feat: switch to positional instrumenting from line-oriented

Author: pashagolub

internal/cli/report.go

@@ -73,21 +73,21 @@ func ReportSummary(coverageFile string) error {
 	}
 
 	// Print overall coverage
-	fmt.Printf("Overall Coverage: %.2f%%\n\n", cov.TotalLineCoveragePercent())
+	fmt.Printf("Overall Coverage: %.2f%%\n\n", cov.TotalPositionCoveragePercent())
 
 	// Print per-file coverage
 	fmt.Println("File Coverage:")
-	for file, hits := range cov.Files {
+	for file, posHits := range cov.Positions {
 		covered := 0
-		for _, count := range hits {
+		for _, count := range posHits {
 			if count > 0 {
 				covered++
 			}
 		}
-		total := len(hits)
-		percent := cov.LineCoveragePercent(file)
+		total := len(posHits)
+		percent := cov.PositionCoveragePercent(file)
 
-		fmt.Printf("  %s: %.2f%% (%d/%d lines)\n", file, percent, covered, total)
+		fmt.Printf("  %s: %.2f%% (%d/%d positions)\n", file, percent, covered, total)
 	}
 
 	return nil

internal/cli/run.go

@@ -98,6 +98,7 @@ func Run(ctx context.Context, config *Config, searchPath string) (int, error) {
 
 	// Step 7: Collect coverage
 	collector := coverage.NewCollector()
+
 	if err := collector.CollectFromRuns(testRuns); err != nil {
 		return 1, fmt.Errorf("coverage collection failed: %w", err)
 	}
@@ -125,7 +126,7 @@ func Run(ctx context.Context, config *Config, searchPath string) (int, error) {
 }
 
 // PrintVerbose prints a message if verbose mode is enabled
-func PrintVerbose(config *Config, format string, args ...interface{}) {
+func PrintVerbose(config *Config, format string, args ...any) {
 	if config.Verbose {
 		fmt.Printf(format+"\n", args...)
 	}

internal/coverage/collector.go

@@ -53,23 +53,24 @@ func (c *Collector) AddSignal(signal runner.CoverageSignal) error {
 
 // addSignalUnsafe adds a signal without locking (internal use when lock is already held)
 func (c *Collector) addSignalUnsafe(signal runner.CoverageSignal) error {
-	// Parse signal ID to extract file, line, and branch
-	file, line, branch, err := instrument.ParseSignalID(signal.SignalID)
+	// Parse signal ID to extract file, startPos, length, and branch
+	file, startPos, length, branch, err := instrument.ParseSignalID(signal.SignalID)
 	if err != nil {
 		return fmt.Errorf("invalid signal ID: %w", err)
 	}
 
-	// Add line or branch coverage
+	// Add position-based coverage only
 	if branch == "" {
-		// Line coverage - increment hit count
-		if existingCount, exists := c.coverage.Files[file][line]; exists {
-			c.coverage.AddLine(file, line, existingCount+1)
+		// Position coverage - increment hit count
+		posKey := fmt.Sprintf("%d:%d", startPos, length)
+		if existingCount, exists := c.coverage.Positions[file][posKey]; exists {
+			c.coverage.AddPosition(file, startPos, length, existingCount+1)
 		} else {
-			c.coverage.AddLine(file, line, 1)
+			c.coverage.AddPosition(file, startPos, length, 1)
 		}
 	} else {
 		// Branch coverage (placeholder for future)
-		branchKey := fmt.Sprintf("%d:%s", line, branch)
+		branchKey := fmt.Sprintf("%d:%d:%s", startPos, length, branch)
 		c.coverage.AddBranch(file, branchKey, 1)
 	}
 
@@ -97,32 +98,41 @@ func (c *Collector) Merge(other *Collector) error {
 	other.mu.Lock()
 	defer other.mu.Unlock()
 
-	for file, otherHits := range other.coverage.Files {
-		// Merge line hit counts
-		for line, count := range otherHits {
-			if existingCount, exists := c.coverage.Files[file][line]; exists {
-				c.coverage.AddLine(file, line, existingCount+count)
+	// Merge position hit counts only
+	for file, otherPosHits := range other.coverage.Positions {
+		for posKey, count := range otherPosHits {
+			// Parse position key to get startPos and length
+			var startPos, length int
+			_, err := fmt.Sscanf(posKey, "%d:%d", &startPos, &length)
+			if err != nil {
+				continue // Skip invalid keys
+			}
+
+			if existingCount, exists := c.coverage.Positions[file][posKey]; exists {
+				c.coverage.AddPosition(file, startPos, length, existingCount+count)
 			} else {
-				c.coverage.AddLine(file, line, count)
+				c.coverage.AddPosition(file, startPos, length, count)
 			}
 		}
 	}
+
 	return nil
 }
 
-// GetFileCoverage returns coverage data for a specific file (simplified)
-func (c *Collector) GetFileCoverage(filePath string) FileHits {
+// GetFilePositionCoverage returns position coverage data for a specific file
+func (c *Collector) GetFilePositionCoverage(filePath string) PositionHits {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	return c.coverage.Files[filePath]
+	return c.coverage.Positions[filePath]
 }
 
 // GetFileList returns a list of all files with coverage data
 func (c *Collector) GetFileList() []string {
 	c.mu.Lock()
 	defer c.mu.Unlock()
+
 	var files []string
-	for file := range c.coverage.Files {
+	for file := range c.coverage.Positions {
 		files = append(files, file)
 	}
 	return files
@@ -132,5 +142,5 @@ func (c *Collector) GetFileList() []string {
 func (c *Collector) TotalCoveragePercent() float64 {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	return c.coverage.TotalLineCoveragePercent()
+	return c.coverage.TotalPositionCoveragePercent()
 }