controller: .fab volume legs stream via docker cp (fixes the containerized path-strand data loss, IA finding 1 HIGH) — zero shared paths both deployment shapes; export fails LOUD on any missing/empty claimed tar (no hollow bundles); import validates BEFORE it destroys (hollow bundle → app untouched); docker_run_volume_path_gate.py extinguishes the class (Tier-1/2 mounts documented host-visible)

Claude-Session: https://claude.ai/code/session_01GzammAMzsJTgpQHqxwM2bC

controller/internal/appexport/export.go

@@ -2,6 +2,7 @@ package appexport
 
 import (
 	"archive/tar"
+	"bytes"
 	"compress/gzip"
 	"context"
 	"fmt"
@@ -324,7 +325,10 @@ func (e *Exporter) executeExport(req ExportRequest, job *Job) {
 		e.debugf("HDD data exported: subdirs=%v hasData=%v", manifest.HDDSubdirs, manifest.HasHDDData)
 	} else {
 		e.debugf("exporting Docker volumes for %s", req.StackName)
-		e.exportVolumeData(req.StackName, dataDir, manifest)
+		if err := e.exportVolumeData(req.StackName, dataDir, manifest); err != nil {
+			e.failJob(job, step, fmt.Sprintf("Kötet mentése sikertelen: %v", err))
+			return
+		}
 		e.debugf("volume data exported: volumes=%v hasData=%v", manifest.VolumeNames, manifest.HasVolumeData)
 	}
 	e.debugf("step 3 (user data) done in %v", time.Since(stepStart))
@@ -336,6 +340,13 @@ func (e *Exporter) executeExport(req ExportRequest, job *Job) {
 	job.setStep(step, "running", "")
 	stepStart = time.Now()
 
+	// v0.125.0 fail-loud guard (scenario B): never package a bundle whose manifest claims data
+	// that is not actually in the staging tree.
+	if err := assertBundleDataComplete(tmpDir, manifest); err != nil {
+		e.failJob(job, step, fmt.Sprintf("A csomag hiányos lenne — az export leállt: %v", err))
+		return
+	}
+
 	// Calculate total size
 	manifest.TotalSizeBytes = calcDirSize(tmpDir)
 	e.debugf("total bundle content size: %s (%d bytes)", humanizeBytes(manifest.TotalSizeBytes), manifest.TotalSizeBytes)
@@ -583,14 +594,17 @@ func (e *Exporter) exportHDDData(stackName, dataDir string, manifest *Manifest)
 			continue
 		}
 		subdir := filepath.Base(mount)
-		manifest.HDDSubdirs = append(manifest.HDDSubdirs, subdir)
 
 		tarPath := filepath.Join(hddDir, subdir+".tar")
 		e.debugf("tarring HDD mount: %s → %s", mount, tarPath)
 		tarStart := time.Now()
 		if err := tarDirectory(mount, tarPath); err != nil {
-			e.logger.Printf("[WARN] Export: failed to tar %s: %v", mount, err)
+			// v0.125.0: claim the subdir ONLY on success — a claimed-but-absent tar would trip
+			// the packaging assertion; an honestly-skipped mount stays out of the manifest.
+			e.logger.Printf("[WARN] Export: failed to tar %s (excluded from the bundle): %v", mount, err)
+			os.Remove(tarPath)
 		} else {
+			manifest.HDDSubdirs = append(manifest.HDDSubdirs, subdir)
 			if info, _ := os.Stat(tarPath); info != nil {
 				e.debugf("HDD tar complete: %s (%s) in %v", subdir, humanizeBytes(info.Size()), time.Since(tarStart))
 			}
@@ -599,8 +613,76 @@ func (e *Exporter) exportHDDData(stackName, dataDir string, manifest *Manifest)
 	manifest.HasHDDData = len(manifest.HDDSubdirs) > 0
 }
 
