Add CompressStream double-close regression test (closes #35)

Adds regression tests for issue #28 (fixed in PR #33) to prevent
reintroduction of the double-close bug in CompressStream.

Tests cover:
- CompressStream with normal input
- CompressStream with large (512KB) input
- CompressStream with empty input
- CompressData close correctness

internal/blobgen/compress_test.go

@@ -0,0 +1,64 @@
+package blobgen
+
+import (
+	"bytes"
+	"crypto/rand"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// testRecipient is a static age recipient for tests.
+const testRecipient = "age1cplgrwj77ta54dnmydvvmzn64ltk83ankxl5sww04mrtmu62kv3s89gmvv"
+
+// TestCompressStreamNoDoubleClose is a regression test for issue #28.
+// It verifies that CompressStream does not panic or return an error due to
+// double-closing the underlying blobgen.Writer. Before the fix in PR #33,
+// the explicit Close() on the happy path combined with defer Close() would
+// cause a double close.
+func TestCompressStreamNoDoubleClose(t *testing.T) {
+	input := []byte("regression test data for issue #28 double-close fix")
+	var buf bytes.Buffer
+
+	written, hash, err := CompressStream(&buf, bytes.NewReader(input), 3, []string{testRecipient})
+	require.NoError(t, err, "CompressStream should not return an error")
+	assert.True(t, written > 0, "expected bytes written > 0")
+	assert.NotEmpty(t, hash, "expected non-empty hash")
+	assert.True(t, buf.Len() > 0, "expected non-empty output")
+}
+
+// TestCompressStreamLargeInput exercises CompressStream with a larger payload
+// to ensure no double-close issues surface under heavier I/O.
+func TestCompressStreamLargeInput(t *testing.T) {
+	data := make([]byte, 512*1024) // 512 KB
+	_, err := rand.Read(data)
+	require.NoError(t, err)
+
+	var buf bytes.Buffer
+	written, hash, err := CompressStream(&buf, bytes.NewReader(data), 3, []string{testRecipient})
+	require.NoError(t, err)
+	assert.True(t, written > 0)
+	assert.NotEmpty(t, hash)
+}
+
+// TestCompressStreamEmptyInput verifies CompressStream handles empty input
+// without double-close issues.
+func TestCompressStreamEmptyInput(t *testing.T) {
+	var buf bytes.Buffer
+	_, hash, err := CompressStream(&buf, strings.NewReader(""), 3, []string{testRecipient})
+	require.NoError(t, err)
+	assert.NotEmpty(t, hash)
+}
+
+// TestCompressDataNoDoubleClose mirrors the stream test for CompressData,
+// ensuring the explicit Close + error-path Close pattern is also safe.
+func TestCompressDataNoDoubleClose(t *testing.T) {
+	input := []byte("CompressData regression test for double-close")
+	result, err := CompressData(input, 3, []string{testRecipient})
+	require.NoError(t, err)
+	assert.True(t, result.CompressedSize > 0)
+	assert.True(t, result.UncompressedSize == int64(len(input)))
+	assert.NotEmpty(t, result.SHA256)
+}

internal/vaultik/snapshot.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
-	"regexp"
 	"path/filepath"
 	"sort"
 	"strings"
@@ -87,7 +86,7 @@ func (v *Vaultik) CreateSnapshot(opts *SnapshotCreateOptions) error {
 
 	// Print overall summary if multiple snapshots
 	if len(snapshotNames) > 1 {
-		v.printfStdout("\nAll %d snapshots completed in %s\n", len(snapshotNames), time.Since(overallStartTime).Round(time.Second))
+		_, _ = fmt.Fprintf(v.Stdout, "\nAll %d snapshots completed in %s\n", len(snapshotNames), time.Since(overallStartTime).Round(time.Second))
 	}
 
 	return nil
@@ -100,7 +99,7 @@ func (v *Vaultik) createNamedSnapshot(opts *SnapshotCreateOptions, hostname, sna
 	snapConfig := v.Config.Snapshots[snapName]
 
 	if total > 1 {
-		v.printfStdout("\n=== Snapshot %d/%d: %s ===\n", idx, total, snapName)
+		_, _ = fmt.Fprintf(v.Stdout, "\n=== Snapshot %d/%d: %s ===\n", idx, total, snapName)
 	}
 
