normalize bucket naming during config lookup (#1025)

## Description

Ensure s3 bucket name inputs are normalized
in all uses.  Currently, the normalized format is
applied when using storage, but not when passing
around --bucket flag values elsewhere.

## Type of change

- [x] 🐛 Bugfix

## Issue(s)

* #975

## Test Plan

- [x] 💪 Manual
- [x] ⚡ Unit test

src/cli/config/storage.go

@@ -57,6 +57,10 @@ func configureStorage(
 			return store, errors.Wrap(err, "reading s3 configs from corso config file")
 		}
 
+		if b, ok := overrides[storage.Bucket]; ok {
+			overrides[storage.Bucket] = common.NormalizeBucket(b)
+		}
+
 		if err := mustMatchConfig(vpr, s3Overrides(overrides)); err != nil {
 			return store, errors.Wrap(err, "verifying s3 configs in corso config file")
 		}

src/internal/common/buckets.go

@@ -0,0 +1,13 @@
+package common
+
+import "strings"
+
+// NormalizeBuckets ensures that bucket names are cleaned and
+// standardized according to the downstream needs of minio.
+//
+// Any url prefixing to location the bucket (ex: s3://bckt)
+// will be removed, leaving only the bucket name (bckt).
+// Corso should only utilize or store the normalized name.
+func NormalizeBucket(b string) string {
+	return strings.TrimPrefix(b, "s3://")
+}

src/internal/common/buckets_test.go

@@ -0,0 +1,30 @@
+package common_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/suite"
+
+	"github.com/alcionai/corso/src/internal/common"
+)
+
+type CommonBucketsSuite struct {
+	suite.Suite
+	ctx context.Context
+}
+
+func TestCommonBucketsSuite(t *testing.T) {
+	suite.Run(t, new(CommonBucketsSuite))
+}
+
+func (suite *CommonBucketsSuite) TestDoesThings() {
+	t := suite.T()
+	trimmablePrefixes := []string{"s3://"}
+
+	for _, pfx := range trimmablePrefixes {
+		assert.Equal(t, "fnords", common.NormalizeBucket(pfx+"fnords"))
+		assert.Equal(t, "smarf", "smarf")
+	}
+}

src/pkg/storage/s3.go

@@ -1,9 +1,9 @@
 package storage
 
 import (
-	"strings"
-
 	"github.com/pkg/errors"
+
+	"github.com/alcionai/corso/src/internal/common"
 )
 
 type S3Config struct {
@@ -28,7 +28,7 @@ const (
 
 func (c S3Config) Normalize() S3Config {
 	return S3Config{
-		Bucket:   strings.TrimPrefix(c.Bucket, "s3://"),
+		Bucket:   common.NormalizeBucket(c.Bucket),
 		Endpoint: c.Endpoint,
 		Prefix:   c.Prefix,
 	}