-// exportVolumeData exports Docker named volumes for apps without HDD storage.
-func (e *Exporter) exportVolumeData(stackName, dataDir string, manifest *Manifest) {
+// dockerExec is the docker-CLI seam (v0.125.0): runs `docker args...` with optional
+// stdin/stdout STREAMING and returns captured stderr (truncated). The volume legs stream tars
+// over the docker API (docker cp) — NEVER via `docker run -v <controller-path>` host mounts,
+// which the daemon resolves against the GUEST filesystem and silently strands the tar when the
+// controller itself runs containerized (the v0.124.0 HIGH finding). Package var so unit tests
+// inject a recorder (no docker on test boxes).
+var dockerExec = func(ctx context.Context, stdin io.Reader, stdout io.Writer, args ...string) (string, error) {
+	cmd := exec.CommandContext(ctx, "docker", args...)
+	cmd.Stdin = stdin
+	cmd.Stdout = stdout
+	var errBuf bytes.Buffer
+	cmd.Stderr = &errBuf
+	err := cmd.Run()
+	stderr := strings.TrimSpace(errBuf.String())
+	if len(stderr) > 500 {
+		stderr = stderr[:500] + "..."
+	}
+	return stderr, err
+}
+
+// withVolumeHelper creates a stopped helper container pinning volName at /vol, runs fn(cid),
+// and ALWAYS force-removes the helper — including on fn failure (no leaked alpine containers).
+func (e *Exporter) withVolumeHelper(volName string, fn func(cid string) error) error {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	var cidBuf bytes.Buffer
+	stderr, err := dockerExec(ctx, nil, &cidBuf, "create", "-v", volName+":/vol", "alpine", "true")
+	cancel()
+	if err != nil {
+		return fmt.Errorf("creating helper container for volume %s: %s — %w", volName, stderr, err)
+	}
+	cid := strings.TrimSpace(cidBuf.String())
+	defer func() {
+		rmCtx, rmCancel := context.WithTimeout(context.Background(), 30*time.Second)
+		defer rmCancel()
+		if _, rmErr := dockerExec(rmCtx, nil, nil, "rm", "-f", cid); rmErr != nil {
+			e.logger.Printf("[WARN] appexport: helper container %s cleanup failed: %v", cid, rmErr)
+		}
+	}()
+	return fn(cid)
+}
+
+// exportVolumeTar streams one volume's content into tarPath via `docker cp <cid>:/vol/. -`
+// (tar on stdout — zero shared paths; live-probed 2026-07-13: content, subdirs, symlinks,
+// empty files and uid/gid all round-trip).
+func (e *Exporter) exportVolumeTar(volName, tarPath string) error {
+	return e.withVolumeHelper(volName, func(cid string) error {
+		f, err := os.Create(tarPath)
+		if err != nil {
+			return fmt.Errorf("creating %s: %w", tarPath, err)
+		}
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
+		defer cancel()
+		stderr, err := dockerExec(ctx, nil, f, "cp", cid+":/vol/.", "-")
+		closeErr := f.Close()
+		if err != nil {
+			os.Remove(tarPath)
+			return fmt.Errorf("streaming volume %s: %s — %w", volName, stderr, err)
+		}
+		if closeErr != nil {
+			os.Remove(tarPath)
+			return fmt.Errorf("flushing %s: %w", tarPath, closeErr)
+		}
+		return nil
+	})
+}
+
+// exportVolumeData exports Docker named volumes for apps without HDD storage. v0.125.0: a
+// failed volume export is FATAL (export must never report success on a hollow bundle — the
+// pre-fix WARN+continue is exactly how the data-loss bundles were born).
+func (e *Exporter) exportVolumeData(stackName, dataDir string, manifest *Manifest) error {
 	volDir := filepath.Join(dataDir, "volumes")
 	os.MkdirAll(volDir, 0755)
 
@@ -608,28 +690,15 @@ func (e *Exporter) exportVolumeData(stackName, dataDir string, manifest *Manifes
 	e.debugf("Docker volumes for %s: %v (%d total)", stackName, volumes, len(volumes))
 	if len(volumes) == 0 {
 		e.debugf("no Docker volumes — skipping volume data export")
-		return
+		return nil
 	}
 
