In order to avoid unnecessary operations, the `update-preview-server.sh`
script, that is used to update the PR preview server Docker container,
will only try to update the Docker container if either any files in the
`aio/aio-builds-setup/` directory have changed since the last update or
if a previous update failed. A failed previous update is detected by
checking whether the temporary `aio-builds:provisional` Docker image
still exists. This temporary image is created during the update
operation and is renamed to `aio-builds:latest` if the update goes well.
Previously, the update script was not able to detect a previous failed
attempt if the operation failed before creating the
`aio-builds:provisional` Docker image, such as if the `create-image.sh`
script failed. This could lead to a situation where the preview server
Docker container would not be updated after a failed attempt.
This commit improves the logic for detecting failed attempts to account
for this type of failures. It does this by not removing an older
`aio-builds:provisional` Docker image until a new one is successfully
created.
NOTE: While this is not full-proof, it is an improvement as it
eliminates a certain kind of failures.
PR Close#37015
fcb68cc139