Refactor is_inside_quotes()

[rolandwalker]

Description

• Rename without underscore, as it might be used in another file.
• Recognize backtick quoting, including doubled backticks as escapes.
• Accept negative numbers for pos.
• escaped should not be toggled to True unless inside a double- or single-quoted string.
• Return a string or False, typed as Literal.
• Optimize: is not in is much faster than looping.

Motivation: to improve completions which start with backtick.

xref #1564 .

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the AUTHORS file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .

[github-actions]

Findings

1. Regression: enum value suggestions suppressed for backtick-quoted identifiers.
   _enum_value_suggestion now treats any non-False return from is_inside_quotes as “inside quotes”, which includes 'backtick'. That will block enum suggestions for \table`.`column`even though backticks are identifier quotes, not string literals. Action: Restrict this check to'single'/'double'only. For example:if is_inside_quotes(...) in ['single', 'double']:. File: mycli/packages/completion_engine.py:21-27`

2. Edge case: cursor between doubled backticks is treated as outside quotes.
   If a user types an escaped backtick inside a backtick-quoted identifier, the cursor between the two backticks (e.g., select `a|b``) is still inside the identifier. The current toggle logic flips off after the first backtick, sois_inside_quoteswould returnFalseat that cursor position. That can re-enable completions unexpectedly. Action: Consider handling doubled-backtick escape inside backticks, or document that this edge case is acceptable. File:mycli/packages/completion_engine.py:56-68`

Missing Tests / Edge Cases

1. Add a test for enum suggestions with backtick-quoted identifiers to prevent regression.
   Suggested case: text="select t.c = " should still trigger enum value suggestions.
   File: test/test_completion_engine.py

2. Add a test for cursor between doubled backticks if you choose to support that behavior.
   File: test/test_completion_engine.py

Notes

• No security concerns found.
• I did not run tests locally.

If you want, I can draft the test cases and a minimal fix for the enum suggestion behavior.

[rolandwalker]

Addressed both of the Codex findings. The doubling of backticks as escapes was a good point.

[scottnemes]

Could you give some examples of what you're addressing here? It's unclear to me what the goal is. I.e. I see:

select "json = no suggestions
select 'json = no suggestions
select `jso = suggestions after three characters
select ``js = suggestions after two characters

[rolandwalker]

Sorry if I was unclear @scottnemes . This is just an enabling refactor, which does not itself change any functionality other than fixing some bugs in which "inside quotes" was wrongly determined.

But, we would need this to attack #1564 .

[github-actions]

Findings

1. Potential IndexError for pos > len(text)
is_inside_quotes() now loops for index in range(0, pos) and indexes text[index]. If callers pass a pos larger than len(text), this will raise IndexError. Previously text[:pos] was safe for oversized positions. Suggest clamping pos = min(pos, len(text)) after the negative-index normalization.
   File: mycli/packages/completion_engine.py

2. Edge-case semantics for negative positions
   The new normalization pos = len(text) + pos + 1 changes meaning vs prior slicing. For example pos=-2 now scans up to len-1 (inclusive), which is not the same as text[: -2] behavior. That may be intended, but it’s a behavioral change for existing callers using negative positions. If this is deliberate, consider a short comment or a test covering pos=-len(text) and pos<-len(text) so the semantics are locked.
   File: mycli/packages/completion_engine.py

Missing tests / edge cases

1. Add a test for pos > len(text) to ensure it doesn’t throw and returns a sensible value (likely False).
   File: test/test_completion_engine.py

If you want, I can propose a small patch to clamp pos and add the test.