 	for _, volName := range volumes {
 		tarPath := filepath.Join(volDir, volName+".tar")
-		e.debugf("exporting volume %s via docker run alpine tar...", volName)
+		e.debugf("exporting volume %s via docker cp streaming...", volName)
 		volStart := time.Now()
-
-		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
-		cmd := exec.CommandContext(ctx, "docker", "run", "--rm",
-			"-v", volName+":/vol:ro",
-			"-v", volDir+":/out",
-			"alpine", "tar", "cf", "/out/"+volName+".tar", "-C", "/vol", ".")
-		out, err := cmd.CombinedOutput()
-		cancel()
-
-		if err != nil {
-			e.logger.Printf("[WARN] Export: volume %s export failed: %s — %v",
-				volName, strings.TrimSpace(string(out)), err)
-			e.debugf("volume %s export failed: %s", volName, strings.TrimSpace(string(out)))
-			os.Remove(tarPath)
-			continue
+		if err := e.exportVolumeTar(volName, tarPath); err != nil {
+			return fmt.Errorf("volume %s export failed: %w", volName, err)
 		}
 		if info, _ := os.Stat(tarPath); info != nil {
 			e.debugf("volume %s exported: %s in %v", volName, humanizeBytes(info.Size()), time.Since(volStart))
@@ -637,6 +706,27 @@ func (e *Exporter) exportVolumeData(stackName, dataDir string, manifest *Manifes
 		manifest.VolumeNames = append(manifest.VolumeNames, volName)
 	}
 	manifest.HasVolumeData = len(manifest.VolumeNames) > 0
+	return nil
+}
+
+// assertBundleDataComplete is the fail-loud post-export guard (v0.125.0, scenario B): every
+// manifest-CLAIMED data tar must exist non-empty in the staging tree before packaging. A
+// mismatch aborts the export — yesterday's outcome ("success" with a hollow bundle) is the
+// one this exists to make impossible.
+func assertBundleDataComplete(tmpDir string, manifest *Manifest) error {
+	for _, v := range manifest.VolumeNames {
+		fi, err := os.Stat(filepath.Join(tmpDir, "data", "volumes", v+".tar"))
+		if err != nil || fi.Size() == 0 {
+			return fmt.Errorf("bundle assertion: volume %q is claimed by the manifest but its tar is missing or empty", v)
+		}
+	}
+	for _, s := range manifest.HDDSubdirs {
+		fi, err := os.Stat(filepath.Join(tmpDir, "data", "hdd", s+".tar"))
+		if err != nil || fi.Size() == 0 {
+			return fmt.Errorf("bundle assertion: HDD subdir %q is claimed by the manifest but its tar is missing or empty", s)
+		}
+	}
+	return nil
 }
 
 // createTarGz creates a gzipped tar archive of a directory.

controller/internal/appexport/restore.go

@@ -326,6 +326,16 @@ func (e *Exporter) executeImport(req ImportRequest, job *Job) {
 	job.mu.Unlock()
 
 	e.logger.Printf("[INFO] Import: opening bundle for %s (%s)", manifest.AppName, manifest.DisplayName)
+
+	// v0.125.0 validate-before-destroy (scenario C): every manifest-claimed data tar must be
+	// present and non-empty BEFORE the app is stopped and BEFORE any volume is removed. Hollow
+	// bundles (a containerized v<=0.124.0 exporter stranded the tars host-side) land HERE — the
+	// pre-fix order wiped the volumes first and only then discovered the emptiness.
+	if err := validateBundleData(tmpDir, manifest); err != nil {
+		e.failJob(job, step, fmt.Sprintf("A csomag hiányos — az importálás el sem indult, a meglévő alkalmazás érintetlen. (%v) A csomagot valószínűleg egy régebbi (≤0.124.0), konténerben futó vezérlő exportálta — készíts friss exportot.", err))
+		return
+	}
+
 	e.debugf("step 0 (open bundle) done in %v", time.Since(stepStart))
 
 	job.setStep(step, "done", "")
@@ -597,9 +607,9 @@ func (e *Exporter) restoreHDDData(tmpDir string, manifest *Manifest, composePath
 		tarPath := filepath.Join(hddDir, subdir+".tar")
 		tarInfo, err := os.Stat(tarPath)
 		if err != nil {
-			e.logger.Printf("[WARN] Import: HDD tar not found: %s", tarPath)
-			e.debugf("restoreHDDData: tar not found: %s", tarPath)
-			continue
+			// v0.125.0: a claimed-but-absent tar is an ERROR (validateBundleData already refused
+			// it pre-destroy; this is defense in depth, not a reachable soft path).
+			return fmt.Errorf("HDD tar missing from bundle: %s", subdir+".tar")
 		}
 		e.debugf("restoreHDDData: subdir=%s tarSize=%s", subdir, humanizeBytes(tarInfo.Size()))
 
@@ -670,7 +680,52 @@ func resolveHDDMounts(composePath string, env map[string]string) []string {
 	return mounts
 }
 
