Unable to download blob snapshot with a name starting with whitespace

[craxal]

Storage Explorer Version: 1.13.0
Build Number: dev
Platform/OS: Windows 10
Architecture: i86
Regression From: N/A

Bug Description

I am unable to download a single snapshot of a blob whose name starts with whitespace.

Example: " space.txt"

Steps to Reproduce

1. Launch Storage Explorer and open a standard (non-HNS enabled) blob container.
2. Create a local file from the command line with a space at the beginning of the name:

   New-Item " space.txt"

3. Upload the file create in step 3.
4. Create one or two snapshots of the uploaded blob.
5. Select the uploaded blob and click Manage Snapshots.
6. Select one of the snapshots and click Download. Select a location to download the snapshot.

Expected Experience

The snapshot downloads successfully.

Actual Experience

The following error message appears in the Activity Log:

Failed to start transfer: Multi-snapshot download is currently not supported.

Additional Context

The error is caused by this line of code in "DownloadBlobs.ts":

let noUnsafeNameIssue = os.platform() !== "win32" || WindowsSafeFileName.isPathSafe(blobs[0].name);

A regular expression in isPathSafe is used to test whether blob names are safe to download to a Windows file system. However, the regular expression erroneously disallows whitespace at the beginning of file names.

At the very least, the error presented is misleading. We should have separate error messages depending on the condition that's violated.