feat(format): add NoWrapCell for data-driven column minimum widths

[apstndb]

Summary

• Add NoWrapCell type that wraps any Cell to indicate its content should preferably not be wrapped
• Add deriveColumnHints() to compute PreferredMinWidth per column from NoWrapCell instances
• Update ColumnHint with PreferredMinWidth field (replaces reserved NoWrap bool)
• Add applyColumnFloors() shared helper with soft degradation: uses preferred min when budget allows, falls back to hard minimum when it doesn't fit
• Wrap NULL cells as NoWrapCell in spannerRowToRow()
• Reduce minColumnWidth from 4 to 1 (meaningful minimum is now data-driven)

Motivation

The hardcoded minColumnWidth = 4 was implicit knowledge that NULL is 4 characters. This change makes the constraint data-driven and soft: columns with NoWrapCell values prefer to be wide enough to avoid wrapping those values, but degrade gracefully when screen space is insufficient.

Test plan

• NoWrapCell type: Format/RawText delegation, WithText preserves wrapper, IsNoWrap helper
• deriveColumnHints: computes correct PreferredMinWidth from NoWrapCell widths
• All strategies respect PreferredMinWidth when space allows
• Graceful degradation when preferred mins exceed available width
• make check passes (test + lint + fmt-check)

Fixes #567

🤖 Generated with Claude Code

[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 significantly enhances the table formatting capabilities by introducing a data-driven approach to column width management. It allows specific cell contents to express a preference against wrapping, ensuring that short, important values remain intact when possible. The system now dynamically calculates preferred minimum widths and applies them with a soft degradation mechanism, providing a more intelligent and visually appealing layout that adapts gracefully to available screen space, moving away from rigid, hardcoded minimums.

Highlights

• New NoWrapCell Type: Introduced a NoWrapCell type that wraps any Cell to indicate its content should preferably not be wrapped, allowing for data-driven minimum column widths.
• Dynamic Preferred Minimum Width Calculation: Added deriveColumnHints() to compute PreferredMinWidth for each column by scanning NoWrapCell instances, ensuring short values like 'NULL' are preserved.
• Updated ColumnHint Structure: Modified the ColumnHint struct to include PreferredMinWidth (an integer) which replaces the previously reserved NoWrap bool field.
• Flexible Column Floor Application: Implemented applyColumnFloors() as a shared helper that intelligently applies per-column minimum widths, using preferred minimums when space allows and gracefully degrading to a hard minimum when the budget is exceeded.
• Reduced Hardcoded Minimum Column Width: Decreased the global minColumnWidth constant from 4 to 1, shifting the responsibility for meaningful minimums to the new data-driven NoWrapCell logic.
• NULL Cells Wrapped as NoWrapCell: Ensured that NULL cells are now wrapped as NoWrapCell instances in spannerRowToRow() and integration tests, allowing them to benefit from the new preferred minimum width logic.

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[github-actions]

Code Metrics Report

📊 View detailed coverage report (available for 7 days)

	main (f3a08a1)	#574 (cf150bc)	+/-
Coverage	70.7%	70.8%	+0.1%
Code to Test Ratio	1:1.2	1:1.3	+0.0
Test Execution Time	2m24s	1m9s	-1m15s

Details

  |                     | main (f3a08a1) | #574 (cf150bc) |  +/-   |
  |---------------------|----------------|----------------|--------|
+ | Coverage            |          70.7% |          70.8% |  +0.1% |
  |   Files             |             75 |             75 |      0 |
  |   Lines             |           6988 |           7007 |    +19 |
+ |   Covered           |           4945 |           4967 |    +22 |
+ | Code to Test Ratio  |          1:1.2 |          1:1.3 |   +0.0 |
  |   Code              |          16241 |          16274 |    +33 |
+ |   Test              |          21086 |          21183 |    +97 |
+ | Test Execution Time |          2m24s |           1m9s | -1m15s |

Code coverage of files in pull request scope (90.8% → 91.7%)

Files	Coverage	+/-	Status
internal/mycli/execute_sql.go	82.6%	+1.3%	affected
internal/mycli/format/config.go	100.0%	0.0%	modified
internal/mycli/format/width.go	96.9%	-0.6%	modified
internal/mycli/format/width_strategy.go	100.0%	0.0%	modified
internal/mycli/format/width_strategy_greedy.go	97.8%	-0.1%	modified
internal/mycli/format/width_strategy_marginal.go	96.3%	-0.1%	modified
internal/mycli/format/width_strategy_proportional.go	100.0%	0.0%	modified
internal/mycli/metrics/execution_metrics.go	91.1%	+4.4%	affected
internal/mycli/row_iter.go	87.0%	0.0%	modified

---

Reported by octocov

[gemini-code-assist]

Code Review

This pull request introduces a NoWrapCell type and a PreferredMinWidth concept to enhance column width calculation in table formatting. The minColumnWidth is reduced from 4 to 1, and a new mechanism is implemented to identify cells that should preferably not be wrapped (e.g., "NULL", "true", "false"). The system now calculates a PreferredMinWidth for each column based on the maximum width of its NoWrapCell contents. Column width strategies have been updated to utilize these PreferredMinWidth hints, applying them as a soft constraint when space allows, and gracefully degrading to the hard minColumnWidth of 1 if the total preferred width exceeds available screen space. This ensures important short values remain intact while maintaining flexibility in layout. New unit and integration tests have been added to validate this behavior, particularly for NULL values.