-// restoreVolumeData recreates Docker named volumes from bundle tarballs.
+// validateBundleData asserts every manifest-claimed data tar exists non-empty in the extracted
+// bundle (v0.125.0, scenario C). Pure read — called before ANY destructive import step.
+func validateBundleData(tmpDir string, manifest *Manifest) error {
+	for _, v := range manifest.VolumeNames {
+		if err := ValidateSegment("volume_name", v); err != nil {
+			return err
+		}
+		fi, err := os.Stat(filepath.Join(tmpDir, "data", "volumes", v+".tar"))
+		if err != nil || fi.Size() == 0 {
+			return fmt.Errorf("a(z) %q kötet adata hiányzik a csomagból", v)
+		}
+	}
+	for _, s := range manifest.HDDSubdirs {
+		if err := ValidateSegment("hdd_subdir", s); err != nil {
+			return err
+		}
+		fi, err := os.Stat(filepath.Join(tmpDir, "data", "hdd", s+".tar"))
+		if err != nil || fi.Size() == 0 {
+			return fmt.Errorf("a(z) %q adatkönyvtár tartalma hiányzik a csomagból", s)
+		}
+	}
+	return nil
+}
+
+// importVolumeTar streams tarPath into the (existing) volume via `docker cp - <cid>:/vol` —
+// zero shared paths, correct on bare metal AND under the containerized controller (the
+// docker-run -v population was the v0.124.0 strand's import half).
+func (e *Exporter) importVolumeTar(volName, tarPath string) error {
+	return e.withVolumeHelper(volName, func(cid string) error {
+		f, err := os.Open(tarPath)
+		if err != nil {
+			return fmt.Errorf("opening %s: %w", tarPath, err)
+		}
+		defer f.Close()
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
+		defer cancel()
+		if stderr, err := dockerExec(ctx, f, nil, "cp", "-", cid+":/vol"); err != nil {
+			return fmt.Errorf("streaming into volume %s: %s — %w", volName, stderr, err)
+		}
+		return nil
+	})
+}
+
+// restoreVolumeData recreates Docker named volumes from bundle tarballs. v0.125.0: a missing
+// tar is an ERROR (defense in depth behind validateBundleData), and population streams via
+// docker cp instead of a docker-run -v host mount.
 func (e *Exporter) restoreVolumeData(tmpDir string, manifest *Manifest) error {
 	volDir := filepath.Join(tmpDir, "data", "volumes")
 
@@ -683,34 +738,24 @@ func (e *Exporter) restoreVolumeData(tmpDir string, manifest *Manifest) error {
 		tarPath := filepath.Join(volDir, volName+".tar")
 		tarInfo, err := os.Stat(tarPath)
 		if err != nil {
-			e.logger.Printf("[WARN] Import: volume tar not found: %s", tarPath)
-			e.debugf("restoreVolumeData: tar not found: %s", tarPath)
-			continue
+			return fmt.Errorf("volume tar missing from bundle: %s", volName+".tar")
 		}
 		e.debugf("restoreVolumeData: volume=%s tarSize=%s", volName, humanizeBytes(tarInfo.Size()))
 
 		// Create the Docker volume
 		e.debugf("restoreVolumeData: creating docker volume %s", volName)
 		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
-		out, err := exec.CommandContext(ctx, "docker", "volume", "create", volName).CombinedOutput()
+		stderr, err := dockerExec(ctx, nil, nil, "volume", "create", volName)
 		cancel()
 		if err != nil {
-			return fmt.Errorf("creating volume %s: %s — %w", volName, strings.TrimSpace(string(out)), err)
+			return fmt.Errorf("creating volume %s: %s — %w", volName, stderr, err)
 		}
-		e.debugf("restoreVolumeData: volume %s created: %s", volName, strings.TrimSpace(string(out)))
 
