From 56287c42fa30d6ddbbc186d70096f7c5b4593333 Mon Sep 17 00:00:00 2001
From: ashmrtn <ashmrtnz@alcion.ai>
Date: Mon, 3 Oct 2022 10:49:20 -0700
Subject: [PATCH] Skip kopia upload when no collections given (#846)

## Description

<!-- Insert PR description-->
Currently does not throw an error. Open to other suggestions on return values.

## Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] :sunflower: Feature
- [x] :bug: Bugfix
- [ ] :world_map: Documentation
- [ ] :robot: Test
- [ ] :computer: CI/Deployment
- [ ] :hamster: Trivial/Minor

## Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* closes #844
* #1000

## Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] :muscle: Manual
- [x] :zap: Unit test
- [ ] :green_heart: E2E
---
 src/internal/kopia/wrapper.go      |  4 ++++
 src/internal/kopia/wrapper_test.go | 28 ++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/src/internal/kopia/wrapper.go b/src/internal/kopia/wrapper.go
index dd2aae9e9..5801917aa 100644
--- a/src/internal/kopia/wrapper.go
+++ b/src/internal/kopia/wrapper.go
@@ -390,6 +390,10 @@ func (w Wrapper) BackupCollections(
 
 	defer trace.StartRegion(ctx, "kopia:backupCollections").End()
 
+	if len(collections) == 0 {
+		return &BackupStats{}, &details.Details{}, nil
+	}
+
 	progress := &corsoProgress{
 		pending: map[string]*itemDetails{},
 		deets:   &details.Details{},
diff --git a/src/internal/kopia/wrapper_test.go b/src/internal/kopia/wrapper_test.go
index 867672f73..7c960deb3 100644
--- a/src/internal/kopia/wrapper_test.go
+++ b/src/internal/kopia/wrapper_test.go
@@ -780,6 +780,34 @@ type backedupFile struct {
 	data       []byte
 }
 
+func (suite *KopiaIntegrationSuite) TestBackupCollectionsHandlesNoCollections() {
+	table := []struct {
+		name        string
+		collections []data.Collection
+	}{
+		{
+			name:        "NilCollections",
+			collections: nil,
+		},
+		{
+			name:        "EmptyCollections",
+			collections: []data.Collection{},
+		},
+	}
+
+	for _, test := range table {
+		suite.T().Run(test.name, func(t *testing.T) {
+			ctx := context.Background()
+
+			s, d, err := suite.w.BackupCollections(ctx, test.collections)
+			require.NoError(t, err)
+
+			assert.Equal(t, BackupStats{}, *s)
+			assert.Empty(t, d.Entries)
+		})
+	}
+}
+
 type KopiaSimpleRepoIntegrationSuite struct {
 	suite.Suite
 	w          *Wrapper