Code change:
defaultVersion := cmdutil.OutputVersion(cmd, clientConfig.Version) results := editResults{} for { <del> obj, err := resource.AsVersionedObject(infos, false, defaultVersion) </del> <ins> objs, err := resource.AsVersionedObjects(infos, defaultVersion) </ins> if err != nil { return preservedFile(err, results.file, out) } <ins> // if input object is a list, traverse and edit each item one at a time for _, obj := range objs { // TODO: add an annotating YAML printer that can print inline comments on each field, //   including descriptions or validation errors // generate the file to edit buf := &bytes.Buffer{} if err := results.header.writeTo(buf); err != nil { return preservedFile(err, results.file, out) } if err := printer.PrintObj(obj, buf); err != nil { return preservedFile(err, results.file, out) } original := buf.Bytes() </ins> <del> // TODO: add an annotating YAML printer that can print inline comments on each field, //   including descriptions or validation errors // generate the file to edit buf := &bytes.Buffer{} if err := results.header.writeTo(buf); err != nil { return preservedFile(err, results.file, out) } if err := printer.PrintObj(obj, buf); err != nil { return preservedFile(err, results.file, out) } original := buf.Bytes() // launch the editor edit := editor.NewDefaultEditor() edited, file, err := edit.LaunchTempFile("kubectl-edit-", ext, buf) if err != nil { return preservedFile(err, results.file, out) } </del> <ins> // launch the editor edit := editor.NewDefaultEditor() edited, file, err := edit.LaunchTempFile("kubectl-edit-", ext, buf) if err != nil { return preservedFile(err, results.file, out) } </ins> <del> // cleanup any file from the previous pass if len(results.file) > 0 { os.Remove(results.file) } </del> <ins> // cleanup any file from the previous pass if len(results.file) > 0 { os.Remove(results.file) } </ins> <del> glog.V(4).Infof("User edited:n%s", string(edited)) fmt.Printf("User edited:n%s", string(edited)) lines, err := hasLines(bytes.NewBuffer(edited)) if err != nil { return preservedFile(err, file, out) } if bytes.Equal(original, edited) { if len(results.edit) > 0 { preservedFile(nil, file, out) } else { os.Remove(file) </del> <ins> glog.V(4).Infof("User edited:n%s", string(edited)) lines, err := hasLines(bytes.NewBuffer(edited)) if err != nil { return preservedFile(err, file, out) </ins> } <del> fmt.Fprintln(out, "Edit cancelled, no changes made.") return nil } if !lines { if len(results.edit) > 0 { preservedFile(nil, file, out) } else { os.Remove(file) </del> <ins> // Compare content without comments if bytes.Equal(stripComments(original), stripComments(edited)) { if len(results.edit) > 0 { preservedFile(nil, file, out) } else { os.Remove(file) } fmt.Fprintln(out, "Edit cancelled, no changes made.") continue } if !lines { if len(results.edit) > 0 { preservedFile(nil, file, out) } else { os.Remove(file) } fmt.Fprintln(out, "Edit cancelled, saved file was empty.") continue </ins> } <del> fmt.Fprintln(out, "Edit cancelled, saved file was empty.") return nil } results = editResults{ file: file, } </del> <ins> results = editResults{ file: file, } </ins> <del> // parse the edited file updates, err := rmap.InfoForData(edited, "edited-file") if err != nil { return preservedFile(err, file, out) } </del> <ins> // parse the edited file updates, err := rmap.InfoForData(edited, "edited-file") if err != nil { return fmt.Errorf("The edited file had a syntax error: %v", err) } </ins> <del> // annotate the edited object for kubectl apply if err := kubectl.UpdateApplyAnnotation(updates); err != nil { return preservedFile(err, file, out) } </del> <ins> // annotate the edited object for kubectl apply if err := kubectl.UpdateApplyAnnotation(updates); err != nil { return preservedFile(err, file, out) } </ins> <del> visitor := resource.NewFlattenListVisitor(updates, rmap) </del> <ins> visitor := resource.NewFlattenListVisitor(updates, rmap) </ins> <del> // need to make sure the original namespace wasn't changed while editing if err = visitor.Visit(resource.RequireNamespace(cmdNamespace)); err != nil { return preservedFile(err, file, out) } </del> <ins> // need to make sure the original namespace wasn't changed while editing if err = visitor.Visit(resource.RequireNamespace(cmdNamespace)); err != nil { return preservedFile(err, file, out) } </ins> <del> // use strategic merge to create a patch originalJS, err := yaml.ToJSON(original) if err != nil { return preservedFile(err, file, out) } editedJS, err := yaml.ToJSON(edited) if err != nil { return preservedFile(err, file, out) } patch, err := strategicpatch.CreateStrategicMergePatch(originalJS, editedJS, obj) // TODO: change all jsonmerge to strategicpatch // for checking preconditions preconditions := []jsonmerge.PreconditionFunc{} if err != nil { glog.V(4).Infof("Unable to calculate diff, no merge is possible: %v", err) return preservedFile(err, file, out) } else { preconditions = append(preconditions, jsonmerge.RequireKeyUnchanged("apiVersion")) preconditions = append(preconditions, jsonmerge.RequireKeyUnchanged("kind")) preconditions = append(preconditions, jsonmerge.RequireMetadataKeyUnchanged("name")) results.version = defaultVersion } </del> <ins> // use strategic merge to create a patch originalJS, err := yaml.ToJSON(original) if err != nil { return preservedFile(err, file, out) } editedJS, err := yaml.ToJSON(edited) if err != nil { return preservedFile(err, file, out) } patch, err := strategicpatch.CreateStrategicMergePatch(originalJS, editedJS, obj) // TODO: change all jsonmerge to strategicpatch // for checking preconditions preconditions := []jsonmerge.PreconditionFunc{} if err != nil { glog.V(4).Infof("Unable to calculate diff, no merge is possible: %v", err) return preservedFile(err, file, out) } else { preconditions = append(preconditions, jsonmerge.RequireKeyUnchanged("apiVersion")) preconditions = append(preconditions, jsonmerge.RequireKeyUnchanged("kind")) preconditions = append(preconditions, jsonmerge.RequireMetadataKeyUnchanged("name")) results.version = defaultVersion } </ins> <del> if hold, msg := jsonmerge.TestPreconditionsHold(patch, preconditions); !hold { fmt.Fprintf(out, "error: %s", msg) return preservedFile(nil, file, out) } </del> <ins> if hold, msg := jsonmerge.TestPreconditionsHold(patch, preconditions); !hold { fmt.Fprintf(out, "error: %s", msg) return preservedFile(nil, file, out) } </ins> <del> err = visitor.Visit(func(info *resource.Info, err error) error { patched, err := resource.NewHelper(info.Client, info.Mapping).Patch(info.Namespace, info.Name, api.StrategicMergePatchType, patch) if err != nil { fmt.Fprintln(out, results.addError(err, info)) </del> <ins> err = visitor.Visit(func(info *resource.Info, err error) error { patched, err := resource.NewHelper(info.Client, info.Mapping).Patch(info.Namespace, info.Name, api.StrategicMergePatchType, patch) if err != nil { fmt.Fprintln(out, results.addError(err, info)) return nil } info.Refresh(patched, true) cmdutil.PrintSuccess(mapper, false, out, info.Mapping.Resource, info.Name, "edited") </ins> return nil <ins> }) if err != nil { return preservedFile(err, file, out) </ins> } <del> info.Refresh(patched, true) cmdutil.PrintSuccess(mapper, false, out, info.Mapping.Resource, info.Name, "edited") return nil }) if err != nil { return preservedFile(err, file, out) } if results.retryable > 0 { fmt.Fprintf(out, "You can run `kubectl replace -f %s` to try this update again.n", file) return errExit } if results.conflict > 0 { fmt.Fprintf(out, "You must update your local resource version and run `kubectl replace -f %s` to overwrite the remote changes.n", file) return errExit </del> <ins> if results.retryable > 0 { fmt.Fprintf(out, "You can run `kubectl replace -f %s` to try this update again.n", file) return errExit } if results.conflict > 0 { fmt.Fprintf(out, "You must update your local resource version and run `kubectl replace -f %s` to overwrite the remote changes.n", file) return errExit } if len(results.edit) == 0 { if results.notfound == 0 { os.Remove(file) } else { fmt.Fprintf(out, "The edits you made on deleted resources have been saved to %qn", file) } } </ins> } if len(results.edit) == 0 { <del> if results.notfound == 0 { os.Remove(file) } else { fmt.Fprintf(out, "The edits you made on deleted resources have been saved to %qn", file) } </del> return nil }

Related discussion:
text: When trying to edit multiple resources, for example: will panic. Ref as the possible cause cc
if was the cause, any fix needs to happen in 1.1 as well, was already cherry picked there
Also shows that we need a test for this case.
is the cause. When we edit multiple resources (i.e., list-type objects), the list's Accessor.annotations (type ) is nil and will panic when UpdateApplyAnnotation tries to SetAnnotations ().