tag_build.sh: improve handling of race condition

While reviewing our nightly tagging script, I noticed a potential race condition (which we have never observed so far). Make the script more robust for the very unlikely case that two builds try to create the same nightly tag from a different commit (could in theory happen if the release coordinator merges something around the nightly deadline).

Also use show-ref instead of rev-parse to check for tags and some other minor cleanups, i.e. remove unused support of specifying tag names via the $datestamp environment variable (our Jenkins jobs always call this script with the explicit -d argument).

Bringing this to the attention of @aundrus and @tsulaia in case there are any unforeseen side-effects for the next nightly builds.

Once validated in main will also request this for 24.0.

marked this merge request as ready

changed the description

This merge request affects 1 package:

• Build

This merge request affects 1 file:

• Build/AtlasBuildScripts/tag_build.sh

Adding @akraszna as watcher

added Build main review-pending-level-1 labels

changed the description

CI Result SUCCESS (hash 18042207)

	Athena	AthSimulation	AthGeneration	AnalysisBase	AthAnalysis	DetCommon
externals
cmake
make
tests

Full details available on this CI monitor view. Check the JIRA CI status board for known problems
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 0
DetCommon: number of compilation errors 0, warnings 0
For experts only: Jenkins output (remote access info)

removed review-pending-level-1 label

added review-approved label

merged

mentioned in commit d193eec3

No side effects have been observed in nightly jobs so far. Nightly tags have been added to GitLab at the usual pace. Thanks to @fwinkl for addressing potentially dangerous race conditions, even when the likelihood is low.