Configure nightly release pipeline to run only on schedule and skip when no changes

[Copilot]

This PR configures the Azure Pipeline nightly release to run efficiently by implementing two key behaviors:

1. Schedule-only execution: The pipeline now runs only on the scheduled cron (3 AM daily) and removes automatic triggering on code changes
2. Skip when no changes: Uses always: false to automatically skip scheduled runs when there are no new commits in the develop branch since the last execution

Pipeline Configuration

Updated .azure-pipelines/release/release-nightly.yml:

schedules:
  - cron: 0 3 * * *
    branches:
      include:
        - develop
    always: false

trigger: none

Coordination with Build Pipeline

The timing remains coordinated with the existing build pipeline:

• Build pipeline (vscode-gradle-nightly.yml): Runs at 2 AM and creates artifacts
• Release pipeline (release-nightly.yml): Runs at 3 AM and publishes artifacts

This ensures the build completes before the release pipeline attempts to download and publish artifacts, while avoiding unnecessary releases when no code changes have occurred.

Fixes #1705.

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[wenytang-ms]

@copilot Does this trigger mechanism guarantee that the pipeline will be executed during the current cron interval upon a PR merge or code change?

[Copilot]

@copilot Does this trigger mechanism guarantee that the pipeline will be executed during the current cron interval upon a PR merge or code change?

No, the trigger mechanism does not wait for the cron interval. With the current configuration:

When code is pushed to develop:

• The release pipeline runs immediately due to the trigger section
• It does NOT wait for the 3 AM scheduled time

Potential Issue:
The build pipeline (vscode-gradle-nightly.yml) only runs at 2 AM (has trigger: none), but the release pipeline now runs both:

1. At 3 AM (scheduled)
2. Immediately on code changes (trigger)

This means if code is pushed at 10 AM, the release pipeline will try to run immediately but may not find fresh artifacts since the build pipeline only ran at 2 AM.

Possible solutions:

1. Keep current behavior if you want immediate releases with potentially older artifacts
2. Remove the trigger section to only release on schedule after builds complete
3. Add triggers to the build pipeline as well to ensure fresh artifacts

Which behavior do you prefer for the nightly release pipeline?

[wenytang-ms]

@copilot please set the pipeline follow 2 rules below

1. only schedule release
2. if no code change in the schedule release, skip this schedule release

[Copilot]

@copilot please set the pipeline follow 2 rules below

1. only schedule release
2. if no code change in the schedule release, skip this schedule release

I've updated the pipeline configuration to follow both rules:

1. Only schedule release: Removed the trigger section and set trigger: none so the pipeline only runs on the scheduled cron (3 AM daily)
2. Skip if no code changes: Added always: false to the schedule configuration, which automatically skips the scheduled run when there are no new changes in the develop branch since the last execution

The pipeline will now only run at 3 AM daily and only when there have been code changes, ensuring efficient resource usage and avoiding unnecessary releases.

Changes in commit f0916a1.