From 35ac37313d02f1254269ab9b5311f1a58523d8a3 Mon Sep 17 00:00:00 2001
From: Abin Simon <abinsimon10@gmail.com>
Date: Mon, 8 Jan 2024 16:41:02 +0530
Subject: [PATCH] Return proper error when backups are empty for details
 command (#4968)

<!-- PR description-->

---

#### Does this PR need a docs update or release note?

- [x] :white_check_mark: Yes, it's included
- [ ] :clock1: Yes, but in a later PR
- [ ] :no_entry: No

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] :sunflower: Feature
- [ ] :bug: Bugfix
- [ ] :world_map: Documentation
- [ ] :robot: Supportability/Tests
- [ ] :computer: CI/Deployment
- [x] :broom: Tech Debt/Cleanup

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

#### Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] :muscle: Manual
- [x] :zap: Unit test
- [ ] :green_heart: E2E
---
 CHANGELOG.md                  |  3 +++
 src/cli/backup/backup.go      |  6 ++++++
 src/cli/backup/backup_test.go | 29 +++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 96153f31d..d4cb9534d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased] (beta)
 
+### Changed
+- When running `backup details` on an empty backup returns a more helpful error message.
+
 ## [v0.18.0] (beta) - 2024-01-02
 
 ### Fixed
diff --git a/src/cli/backup/backup.go b/src/cli/backup/backup.go
index fa22396b9..c95d5803d 100644
--- a/src/cli/backup/backup.go
+++ b/src/cli/backup/backup.go
@@ -28,6 +28,8 @@ import (
 	"github.com/alcionai/corso/src/pkg/store"
 )
 
+var ErrEmptyBackup = clues.New("no items in backup")
+
 // ---------------------------------------------------------------------------
 // adding commands to cobra
 // ---------------------------------------------------------------------------
@@ -394,6 +396,10 @@ func genericDetailsCore(
 		return nil, clues.Wrap(errs.Failure(), "Failed to get backup details in the repository")
 	}
 
+	if len(d.Entries) == 0 {
+		return nil, ErrEmptyBackup
+	}
+
 	if opts.SkipReduce {
 		return d, nil
 	}
diff --git a/src/cli/backup/backup_test.go b/src/cli/backup/backup_test.go
index 4d70702ae..c33cae150 100644
--- a/src/cli/backup/backup_test.go
+++ b/src/cli/backup/backup_test.go
@@ -5,10 +5,12 @@ import (
 
 	"github.com/alcionai/clues"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 
 	"github.com/alcionai/corso/src/cli/utils/testdata"
 	"github.com/alcionai/corso/src/internal/tester"
+	"github.com/alcionai/corso/src/pkg/backup/details"
 	dtd "github.com/alcionai/corso/src/pkg/backup/details/testdata"
 	"github.com/alcionai/corso/src/pkg/control"
 	"github.com/alcionai/corso/src/pkg/path"
@@ -66,3 +68,30 @@ func (suite *BackupUnitSuite) TestGenericDetailsCore() {
 	assert.NoError(t, err, clues.ToCore(err))
 	assert.ElementsMatch(t, expected, output.Entries)
 }
+
+func (suite *BackupUnitSuite) TestGenericDetailsCore_empty() {
+	t := suite.T()
+
+	ctx, flush := tester.NewContext(t)
+	defer flush()
+
+	bg := testdata.VersionedBackupGetter{
+		Details: &details.Details{
+			DetailsModel: details.DetailsModel{
+				Entries: []details.Entry{},
+			},
+		},
+	}
+
+	sel := selectors.NewExchangeBackup([]string{"user-id"})
+	sel.Include(sel.AllData())
+
+	_, err := genericDetailsCore(
+		ctx,
+		bg,
+		"backup-ID",
+		sel.Selector,
+		control.DefaultOptions())
+	require.Error(t, err, "has error")
+	assert.ErrorIs(t, err, ErrEmptyBackup, clues.ToCore(err))
+}