sgdisk -e causes unintended GPT partition table creation

SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server for SAP Applications 15 SP6

Using sgdisk -e on a raw disk without an existing partitioning scheme unexpectedly creates a new GPT, potentially causing data loss.

This is expected and intended behavior. There is no separate "write" option in sgdisk, so any command that changes the partition table, including "-e", will cause it to write those changes to disk. As an alternative,  the "-P" ("--pretend") option can be used to prevent changes from being written to disk (this is not called out for each and every option).

Although the sgdisk man page does not explicitly state that a GPT will be created if none exists, this behavior is not unique to the "-e" option, other commands exhibit similar behavior. Therefore, documenting this behavior solely under the "-e" option would be misleading. Such cases are addressed by the general warning in the documentation [1]:

Warning: Not for Interactive Use

Using this option on a disk without an existing GPT can result in data loss, as it unconditionally writes a new GPT partition table, potentially destroying pre-existing structures such as LVM metadata.

Steps to reproduce:

1. Raw disk without a partition table on it:

sles15-sp6-clone:~ # parted -s /dev/vdb p 
Error: /dev/vdb: unrecognised disk label
Partition Table: unknown

2. Using sgdisk -e on that disk, produces:

sles15-sp6-clone:~ # sgdisk -e /dev/vdb
Creating new GPT entries in memory.
The operation has completed successfully.

3. Checking the disk again:

sles15-sp6-clone:~ # parted -s /dev/vdb p 
Partition Table: gpt

[1] https://www.rodsbooks.com/gdisk/sgdisk-walkthrough.html