fix(format): fix table overflow when column count exceeds available width

[apstndb]

Summary

Fix table output overflowing screen width when column count is large (e.g., INFORMATION_SCHEMA.COLUMNS with 20 columns). The root cause was adjustToSum being unable to reduce column widths below the minimum unique header width threshold, leaving all columns at that floor even when their sum far exceeds the available width.

Key Changes

• width.go: Add equal-distribution fallback to adjustToSum when threshold clipping is insufficient. Each column gets at least width 1 to avoid zero-width columns that bypass tabwrap.Wrap. When numCols × 1 > limit, the 1-character overflow per column is unavoidable but minimal.
• width_strategy_greedy.go: Guard remainder distribution with remainder > 0 check. Previously, when applyColumnFloors caused total width to exceed availableWidth, the negative remainder would subtract width from a column, creating a zero-width column that bypasses wrapping entirely.
• width_test.go: Add adjustToSum test case for many-column overflow. Add INFORMATION_SCHEMA.COLUMNS-like test case to TestCalculateWidth with total-width assertion that accounts for unavoidable overflow.

Behavior at extreme widths

When numCols × minColumnWidth + overhead > screenWidth (e.g., 20 columns at screenWidth=80), the table will overflow by at most numCols × minColumnWidth + overhead - screenWidth characters (1 char in the COLUMNS case). This is the minimum possible overflow — every column gets exactly 1 character of content width.

Test Plan

• make check passes
• TestAdjustToSum/many_columns_overflow_falls_back_to_equal_distribution verifies fallback
• TestCalculateWidth/many_columns_like_INFORMATION_SCHEMA.COLUMNS verifies end-to-end at screenWidth=120
• Manual verification with embedded emulator

Fixes #575

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves an issue where tables with a large number of columns, such as INFORMATION_SCHEMA.COLUMNS, would overflow the screen width due to the column width adjustment logic failing to adequately reduce widths. The changes introduce a more robust fallback mechanism for distributing column widths, ensuring that tables remain within the available screen space while maintaining readability, even in extreme cases where many columns are present.

Highlights

• Column Width Adjustment: Implemented an equal-distribution fallback in adjustToSum to prevent table overflow when threshold clipping is insufficient, ensuring each column maintains a minimum width of 1.
• Greedy Width Strategy Refinement: Added a remainder > 0 guard to the remainder distribution logic in width_strategy_greedy.go to prevent the creation of zero-width columns.
• New Test Cases: Introduced new test cases for adjustToSum to cover many-column overflow and an INFORMATION_SCHEMA.COLUMNS-like scenario for TestCalculateWidth, including an assertion for total table width.

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[gemini-code-assist]

Code Review

This pull request addresses a table formatting bug where a large number of columns could cause the output to overflow the screen width. The fix involves modifying adjustToSum to fall back to an equal distribution of column widths when the normal clipping mechanism fails, guaranteeing a minimum width of 1 for each column. A related change in width_strategy_greedy.go prevents negative remainders from being applied to column widths. The changes are accompanied by new test cases that cover these overflow scenarios. My review did not identify any issues with the proposed implementation.

[github-actions]

Code Metrics Report

📊 View detailed coverage report (available for 7 days)

	main (88680c9)	#576 (fdae9e8)	+/-
Coverage	70.8%	70.8%	+0.0%
Code to Test Ratio	1:1.3	1:1.3	-0.1
Test Execution Time	1m11s	1m13s	+2s

Details

  |                     | main (88680c9) | #576 (fdae9e8) |  +/-  |
  |---------------------|----------------|----------------|-------|
+ | Coverage            |          70.8% |          70.8% | +0.0% |
  |   Files             |             75 |             75 |     0 |
  |   Lines             |           7007 |           7025 |   +18 |
+ |   Covered           |           4967 |           4980 |   +13 |
- | Code to Test Ratio  |          1:1.3 |          1:1.3 |  -0.1 |
  |   Code              |          16274 |          16299 |   +25 |
+ |   Test              |          21183 |          21212 |   +29 |
- | Test Execution Time |          1m11s |          1m13s |   +2s |

Code coverage of files in pull request scope (90.1% → 89.2%)

Files	Coverage	+/-	Status
internal/mycli/execute_sql.go	81.2%	-1.4%	affected
internal/mycli/format/width.go	96.4%	-0.5%	modified
internal/mycli/format/width_strategy_greedy.go	97.9%	+0.0%	modified
internal/mycli/metrics/execution_metrics.go	86.6%	-4.5%	affected

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Reported by octocov