (I)Python REPL code using a threshold of {threshold}.")
 
@@ -145,6 +146,18 @@ def is_repl_code(content: str, threshold: int = 3) -> bool:
     return False
 
 
+def is_python_code(content: str) -> bool:
+    """Return True if `content` is valid Python code or (I)Python REPL output."""
+    dedented = textwrap.dedent(content)
+
+    # Parse AST twice in case _fix_indentation ends up breaking code due to its inaccuracies.
+    return (
+        _is_python_code(dedented)
+        or _is_repl_code(dedented)
+        or _is_python_code(_fix_indentation(content))
+    )
+
+
 def parse_bad_language(content: str) -> Optional[BadLanguage]:
     """
     Return information about a poorly formatted Python language in code block `content`.