-		// Populate volume from tar
+		// Populate volume from tar (docker cp streaming)
 		e.logger.Printf("[INFO] Import: populating volume %s", volName)
-		e.debugf("restoreVolumeData: populating %s via docker run alpine tar xf...", volName)
 		popStart := time.Now()
-		ctx, cancel = context.WithTimeout(context.Background(), 10*time.Minute)
-		out, err = exec.CommandContext(ctx, "docker", "run", "--rm",
-			"-v", volName+":/vol",
-			"-v", volDir+":/in:ro",
-			"alpine", "tar", "xf", "/in/"+volName+".tar", "-C", "/vol").CombinedOutput()
-		cancel()
-		if err != nil {
-			return fmt.Errorf("populating volume %s: %s — %w", volName, strings.TrimSpace(string(out)), err)
+		if err := e.importVolumeTar(volName, tarPath); err != nil {
+			return fmt.Errorf("populating volume %s: %w", volName, err)
 		}
 		e.debugf("restoreVolumeData: volume %s populated in %v", volName, time.Since(popStart))
 	}

controller/internal/appexport/roundtrip_test.go

@@ -22,7 +22,11 @@ type rtProvider struct {
 	stackDir  string
 	stacksDir string
 	deployed  bool
+	running   bool
+	volumes   []string
 	started   bool
+	stopped   int
+	removed   int
 	savedEnv  map[string]string
 }
 
@@ -32,17 +36,17 @@ func (p *rtProvider) GetStackComposePath(string) (string, bool) {
 }
 func (p *rtProvider) GetStackHDDMounts(string) []string          { return nil }
 func (p *rtProvider) GetStackHDDPath(string) string              { return "" }
-func (p *rtProvider) IsStackRunning(string) bool                 { return false }
-func (p *rtProvider) StopStack(string) error                     { return nil }
+func (p *rtProvider) IsStackRunning(string) bool                 { return p.running }
+func (p *rtProvider) StopStack(string) error                     { p.stopped++; return nil }
 func (p *rtProvider) StartStack(string) error                    { p.started = true; return nil }
 func (p *rtProvider) GetStackDisplayName(n string) string        { return "RT " + n }
 func (p *rtProvider) GetStackNeedsHDD(string) bool               { return false }
-func (p *rtProvider) GetDockerVolumes(string) []string           { return nil }
+func (p *rtProvider) GetDockerVolumes(string) []string           { return p.volumes }
 func (p *rtProvider) IsStackDeployed(string) bool                { return p.deployed }
 func (p *rtProvider) GetDecryptedEnv(string) map[string]string   { return nil }
 func (p *rtProvider) GetStacksBaseDir() string                   { return p.stacksDir }
 func (p *rtProvider) RefreshStacks() error                       { return nil }
-func (p *rtProvider) RemoveStackVolumes(string) error            { return nil }
+func (p *rtProvider) RemoveStackVolumes(string) error            { p.removed++; return nil }
 func (p *rtProvider) SaveEncryptedAppConfig(stackDir string, env map[string]string) error {
 	p.savedEnv = env
 	return nil