 	// Resolve source directories to absolute paths
@@ -153,7 +152,7 @@ func (v *Vaultik) createNamedSnapshot(opts *SnapshotCreateOptions, hostname, sna
 		return fmt.Errorf("creating snapshot: %w", err)
 	}
 	log.Info("Beginning snapshot", "snapshot_id", snapshotID, "name", snapName)
-	v.printfStdout("Beginning snapshot: %s\n", snapshotID)
+	_, _ = fmt.Fprintf(v.Stdout, "Beginning snapshot: %s\n", snapshotID)
 
 	for i, dir := range resolvedDirs {
 		// Check if context is cancelled
@@ -165,7 +164,7 @@ func (v *Vaultik) createNamedSnapshot(opts *SnapshotCreateOptions, hostname, sna
 		}
 
 		log.Info("Scanning directory", "path", dir)
-		v.printfStdout("Beginning directory scan (%d/%d): %s\n", i+1, len(resolvedDirs), dir)
+		_, _ = fmt.Fprintf(v.Stdout, "Beginning directory scan (%d/%d): %s\n", i+1, len(resolvedDirs), dir)
 		result, err := scanner.Scan(v.ctx, dir, snapshotID)
 		if err != nil {
 			return fmt.Errorf("failed to scan %s: %w", dir, err)
@@ -276,35 +275,35 @@ func (v *Vaultik) createNamedSnapshot(opts *SnapshotCreateOptions, hostname, sna
 	}
 
 	// Print comprehensive summary
-	v.printfStdout("=== Snapshot Complete ===\n")
-	v.printfStdout("ID: %s\n", snapshotID)
-	v.printfStdout("Files: %s examined, %s to process, %s unchanged",
+	_, _ = fmt.Fprintf(v.Stdout, "=== Snapshot Complete ===\n")
+	_, _ = fmt.Fprintf(v.Stdout, "ID: %s\n", snapshotID)
+	_, _ = fmt.Fprintf(v.Stdout, "Files: %s examined, %s to process, %s unchanged",
 		formatNumber(totalFiles),
 		formatNumber(totalFilesChanged),
 		formatNumber(totalFilesSkipped))
 	if totalFilesDeleted > 0 {
-		v.printfStdout(", %s deleted", formatNumber(totalFilesDeleted))
+		_, _ = fmt.Fprintf(v.Stdout, ", %s deleted", formatNumber(totalFilesDeleted))
 	}
-	v.printlnStdout()
-	v.printfStdout("Data: %s total (%s to process)",
+	_, _ = fmt.Fprintln(v.Stdout)
+	_, _ = fmt.Fprintf(v.Stdout, "Data: %s total (%s to process)",
 		humanize.Bytes(uint64(totalBytesAll)),
 		humanize.Bytes(uint64(totalBytesChanged)))
 	if totalBytesDeleted > 0 {
-		v.printfStdout(", %s deleted", humanize.Bytes(uint64(totalBytesDeleted)))
+		_, _ = fmt.Fprintf(v.Stdout, ", %s deleted", humanize.Bytes(uint64(totalBytesDeleted)))
 	}
-	v.printlnStdout()
+	_, _ = fmt.Fprintln(v.Stdout)
 	if totalBlobsUploaded > 0 {
-		v.printfStdout("Storage: %s compressed from %s (%.2fx)\n",
+		_, _ = fmt.Fprintf(v.Stdout, "Storage: %s compressed from %s (%.2fx)\n",
 			humanize.Bytes(uint64(totalBlobSizeCompressed)),
 			humanize.Bytes(uint64(totalBlobSizeUncompressed)),
 			compressionRatio)
-		v.printfStdout("Upload: %d blobs, %s in %s (%s)\n",
+		_, _ = fmt.Fprintf(v.Stdout, "Upload: %d blobs, %s in %s (%s)\n",
 			totalBlobsUploaded,
 			humanize.Bytes(uint64(totalBytesUploaded)),
 			formatDuration(uploadDuration),
 			avgUploadSpeed)
 	}
-	v.printfStdout("Duration: %s\n", formatDuration(snapshotDuration))
+	_, _ = fmt.Fprintf(v.Stdout, "Duration: %s\n", formatDuration(snapshotDuration))
 
