WIP: Google Sheets: auto-pad col_types when column count changes

[hidekoji]

Summary

• Adds automatic padding of col_types with ? (guess/default) when Google Sheet has more columns than specified
• Preserves existing column type configurations for original columns
• Works for both Desktop refresh and Server-side scheduled refresh

Problem

When a Google Sheet's column structure changes (columns are added) after initial import, refreshing the data source fails with:

Length of col_types is not compatible with columns found in sheets:
- 14 column types specified.
- But there are 15 columns found in sheets.

Solution

Instead of failing, the system now:

1. Detects the col_types length mismatch error
2. Extracts the actual column count from the error message
3. Pads the col_types string with ? for extra columns
4. Retries the read operation with the padded col_types

Test plan

• Test with Google Sheet that has exactly the specified column count
• Test with Google Sheet that has more columns than specified col_types
• Test with guessDataType=TRUE and guessDataType=FALSE
• Test with col_types=NULL (no column types specified)
• Test server-side scheduled refresh

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Improves Google Sheets refresh robustness by automatically handling col_types/column-count mismatches when a sheet gains new columns.

Changes:

• Add .pad_col_types_for_column_mismatch() to extend col_types with ? based on the column count parsed from the googlesheets4 error message.
• Add .read_sheet_with_col_types_padding() wrapper to retry googlesheets4::read_sheet() after padding on the specific mismatch error.
• Add unit tests for the padding helper.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
R/google_sheets.R	Adds internal helpers and routes getGoogleSheet() reads through retry-with-padding logic to avoid failures when column counts increase.
tests/testthat/test_google_sheets.R	Adds unit coverage for the col_types padding helper behavior.

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