vi-mode - Bug - Fix freeze when using _i"/_a" in escaped string

[LeeLaffan]

Change Description

The fix is for the bug in Issue #1657.
This affects code in operator pending mode, so the editor will freeze when using:

• v i/a "
• c i/a "
• d i/a "
• y i/a "

This occurs as when the escape character is found, it does not move the character forward/back, causing an infinite loop of finding the escape char.

As shown in this seek backward example, I have changed it to skip over 2 chars (the escape and the quote char). I did the same for when seeking forward.

  ;; Before
  ((and escape-char)
    (char= prev-char escape-char))
   
  ;; After 
  ((and escape-char 
            (character-at point -2) ;; Bound check
            (char= (character-at point -2) escape-char))
    (character-offset point -2))

This behaviour to ignore escape chars, which seems intended for Lem's vi-mode(just bugged), does match vanilla vim so good to have.

Testing

I have updated the tests to account for this case.
This image shows the rendered test outputs which can help you decipher the string in the tests in you want:

Other Bugs

I found some more bugs that are existing already with this functionality, but no more editor freezes, just unexpected behavious in some cases.
I hope to fix them with a bit of changes to the logic around finding quotes specifically.

• Both have different but unexpected behavior when they are before the first quote/after the last quote
• Both do not gracefully fail in all cases(one "). This is particularly annoying when doing d_" or c_" where you don't have the visual feedback

Feature

• Both do not mimic vim seek ahead in line with operator pending mode

[cxxxr]

Thank you!