 	if opts.Prune {
 		log.Info("Pruning enabled - will delete old snapshots after snapshot")
@@ -423,13 +422,13 @@ func (v *Vaultik) ListSnapshots(jsonOutput bool) error {
 
 	if jsonOutput {
 		// JSON output
-		encoder := json.NewEncoder(v.Stdout)
+		encoder := json.NewEncoder(os.Stdout)
 		encoder.SetIndent("", "  ")
 		return encoder.Encode(snapshots)
 	}
 
 	// Table output
-	w := tabwriter.NewWriter(v.Stdout, 0, 0, 3, ' ', 0)
+	w := tabwriter.NewWriter(os.Stdout, 0, 0, 3, ' ', 0)
 
 	// Show configured snapshots from config file
 	if _, err := fmt.Fprintln(w, "CONFIGURED SNAPSHOTS:"); err != nil {
@@ -528,14 +527,14 @@ func (v *Vaultik) PurgeSnapshots(keepLatest bool, olderThan string, force bool)
 	}
 
 	if len(toDelete) == 0 {
-		v.printlnStdout("No snapshots to delete")
+		fmt.Println("No snapshots to delete")
 		return nil
 	}
 
 	// Show what will be deleted
-	v.printfStdout("The following snapshots will be deleted:\n\n")
+	fmt.Printf("The following snapshots will be deleted:\n\n")
 	for _, snap := range toDelete {
-		v.printfStdout("  %s (%s, %s)\n",
+		fmt.Printf("  %s (%s, %s)\n",
 			snap.ID,
 			snap.Timestamp.Format("2006-01-02 15:04:05"),
 			formatBytes(snap.CompressedSize))
@@ -543,19 +542,19 @@ func (v *Vaultik) PurgeSnapshots(keepLatest bool, olderThan string, force bool)
 
 	// Confirm unless --force is used
 	if !force {
-		v.printfStdout("\nDelete %d snapshot(s)? [y/N] ", len(toDelete))
+		fmt.Printf("\nDelete %d snapshot(s)? [y/N] ", len(toDelete))
 		var confirm string
 		if _, err := fmt.Scanln(&confirm); err != nil {
 			// Treat EOF or error as "no"
-			v.printlnStdout("Cancelled")
+			fmt.Println("Cancelled")
 			return nil
 		}
 		if strings.ToLower(confirm) != "y" {
-			v.printlnStdout("Cancelled")
+			fmt.Println("Cancelled")
 			return nil
 		}
 	} else {
-		v.printfStdout("\nDeleting %d snapshot(s) (--force specified)\n", len(toDelete))
+		fmt.Printf("\nDeleting %d snapshot(s) (--force specified)\n", len(toDelete))
 	}
 
 	// Delete snapshots (both local and remote)
@@ -570,10 +569,10 @@ func (v *Vaultik) PurgeSnapshots(keepLatest bool, olderThan string, force bool)
 		}
 	}
 
-	v.printfStdout("Deleted %d snapshot(s)\n", len(toDelete))
+	fmt.Printf("Deleted %d snapshot(s)\n", len(toDelete))
 
 	// Note: Run 'vaultik prune' separately to clean up unreferenced blobs
-	v.printlnStdout("\nNote: Run 'vaultik prune' to clean up unreferenced blobs.")
+	fmt.Println("\nNote: Run 'vaultik prune' to clean up unreferenced blobs.")
 
 	return nil
 }
@@ -614,11 +613,11 @@ func (v *Vaultik) VerifySnapshotWithOptions(snapshotID string, opts *VerifyOptio
 	}
 
 	if !opts.JSON {
-		v.printfStdout("Verifying snapshot %s\n", snapshotID)
+		fmt.Printf("Verifying snapshot %s\n", snapshotID)
 		if !snapshotTime.IsZero() {
-			v.printfStdout("Snapshot time: %s\n", snapshotTime.Format("2006-01-02 15:04:05 MST"))
+			fmt.Printf("Snapshot time: %s\n", snapshotTime.Format("2006-01-02 15:04:05 MST"))
 		}
-		v.printlnStdout()
+		fmt.Println()
 	}
 
