[Index Management] Fix @custom component template creation

[kapral18]

Addresses #237916.

• Fix /component_templates/{name}/datastreams route to return empty when the component template is not referenced by any index template, preventing unintended apply-mappings and the rollover modal for brand-new @custom component templates
• add test coverage for component_templates routes folder
• refactor testing setup

Manual test setup

1. Run latest es/kibana locally from kibana repo source
2. In DevTools:

PUT _index_template/foo-template
{
  "index_patterns": ["foo-ds-*"],
  "data_stream": {},
  "template": {
    "mappings": {
      "properties": {
        "message": { "type": "text" },
        "timestamp": { "type": "date" }
      }
    }
  }
}

PUT _data_stream/foo-ds-1

# Introduce a conflict mapping in index-template
PUT _index_template/foo-template
{
  "index_patterns": ["foo-ds-*"],
  "data_stream": {},
  "template": {
    "mappings": {
      "properties": {
        "message": { "type": "boolean" },
        "timestamp": { "type": "date" }
      }
    }
  }
}

4. Go to /app/management/data/index_management/component_templates
5. Create a new template that is not referenced by any index_template and has a @custom suffix, ex. random-1234@custom
6. Verify the behavior: Before this PR change a modal asking to rollover conflicting data-stream foo-ds-1 will appear, and after this PR no modal will appear.

!Important Do not click apply now and rollover in the modal as it will mess up setup to verify before/after fix.

Release note

• Fixed a bug in component template creation flow where a new component template with @custom suffix in name would lead to updating mappings of all unrelated data-streams and a popup would appear asking to rollover conflicting ones.

[elasticmachine]

Pinging @elastic/kibana-management (Team:Kibana Management)

[ElenaStoeva]

Hi @kapral18, I tested locally and I don't see the modal. However, I also don't see it without the changes from this PR so I might be doing something wrong - let's meet tomorrow and discuss this.

[ElenaStoeva]

As per our offline discussion, we found that the issue with the modal is not reproducible in main, and we also couldn't verify the modal is still working correctly in main, so we need to get some more context on this functionality before merging the fix.

[kapral18]

@ElenaStoeva the problem in the end wasn't the issue itself not reproducing on main but rather me not providing a good repro instruction. I found a better more stably repro instruction that works everywhere. I updated the description of the PR with the instruction. It's also simpler. Let me know. Thanks and apologies for confusion

[ElenaStoeva]

Thanks for updating the instructions! Tested locally and verified that:

• The modal is not displayed when the component template is not referenced by a conflicting index template
• The modal is not displayed when the component is referenced by a non-conflicting index template
• The modal is correctly displayed when the component template is referenced by a conflicting index template

Code changes also lgtm. Thanks for adding tests!

I'm approving to unblock the PR, but I wonder if we should test this behavior somehow in a follow-up, maybe with functional tests. Wdyt?

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: ccf807b

Failed CI Steps

• FTR Configs #140

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
indexManagement	691.8KB	691.8KB	+27.0B

History

• 💔 Build #349660 failed 9f52716
• 💔 Build #349520 failed 9282f3c
• 💛 Build #348746 was flaky 60d1015
• 💔 Build #348521 failed c869ae4

[kibanamachine]

Starting backport for target branches: 8.18, 8.19, 9.1, 9.2

https://github.com/elastic/kibana/actions/runs/18413797934

[kibanamachine]

💔 Some backports could not be created

Status	Branch	Result
✅	8.18
❌	8.19	Backport failed because of merge conflicts You might need to backport the following PRs to 8.19: - [Search][Accessibility] