fix: ai fixes

Author: rustyconover

CLAUDE.md

@@ -0,0 +1,65 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Textplot is a DuckDB extension that provides text-based data visualization functions. It's a C++ extension built using the DuckDB extension template and CI tools, creating ASCII/Unicode charts directly from SQL queries.
+
+## Build Commands
+
+```bash
+# Build release version
+make release
+
+# Build debug version
+make debug
+
+# Run tests (requires build first)
+make test           # runs against release build
+make test_debug     # runs against debug build
+
+# Format code
+make format
+
+# Clean build artifacts
+make clean
+```
+
+The build uses CMake under the hood. Build outputs go to `build/release/` or `build/debug/`.
+
+## Architecture
+
+### Extension Entry Point
+- `src/textplot_extension.cpp` - Registers all scalar functions with DuckDB via `LoadInternal()`
+
+### SQL Functions
+Each visualization function has a corresponding implementation file:
+
+| Function | Files | Purpose |
+|----------|-------|---------|
+| `tp_bar()` | `textplot_bar.cpp/.hpp` | Horizontal bar charts with thresholds and colors |
+| `tp_density()` | `textplot_density.cpp/.hpp` | Density plots/histograms from arrays |
+| `tp_sparkline()` | `textplot_sparkline.cpp/.hpp` | Compact trend lines with multiple modes |
+| `tp_qr()` | `textplot_qr.cpp/.hpp` | QR code generation |
+
+### Pattern
+Each function follows the DuckDB scalar function pattern:
+- `Textplot*Bind()` - Validates and binds arguments at plan time
+- `Textplot*()` - Executes the function at runtime
+- Functions accept named parameters (e.g., `width := 20`, `style := 'ascii'`)
+
+### Directory Structure
+- `src/` - C++ source files
+- `src/include/` - Header files
+- `test/sql/` - SQLLogicTest files (`.test` extension)
+- `duckdb/` - DuckDB submodule (git submodule)
+- `extension-ci-tools/` - Build system submodule
+
+## Testing
+
+Tests use DuckDB's SQLLogicTest format in `test/sql/`. See https://duckdb.org/dev/sqllogictest/intro.html for syntax.
+
+## Dependencies
+
+This extension uses vcpkg for dependency management. The `vcpkg.json` in the project root defines dependencies, and `extension_config.cmake` configures the extension build.

src/textplot_bar.cpp

@@ -234,7 +234,13 @@ void TextplotBar(DataChunk &args, ExpressionState &state, Vector &result) {
 	const auto &bind_data = func_expr.bind_info->Cast<TextplotBarBindData>();
 
 	UnaryExecutor::Execute<double, string_t>(value_vector, result, args.size(), [&](double value) {
-		const auto proportion = std::clamp((value - bind_data.min) / (bind_data.max - bind_data.min), 0.0, 1.0);
+		double proportion;
+		if (bind_data.max == bind_data.min) {
+			// Avoid division by zero: if value equals min/max, show full bar; otherwise empty
+			proportion = (value >= bind_data.min) ? 1.0 : 0.0;
+		} else {
+			proportion = std::clamp((value - bind_data.min) / (bind_data.max - bind_data.min), 0.0, 1.0);
+		}
 		const auto filled_blocks = static_cast<int64_t>(std::round(bind_data.width * proportion));
 
 		string bar;

src/textplot_density.cpp

@@ -187,8 +187,11 @@ void TextplotDensity(DataChunk &args, ExpressionState &state, Vector &result) {
 		// Count values in each bin
 		for (const double val : data_items) {
 			auto binIndex = static_cast<int>((val - minVal) / binWidth);
+			// Clamp to valid range to handle floating point edge cases
+			if (binIndex < 0)
+				binIndex = 0;
 			if (binIndex >= bind_data.width)
-				binIndex = bind_data.width - 1; // Handle edge case
+				binIndex = bind_data.width - 1;
 			bins[binIndex]++;
 		}
 
@@ -208,6 +211,9 @@ void TextplotDensity(DataChunk &args, ExpressionState &state, Vector &result) {
 		int markerPos = -1;
 		if (!std::isnan(markerValue) && markerValue >= minVal && markerValue <= maxVal) {
 			markerPos = static_cast<int>((markerValue - minVal) / binWidth);
+			// Clamp to valid range to handle floating point edge cases
+			if (markerPos < 0)
+				markerPos = 0;
 			if (markerPos >= bind_data.width)
 				markerPos = bind_data.width - 1;
 		}

src/textplot_sparkline.cpp

@@ -115,7 +115,11 @@ std::string generateAbsoluteSparkline(const double *data, int size, int width,
 
 	if (max_val == min_val) {
 		int mid_idx = characters.size() / 2;
-		return std::string(width, characters[mid_idx][0]);
+		std::string result;
+		for (int i = 0; i < width; i++) {
+			result += characters[mid_idx];
+		}
+		return result;
 	}
 
 	std::string result;
@@ -125,10 +129,16 @@ std::string generateAbsoluteSparkline(const double *data, int size, int width,
 	for (int i = 0; i < width; i++) {
 		int start_idx = static_cast<int>(i * data_per_char);
 		int end_idx = static_cast<int>((i + 1) * data_per_char);
+		// Clamp indices to valid range
+		if (start_idx >= size)
+			start_idx = size - 1;
 		if (end_idx > size)
 			end_idx = size;
 		if (start_idx >= end_idx)
 			end_idx = start_idx + 1;
+		// Final safety check: ensure we don't exceed array bounds
+		if (end_idx > size)
+			end_idx = size;
 
 		double sum = 0.0;
 		for (int j = start_idx; j < end_idx; j++) {