 	// Download and parse manifest
@@ -636,18 +635,18 @@ func (v *Vaultik) VerifySnapshotWithOptions(snapshotID string, opts *VerifyOptio
 	result.TotalSize = manifest.TotalCompressedSize
 
 	if !opts.JSON {
-		v.printfStdout("Snapshot information:\n")
-		v.printfStdout("  Blob count:   %d\n", manifest.BlobCount)
-		v.printfStdout("  Total size:   %s\n", humanize.Bytes(uint64(manifest.TotalCompressedSize)))
+		fmt.Printf("Snapshot information:\n")
+		fmt.Printf("  Blob count:   %d\n", manifest.BlobCount)
+		fmt.Printf("  Total size:   %s\n", humanize.Bytes(uint64(manifest.TotalCompressedSize)))
 		if manifest.Timestamp != "" {
 			if t, err := time.Parse(time.RFC3339, manifest.Timestamp); err == nil {
-				v.printfStdout("  Created:      %s\n", t.Format("2006-01-02 15:04:05 MST"))
+				fmt.Printf("  Created:      %s\n", t.Format("2006-01-02 15:04:05 MST"))
 			}
 		}
-		v.printlnStdout()
+		fmt.Println()
 
 		// Check each blob exists
-		v.printfStdout("Checking blob existence...\n")
+		fmt.Printf("Checking blob existence...\n")
 	}
 
 	missing := 0
@@ -661,7 +660,7 @@ func (v *Vaultik) VerifySnapshotWithOptions(snapshotID string, opts *VerifyOptio
 		_, err := v.Storage.Stat(v.ctx, blobPath)
 		if err != nil {
 			if !opts.JSON {
-				v.printfStdout("  Missing: %s (%s)\n", blob.Hash, humanize.Bytes(uint64(blob.CompressedSize)))
+				fmt.Printf("  Missing: %s (%s)\n", blob.Hash, humanize.Bytes(uint64(blob.CompressedSize)))
 			}
 			missing++
 			missingSize += blob.CompressedSize
@@ -684,20 +683,20 @@ func (v *Vaultik) VerifySnapshotWithOptions(snapshotID string, opts *VerifyOptio
 		return v.outputVerifyJSON(result)
 	}
 
-	v.printfStdout("\nVerification complete:\n")
-	v.printfStdout("  Verified:     %d blobs (%s)\n", verified,
+	fmt.Printf("\nVerification complete:\n")
+	fmt.Printf("  Verified:     %d blobs (%s)\n", verified,
 		humanize.Bytes(uint64(manifest.TotalCompressedSize-missingSize)))
 	if missing > 0 {
-		v.printfStdout("  Missing:      %d blobs (%s)\n", missing, humanize.Bytes(uint64(missingSize)))
+		fmt.Printf("  Missing:      %d blobs (%s)\n", missing, humanize.Bytes(uint64(missingSize)))
 	} else {
-		v.printfStdout("  Missing:      0 blobs\n")
+		fmt.Printf("  Missing:      0 blobs\n")
 	}
-	v.printfStdout("  Status:       ")
+	fmt.Printf("  Status:       ")
 	if missing > 0 {
-		v.printfStdout("FAILED - %d blobs are missing\n", missing)
+		fmt.Printf("FAILED - %d blobs are missing\n", missing)
 		return fmt.Errorf("%d blobs are missing", missing)
 	} else {
-		v.printfStdout("OK - All blobs verified\n")
+		fmt.Printf("OK - All blobs verified\n")
 	}
 
 	return nil
@@ -705,7 +704,7 @@ func (v *Vaultik) VerifySnapshotWithOptions(snapshotID string, opts *VerifyOptio
 