[apstndb]

/gemini summary

[gemini-code-assist]

Summary of Changes

This pull request refactors the column width calculation logic to be data-driven, moving away from a hardcoded minimum width. It introduces a NoWrapCell type to allow cell content to express a preference against wrapping, which is then used to compute preferred minimum widths for columns. This enables a more intelligent and visually appealing table layout that prioritizes keeping short, important values intact while gracefully degrading when screen space is limited.

Highlights

• New NoWrapCell Type: Introduced a NoWrapCell type that wraps any Cell to indicate its content should preferably not be wrapped, allowing for data-driven minimum column widths.
• Dynamic Preferred Minimum Width Calculation: Added deriveColumnHints() to compute PreferredMinWidth for each column by scanning NoWrapCell instances, ensuring short values like 'NULL' are preserved.
• Updated ColumnHint Structure: Modified the ColumnHint struct to include PreferredMinWidth (an integer) which replaces the previously reserved NoWrap bool field.
• Flexible Column Floor Application: Implemented applyColumnFloors() as a shared helper that intelligently applies per-column minimum widths, using preferred minimums when space allows and gracefully degrading to a hard minimum when the budget is exceeded.
• Reduced Hardcoded Minimum Column Width: Decreased the global minColumnWidth constant from 4 to 1, shifting the responsibility for meaningful minimums to the new data-driven NoWrapCell logic.
• NULL Cells Wrapped as NoWrapCell: Ensured that NULL cells are now wrapped as NoWrapCell instances in spannerRowToRow() and integration tests, allowing them to benefit from the new preferred minimum width logic.

Changelog

• internal/mycli/format/config.go
  • Added NoWrapCell struct to wrap existing Cell types and indicate content should not be wrapped.
  • Implemented WithText method for NoWrapCell to preserve wrapping when text is replaced.
  • Added IsNoWrap helper function to check if a Cell is a NoWrapCell.
• internal/mycli/format/width.go
  • Reduced minColumnWidth constant from 4 to 1, shifting the primary minimum width enforcement to data-driven logic.
  • Introduced deriveColumnHints function to scan rows and calculate PreferredMinWidth for columns based on NoWrapCell instances.
  • Added applyColumnFloors function to apply column minimums, prioritizing PreferredMinWidth when budget allows and falling back to minColumnWidth otherwise.
  • Updated CalculateWidthWithStrategy to use deriveColumnHints.
• internal/mycli/format/width_strategy.go
  • Modified ColumnHint struct to replace the NoWrap bool field with PreferredMinWidth int.
• internal/mycli/format/width_strategy_greedy.go
  • Updated CalculateWidths method to accept hints []ColumnHint parameter.
  • Replaced the explicit minColumnWidth loop with a call to applyColumnFloors.
• internal/mycli/format/width_strategy_marginal.go
  • Updated CalculateWidths method to accept hints []ColumnHint parameter.
  • Replaced the explicit minColumnWidth loop with a call to applyColumnFloors.
• internal/mycli/format/width_strategy_proportional.go
  • Updated CalculateWidths method to accept hints []ColumnHint parameter.
  • Replaced the explicit minColumnWidth loop with a call to applyColumnFloors.
• internal/mycli/format/width_strategy_test.go
  • Added TestStrategyRespectsPreferredMinWidth to verify strategies honor preferred minimum widths when space is ample.
  • Added TestStrategyGracefulDegradation to ensure strategies fall back to hard minimums when preferred widths exceed available space.
• internal/mycli/format/width_test.go
  • Added TestNoWrapCell to verify the behavior of the new NoWrapCell type, including Format, RawText, IsNoWrap, and WithText.
  • Added TestDeriveColumnHints to confirm correct calculation of PreferredMinWidth from NoWrapCell instances.
  • Added TestDeriveColumnHintsNoNoWrap to ensure PreferredMinWidth remains 0 when no NoWrapCell instances are present.
• internal/mycli/integration_test.go
  • Modified the n helper function to return a format.NoWrapCell wrapping a StyledCell for NULL values.
  • Updated paramCasesToStmtResults to wrap StyledCell for NULL values in a format.NoWrapCell.
• internal/mycli/row_iter.go
  • Wrapped StyledCell instances for NULL values in a format.NoWrapCell when converting Spanner rows to internal format rows.

Activity

• Gemini Code Assist provided an initial summary of the changes in the pull request.
• github-actions[bot] posted a Code Metrics Report detailing coverage and test execution time changes.
• apstndb requested a new summary from Gemini Code Assist.