Regex caret (^) not working properly for scope: raw when there are over 999 characters in a Markdown file.

[michael-nok]

Check for existing issues

• Completed

Environment

• Windows 10
• Direct download of Windows executable
• Vale 2.29.1 or later

Describe the bug / provide steps to reproduce it

The changes implemented by this commit causes the problem to exist: f769fcd

	// NOTE: If the `ctx` document is large (as could be the case with
	// `scope: raw`) this is *slow*. Thus, the cap at 1k.
	//
	// TODO: Actually fix this.

I have a rule that looks for incorrectly indented content. It uses the following token:

extends: existence
message: 'Content must be indented using 4x spaces each time. "%s"'
level: error
nonword: true
scope: raw
tokens:
  - '^[ ]{1,3}\`'

When the Markdown file contains 999 characters or more (i.e. ctx > 1000), the ^ part of the token stops using the start of the line properly and invents (hallucinates) new starting positions.

Attached are sample files that exactly show the spillover in the logic:
vale.zip

Consequently, text with four spaces before the first ` is flagged as incorrect, and the starting position for the ^ is column 1.

Using the vale.exe from release 2.29.0 does not have this problem.

[twitchard]

I ran into this too.

My reproduction

cd $(mktemp -d)                                                             
cat <<EOF > .vale.ini
StylesPath = ./.vale/styles
MinAlertLevel = suggestion
[*.txt]
BasedOnStyles = MyStyle
EOF
mkdir -p ./.vale/styles/MyStyle
cat <<EOF > .vale/styles/MyStyle/MyRule.yml
extends: script
message: "Error %s"
scope: raw
script: |
  matches := [{begin: 0, end: 1}, {begin: 997, end: 998}]
EOF
(
  echo a
  echo b
  for x in `seq 993`; do
    echo -n "x";
  done
  echo b
) >> test-999-bytes.txt
cp test-999-bytes.txt test-1001-bytes.txt
echo x >> test-1001-bytes.txt
vale test-999-bytes.txt
vale test-1001-bytes.txt

Produces

 test-999-bytes.txt
 1:1    warning  Error a  MyStyle.MyRule
 3:994  warning  Error b  MyStyle.MyRule

✖ 0 errors, 2 warnings and 0 suggestions in 1 file.

 test-1001-bytes.txt
 1:1  warning  Error a  MyStyle.MyRule
 2:1  warning  Error b  MyStyle.MyRule

✖ 0 errors, 2 warnings and 0 suggestions in 1 file.