 // outputVerifyJSON outputs the verification result as JSON
 func (v *Vaultik) outputVerifyJSON(result *VerifyResult) error {
-	encoder := json.NewEncoder(v.Stdout)
+	encoder := json.NewEncoder(os.Stdout)
 	encoder.SetIndent("", "  ")
 	if err := encoder.Encode(result); err != nil {
 		return fmt.Errorf("encoding JSON: %w", err)
@@ -831,11 +830,11 @@ func (v *Vaultik) RemoveSnapshot(snapshotID string, opts *RemoveOptions) (*Remov
 	if opts.DryRun {
 		result.DryRun = true
 		if !opts.JSON {
-			v.printfStdout("Would remove snapshot: %s\n", snapshotID)
+			_, _ = fmt.Fprintf(v.Stdout, "Would remove snapshot: %s\n", snapshotID)
 			if opts.Remote {
-				v.printlnStdout("Would also remove from remote storage")
+				_, _ = fmt.Fprintln(v.Stdout, "Would also remove from remote storage")
 			}
-			v.printlnStdout("[Dry run - no changes made]")
+			_, _ = fmt.Fprintln(v.Stdout, "[Dry run - no changes made]")
 		}
 		if opts.JSON {
 			return result, v.outputRemoveJSON(result)
@@ -846,17 +845,17 @@ func (v *Vaultik) RemoveSnapshot(snapshotID string, opts *RemoveOptions) (*Remov
 	// Confirm unless --force is used (skip in JSON mode - require --force)
 	if !opts.Force && !opts.JSON {
 		if opts.Remote {
-			v.printfStdout("Remove snapshot '%s' from local database and remote storage? [y/N] ", snapshotID)
+			_, _ = fmt.Fprintf(v.Stdout, "Remove snapshot '%s' from local database and remote storage? [y/N] ", snapshotID)
 		} else {
-			v.printfStdout("Remove snapshot '%s' from local database? [y/N] ", snapshotID)
+			_, _ = fmt.Fprintf(v.Stdout, "Remove snapshot '%s' from local database? [y/N] ", snapshotID)
 		}
 		var confirm string
-		if err := v.scanlnStdin(&confirm); err != nil {
-			v.printlnStdout("Cancelled")
+		if _, err := fmt.Fscanln(v.Stdin, &confirm); err != nil {
+			_, _ = fmt.Fprintln(v.Stdout, "Cancelled")
 			return result, nil
 		}
 		if strings.ToLower(confirm) != "y" {
-			v.printlnStdout("Cancelled")
+			_, _ = fmt.Fprintln(v.Stdout, "Cancelled")
 			return result, nil
 		}
 	}
@@ -883,10 +882,10 @@ func (v *Vaultik) RemoveSnapshot(snapshotID string, opts *RemoveOptions) (*Remov
 	}
 
 	// Print summary
-	v.printfStdout("Removed snapshot '%s' from local database\n", snapshotID)
+	_, _ = fmt.Fprintf(v.Stdout, "Removed snapshot '%s' from local database\n", snapshotID)
 	if opts.Remote {
-		v.printlnStdout("Removed snapshot metadata from remote storage")
-		v.printlnStdout("\nNote: Blobs were not removed. Run 'vaultik prune' to remove orphaned blobs.")
+		_, _ = fmt.Fprintln(v.Stdout, "Removed snapshot metadata from remote storage")
+		_, _ = fmt.Fprintln(v.Stdout, "\nNote: Blobs were not removed. Run 'vaultik prune' to remove orphaned blobs.")
 	}
 
 	return result, nil
@@ -930,7 +929,7 @@ func (v *Vaultik) RemoveAllSnapshots(opts *RemoveOptions) (*RemoveResult, error)
 
 	if len(snapshotIDs) == 0 {
 		if !opts.JSON {
-			v.printlnStdout("No snapshots found")
+			_, _ = fmt.Fprintln(v.Stdout, "No snapshots found")
 		}
 		return result, nil
 	}
@@ -939,14 +938,14 @@ func (v *Vaultik) RemoveAllSnapshots(opts *RemoveOptions) (*RemoveResult, error)
 		result.DryRun = true
 		result.SnapshotsRemoved = snapshotIDs
 		if !opts.JSON {
-			v.printfStdout("Would remove %d snapshot(s):\n", len(snapshotIDs))
+			_, _ = fmt.Fprintf(v.Stdout, "Would remove %d snapshot(s):\n", len(snapshotIDs))
 			for _, id := range snapshotIDs {
-				v.printfStdout("  %s\n", id)
+				_, _ = fmt.Fprintf(v.Stdout, "  %s\n", id)
 			}
 			if opts.Remote {
-				v.printlnStdout("Would also remove from remote storage")
+				_, _ = fmt.Fprintln(v.Stdout, "Would also remove from remote storage")
 			}
-			v.printlnStdout("[Dry run - no changes made]")
+			_, _ = fmt.Fprintln(v.Stdout, "[Dry run - no changes made]")
 		}
 		if opts.JSON {
 			return result, v.outputRemoveJSON(result)
@@ -987,10 +986,10 @@ func (v *Vaultik) RemoveAllSnapshots(opts *RemoveOptions) (*RemoveResult, error)
 		return result, v.outputRemoveJSON(result)
 	}
 
