Fix #4704: Preserve newlines in getPipedStdinData (#4878)

* Add test for #4704: getPipedStdinData should preserve newlines

* Fix #4704: Preserve newlines in getPipedStdinData

cmd/query.go

@@ -1,9 +1,9 @@
 package cmd
 
 import (
-	"bufio"
 	"context"
 	"fmt"
+	"io"
 	"os"
 	"slices"
 	"strings"
@@ -185,12 +185,13 @@ func getPipedStdinData() string {
 		error_helpers.ShowWarning("could not fetch information about STDIN")
 		return ""
 	}
-	stdinData := ""
 	if (fi.Mode()&os.ModeCharDevice) == 0 && fi.Size() > 0 {
-		scanner := bufio.NewScanner(os.Stdin)
-		for scanner.Scan() {
-			stdinData = fmt.Sprintf("%s%s", stdinData, scanner.Text())
+		data, err := io.ReadAll(os.Stdin)
+		if err != nil {
+			error_helpers.ShowWarning("could not read from STDIN")
+			return ""
 		}
+		return string(data)
 	}
-	return stdinData
+	return ""
 }

cmd/query_test.go

@@ -0,0 +1,54 @@
+package cmd
+
+import (
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestGetPipedStdinData_PreservesNewlines(t *testing.T) {
+	// Save original stdin
+	oldStdin := os.Stdin
+	defer func() { os.Stdin = oldStdin }()
+
+	// Create a temporary file to simulate piped input
+	tmpFile, err := os.CreateTemp("", "stdin-test-*")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	// Test input with multiple lines - matching the bug report example
+	testInput := "SELECT * FROM aws_account\nWHERE account_id = '123'\nAND region = 'us-east-1';"
+
+	// Write test input to the temp file
+	if _, err := tmpFile.WriteString(testInput); err != nil {
+		t.Fatalf("Failed to write to temp file: %v", err)
+	}
+
+	// Seek back to the beginning
+	if _, err := tmpFile.Seek(0, 0); err != nil {
+		t.Fatalf("Failed to seek temp file: %v", err)
+	}
+
+	// Replace stdin with our temp file
+	os.Stdin = tmpFile
+
+	// Call the function
+	result := getPipedStdinData()
+
+	// Clean up
+	tmpFile.Close()
+
+	// Verify that newlines are preserved
+	if result != testInput {
+		t.Errorf("getPipedStdinData() did not preserve newlines\nExpected: %q\nGot: %q", testInput, result)
+
+		// Show the difference more clearly
+		expectedLines := strings.Split(testInput, "\n")
+		resultLines := strings.Split(result, "\n")
+		t.Logf("Expected %d lines, got %d lines", len(expectedLines), len(resultLines))
+		t.Logf("Expected lines: %v", expectedLines)
+		t.Logf("Got lines: %v", resultLines)
+	}
+}