task 436: handle loadFromFile close errors

2 files changed, 31 insertions, 5 deletions

diff --git a/internal/flamegraph/iordata.go b/internal/flamegraph/iordata.go
index 4a562e3..76e438a 100644
--- a/internal/flamegraph/iordata.go
+++ b/internal/flamegraph/iordata.go
@@ -144,19 +144,27 @@ func (iod iorData) serializeToFile(flamegraphName string) (retErr error) {
 	return nil
 }
 
-func (iod *iorData) loadFromFile(filename string) error {
+func (iod *iorData) loadFromFile(filename string) (retErr error) {
 	file, err := os.Open(filename)
 	if err != nil {
-		return err
+		return fmt.Errorf("open %s: %w", filename, err)
 	}
-	defer file.Close()
+	defer func() {
+		if err := file.Close(); err != nil {
+			retErr = errors.Join(retErr, fmt.Errorf("close file %s: %w", filename, err))
+		}
+	}()
 
 	decoder := zstd.NewReader(file)
-	defer decoder.Close()
+	defer func() {
+		if err := decoder.Close(); err != nil {
+			retErr = errors.Join(retErr, fmt.Errorf("close zstd reader for %s: %w", filename, err))
+		}
+	}()
 
 	var records map[recordKey]Counter
 	if err := gob.NewDecoder(decoder).Decode(&records); err != nil {
-		return err
+		return fmt.Errorf("decode ior records from %s: %w", filename, err)
 	}
 	if records == nil {
 		records = make(map[recordKey]Counter)
diff --git a/internal/flamegraph/iordata_test.go b/internal/flamegraph/iordata_test.go
index ee07a90..722cad3 100644
--- a/internal/flamegraph/iordata_test.go
+++ b/internal/flamegraph/iordata_test.go
@@ -3,6 +3,8 @@ package flamegraph
 import (
 	"bytes"
 	"errors"
+	"os"
+	"path/filepath"
 	"strings"
 	"syscall"
 	"testing"
@@ -328,6 +330,22 @@ func TestSerializeToFileHostnameErrorReturnsError(t *testing.T) {
 	}
 }
 
+func TestLoadFromFileCorruptDataReturnsContext(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "corrupt.ior.zst")
+	if err := os.WriteFile(path, []byte("not-a-valid-zstd-stream"), 0o600); err != nil {
+		t.Fatalf("write corrupt file: %v", err)
+	}
+
+	iod := newIorData()
+	err := iod.loadFromFile(path)
+	if err == nil {
+		t.Fatal("Expected corrupt file to return an error")
+	}
+	if !strings.Contains(err.Error(), "decode ior records from") {
+		t.Fatalf("Expected decode context, got %v", err)
+	}
+}
+
 func bothArraysHaveSameElements(a, b []string) bool {
 	if len(a) != len(b) {
 		return false