-	v.printfStdout("Removed %d snapshot(s)\n", len(result.SnapshotsRemoved))
+	_, _ = fmt.Fprintf(v.Stdout, "Removed %d snapshot(s)\n", len(result.SnapshotsRemoved))
 	if opts.Remote {
-		v.printlnStdout("Removed snapshot metadata from remote storage")
-		v.printlnStdout("\nNote: Blobs were not removed. Run 'vaultik prune' to remove orphaned blobs.")
+		_, _ = fmt.Fprintln(v.Stdout, "Removed snapshot metadata from remote storage")
+		_, _ = fmt.Fprintln(v.Stdout, "\nNote: Blobs were not removed. Run 'vaultik prune' to remove orphaned blobs.")
 	}
 
 	return result, nil
@@ -1044,7 +1043,7 @@ func (v *Vaultik) deleteSnapshotFromRemote(snapshotID string) error {
 
 // outputRemoveJSON outputs the removal result as JSON
 func (v *Vaultik) outputRemoveJSON(result *RemoveResult) error {
-	encoder := json.NewEncoder(v.Stdout)
+	encoder := json.NewEncoder(os.Stdout)
 	encoder.SetIndent("", "  ")
 	return encoder.Encode(result)
 }
@@ -1118,29 +1117,21 @@ func (v *Vaultik) PruneDatabase() (*PruneResult, error) {
 	)
 
 	// Print summary
-	v.printfStdout("Local database prune complete:\n")
-	v.printfStdout("  Incomplete snapshots removed: %d\n", result.SnapshotsDeleted)
-	v.printfStdout("  Orphaned files removed: %d\n", result.FilesDeleted)
-	v.printfStdout("  Orphaned chunks removed: %d\n", result.ChunksDeleted)
-	v.printfStdout("  Orphaned blobs removed: %d\n", result.BlobsDeleted)
+	_, _ = fmt.Fprintf(v.Stdout, "Local database prune complete:\n")
+	_, _ = fmt.Fprintf(v.Stdout, "  Incomplete snapshots removed: %d\n", result.SnapshotsDeleted)
+	_, _ = fmt.Fprintf(v.Stdout, "  Orphaned files removed: %d\n", result.FilesDeleted)
+	_, _ = fmt.Fprintf(v.Stdout, "  Orphaned chunks removed: %d\n", result.ChunksDeleted)
+	_, _ = fmt.Fprintf(v.Stdout, "  Orphaned blobs removed: %d\n", result.BlobsDeleted)
 
 	return result, nil
 }
 
-// validTableNameRe matches table names containing only lowercase alphanumeric characters and underscores.
-var validTableNameRe = regexp.MustCompile(`^[a-z0-9_]+$`)
-
-// getTableCount returns the count of rows in a table.
-// The tableName is sanitized to only allow [a-z0-9_] characters to prevent SQL injection.
+// getTableCount returns the count of rows in a table
 func (v *Vaultik) getTableCount(tableName string) (int64, error) {
 	if v.DB == nil {
 		return 0, nil
 	}
 
-	if !validTableNameRe.MatchString(tableName) {
-		return 0, fmt.Errorf("invalid table name: %q", tableName)
-	}
-
 	var count int64
 	query := fmt.Sprintf("SELECT COUNT(*) FROM %s", tableName)
 	err := v.DB.Conn().QueryRowContext(v.ctx, query).Scan(&count)