controller/internal/appexport/volume_guard_test.go

@@ -0,0 +1,234 @@
+package appexport
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"testing"
+)
+
+// v0.125.0 — the containerized-.fab volume-strand fix (IA finding 1, HIGH). These tests pin:
+// (B) export can no longer lie — a stranded/empty tar aborts the export, no bundle;
+// (C) import validates BEFORE it destroys — a hollow bundle is refused with the app untouched;
+// the docker-cp command construction (image, mount shape, cp direction) and the always-remove
+// helper-container rule. The real docker legs are covered by the §3 live probe + §13 round-trip.
+
+// dockerCall records one dockerExec invocation.
+type dockerCall struct {
+	args  []string
+	stdin bool
+}
+
+// swapDockerExec installs a scripted fake for the package seam and restores it on cleanup.
+func swapDockerExec(t *testing.T, fn func(call dockerCall, stdin io.Reader, stdout io.Writer) (string, error)) *[]dockerCall {
+	t.Helper()
+	var mu sync.Mutex
+	calls := &[]dockerCall{}
+	orig := dockerExec
+	dockerExec = func(ctx context.Context, stdin io.Reader, stdout io.Writer, args ...string) (string, error) {
+		mu.Lock()
+		c := dockerCall{args: append([]string{}, args...), stdin: stdin != nil}
+		*calls = append(*calls, c)
+		mu.Unlock()
+		return fn(c, stdin, stdout)
+	}
+	t.Cleanup(func() { dockerExec = orig })
+	return calls
+}
+
+func volTestExporter(t *testing.T, volumes []string) (*Exporter, *rtProvider, string) {
+	t.Helper()
+	srcStack := t.TempDir()
+	os.WriteFile(filepath.Join(srcStack, "docker-compose.yml"), []byte("services:\n  vol-app:\n    image: alpine\n"), 0644)
+	prov := &rtProvider{stackDir: srcStack, stacksDir: t.TempDir(), deployed: true, volumes: volumes}
+	drive := t.TempDir()
+	return NewExporter(prov, log.New(io.Discard, "", 0), "test"), prov, drive
+}
+
+// Scenario B: a volume tar that fails to materialize (cp "succeeds" but writes nothing — the
+// strand's signature) must FAIL the export with the volume named, and NO bundle may exist.
+// Red-proof: remove the assertBundleDataComplete call → this test fails (hollow success).
+func TestExport_HollowVolumeTarAbortsExport(t *testing.T) {
+	swapDockerExec(t, func(c dockerCall, stdin io.Reader, stdout io.Writer) (string, error) {
+		switch c.args[0] {
+		case "create":
+			fmt.Fprint(stdout, "cid-123\n")
+			return "", nil
+		case "cp":
+			return "", nil // writes NOTHING to stdout — the stranded-tar signature
+		case "rm":
+			return "", nil
+		}
+		return "", fmt.Errorf("unexpected docker call: %v", c.args)
+	})
+
+	e, _, drive := volTestExporter(t, []string{"vol1"})
+	if err := e.StartExport(ExportRequest{StackName: "vol-app", DestDrive: drive}); err != nil {
+		t.Fatalf("StartExport: %v", err)
+	}
+	job := waitJob(t, e)
+	msg := jobErr(job)
+	if msg == "" {
+		t.Fatal("a hollow volume tar must FAIL the export — got success")
+	}
+	if !strings.Contains(msg, "vol1") {
+		t.Errorf("the error must NAME the missing volume, got %q", msg)
+	}
+	entries, _ := os.ReadDir(ExportDir(drive))
+	for _, en := range entries {
+		if strings.HasSuffix(en.Name(), ".fab") {
+			t.Fatalf("a bundle was produced despite the hollow tar: %s", en.Name())
+		}
+	}
+}
+
+// Scenario C: a bundle whose manifest claims a volume without its tar is refused BEFORE any
+// destructive step — the app is not stopped, no volume is removed or recreated, zero docker
+// calls happen. Red-proof: disable the pre-flight (pre-fix order: wipe first, discover later)
+// → the zero-destruction assertions fail.
+func TestImport_HollowBundleRefusedBeforeDestroy(t *testing.T) {
+	calls := swapDockerExec(t, func(c dockerCall, stdin io.Reader, stdout io.Writer) (string, error) {
+		return "", nil
+	})
+
+	// Handcraft a hollow bundle: manifest CLAIMS volume data, data/volumes is empty.
+	tree := t.TempDir()
+	os.MkdirAll(filepath.Join(tree, "config"), 0755)
+	os.MkdirAll(filepath.Join(tree, "data", "volumes"), 0755)
+	os.WriteFile(filepath.Join(tree, "config", "docker-compose.yml"), []byte("services: {}\n"), 0644)
+	man := &Manifest{
+		Version: ManifestVersion, AppName: "vol-app", DisplayName: "Vol App",
+		HasVolumeData: true, VolumeNames: []string{"vol1"},
+		ConfigFiles: []string{"docker-compose.yml"},
+	}
+	data, err := man.Marshal()
