[CI] Exclude doc files from CI to save CI time

[ueqri]

Added the exclude rules for push and PR triggers. So updates to doc, README, etc. won't cause the formatting + main CI to run.

[kunaltyagi]

This PR still runs the main CI for docs. Create a new issue for the docs or edit the existing issue to reflect the partially resolved state?

[ueqri]

This PR still runs the main CI for docs. Create a new issue for the docs or edit the existing issue to reflect the partially resolved state?

yeah, current CI build is still based on the old azure pipelines file in master. It will take effect after merging this PR.
Could I fix some small typo in pcl_style_guide I've found before to reflect the partially resolved state?

[kunaltyagi]

Can't rescind my review from mobile, hence this. Please ignore

Adding the rationale in a second review below

[ueqri]

I've implemented the new pipeline in .ci/docs-pipeline.yaml. If everything is ok, please add the pipeline in the Azure DevOps after merging. Thank you!

[ueqri]

I think the latest commit looks good now. Could you take a look again please?

[ueqri]

I admit that the method is kind of obscure and tricky now. I'd add git check to make it more legible and comprehensible.

[kunaltyagi]

Looks good.

@ueqri Could you do the following:

• Create a dummy project to show the CI runs (I believe you've already done this)
• Create a PR that runs only doc pipeline
• Create a PR that runs build then doc pipeline

[ueqri]

Looks good.

@ueqri Could you do the following:

* Create a dummy project to show the CI runs (I believe you've already done this)

* Create a PR that runs only doc pipeline

* Create a PR that runs build then doc pipeline

Of course:satisfied:, I will do it in my repository and paste the result here soon. Thank you:satisfied:!

[ueqri]

* Create a dummy project to show the CI runs (I believe you've already done this)

* Create a PR that runs only doc pipeline

* Create a PR that runs build then doc pipeline

I've made this in https://github.com/ueqri/pcl/tree/test-new-docs-pipeline, and related Azure pipelines dashboard are here: https://dev.azure.com/ueqri-ci/pcl-test/_build?view=runs

As I didn't set branch rules for triggers, some push beyond test-new-docs-pipeline branch also run CI and I canceled them immediately. So the result is a bit messy, I'm sorry for that.

The exactly related CI run are:

• PR that runs only doc pipeline: https://dev.azure.com/ueqri-ci/pcl-test/_build/results?buildId=108&view=results
• PR that runs build then doc pipeline:
  • build pipeline: https://dev.azure.com/ueqri-ci/pcl-test/_build/results?buildId=113&view=results
  • triggered docs pipeline: https://dev.azure.com/ueqri-ci/pcl-test/_build/results?buildId=114&view=results
    (name of triggered docs pipeline may be confused, but it does not matter, Automatically triggered by Pipeline Build-CI/20210410.23 in result summary shows the pipeline works correctly)

[kunaltyagi]

The sample links look good.

Just a few minor comments

[ueqri]

I'm gratitude to you for helping me and guiding me in this PR. Thank you! 😀

And I was wondering if this could be merged, and then I could contribute to this issue #3947 based on the changes in current branch. It's truly a great pleasure:heart:!

[kunaltyagi]

Note to maintainers: We'll need to update the list of required CI for merge

[kunaltyagi]

An error occurred while loading the YAML build pipeline. Unexpected symbol: ')'. Located at position 49 within expression: ne(variables['Build.Reason'], 'ResourceTrigger')). For more help, refer to https://go.microsoft.com/fwlink/?linkid=842996

[ueqri]

I'm really sorry to bring this mistake in the last stage:cry:, and thanks for your hotfix. I promise I will check more carefully at any time especially in online code edits. I apologize for causing this trouble.

[kunaltyagi]

Meh. Happens :)