+	if err != nil {
+		t.Fatal(err)
+	}
+	os.WriteFile(filepath.Join(tree, "manifest.json"), data, 0644)
+	fab := filepath.Join(t.TempDir(), "hollow.fab")
+	if err := createTarGz(fab, tree); err != nil {
+		t.Fatalf("createTarGz: %v", err)
+	}
+
+	prov := &rtProvider{stackDir: t.TempDir(), stacksDir: t.TempDir(), deployed: true, running: true}
+	e := NewExporter(prov, log.New(io.Discard, "", 0), "test")
+	if err := e.StartImport(ImportRequest{FABPath: fab}); err != nil {
+		t.Fatalf("StartImport: %v", err)
+	}
+	job := waitJob(t, e)
+	msg := jobErr(job)
+	if msg == "" {
+		t.Fatal("a hollow bundle must be REFUSED — got success")
+	}
+	if !strings.Contains(msg, "érintetlen") {
+		t.Errorf("refusal copy must state the app is untouched, got %q", msg)
+	}
+	// THE exact non-effects: nothing was stopped, wiped, recreated or started.
+	if prov.stopped != 0 || prov.removed != 0 {
+		t.Fatalf("refusal happened AFTER destruction: stopped=%d removedVolumes=%d", prov.stopped, prov.removed)
+	}
+	if prov.started {
+		t.Fatal("a refused import must not start the app")
+	}
+	if len(*calls) != 0 {
+		t.Fatalf("a refused import must make ZERO docker calls, got %v", *calls)
+	}
+}
+
+// Command construction + helper hygiene: the export leg uses create/cp/rm with the exact arg
+// shapes the §3 probe validated, and the helper container is force-removed EVEN when cp fails.
+func TestExportVolumeTar_CommandShapesAndHelperCleanup(t *testing.T) {
+	t.Run("happy path shapes", func(t *testing.T) {
+		calls := swapDockerExec(t, func(c dockerCall, stdin io.Reader, stdout io.Writer) (string, error) {
+			switch c.args[0] {
+			case "create":
+				fmt.Fprint(stdout, "cid-abc\n")
+			case "cp":
+				fmt.Fprint(stdout, "TARBYTES")
+			}
+			return "", nil
+		})
+		e, _, _ := volTestExporter(t, nil)
+		tarPath := filepath.Join(t.TempDir(), "v.tar")
+		if err := e.exportVolumeTar("vol1", tarPath); err != nil {
+			t.Fatalf("exportVolumeTar: %v", err)
+		}
+		got, _ := os.ReadFile(tarPath)
+		if string(got) != "TARBYTES" {
+			t.Fatalf("tar content = %q", got)
+		}
+		want := [][]string{
+			{"create", "-v", "vol1:/vol", "alpine", "true"},
+			{"cp", "cid-abc:/vol/.", "-"},
+			{"rm", "-f", "cid-abc"},
+		}
+		assertCalls(t, *calls, want)
+	})
+
+	t.Run("helper removed on cp failure", func(t *testing.T) {
+		calls := swapDockerExec(t, func(c dockerCall, stdin io.Reader, stdout io.Writer) (string, error) {
+			switch c.args[0] {
+			case "create":
+				fmt.Fprint(stdout, "cid-err\n")
+				return "", nil
+			case "cp":
+				return "boom", fmt.Errorf("cp failed")
+			}
+			return "", nil
+		})
+		e, _, _ := volTestExporter(t, nil)
+		tarPath := filepath.Join(t.TempDir(), "v.tar")
+		if err := e.exportVolumeTar("vol1", tarPath); err == nil {
+			t.Fatal("cp failure must surface")
+		}
+		if _, err := os.Stat(tarPath); !os.IsNotExist(err) {
+			t.Error("a failed export must not leave a partial tar")
+		}
+		last := (*calls)[len(*calls)-1]
+		if strings.Join(last.args, " ") != "rm -f cid-err" {
+			t.Fatalf("helper container must be force-removed on failure, last call: %v", last.args)
+		}
+	})
+
+	t.Run("import leg shapes", func(t *testing.T) {
+		calls := swapDockerExec(t, func(c dockerCall, stdin io.Reader, stdout io.Writer) (string, error) {
+			if c.args[0] == "create" {
+				fmt.Fprint(stdout, "cid-imp\n")
+			}
+			if c.args[0] == "cp" && !c.stdin {
+				t.Error("import cp must stream the tar on stdin")
+			}
+			return "", nil
+		})
+		e, _, _ := volTestExporter(t, nil)
+		tarPath := filepath.Join(t.TempDir(), "v.tar")
+		os.WriteFile(tarPath, []byte("TAR"), 0644)
+		if err := e.importVolumeTar("vol1", tarPath); err != nil {
+			t.Fatalf("importVolumeTar: %v", err)
+		}
+		want := [][]string{
+			{"create", "-v", "vol1:/vol", "alpine", "true"},
+			{"cp", "-", "cid-imp:/vol"},
+			{"rm", "-f", "cid-imp"},
+		}
+		assertCalls(t, *calls, want)
+	})
+}
+
+func assertCalls(t *testing.T, got []dockerCall, want [][]string) {
+	t.Helper()
+	if len(got) != len(want) {
+		t.Fatalf("docker calls = %d, want %d (%v)", len(got), len(want), got)
+	}
+	for i := range want {
+		if strings.Join(got[i].args, " ") != strings.Join(want[i], " ") {
+			t.Errorf("call %d = %v, want %v", i, got[i].args, want[i])
+		}
+	}
+}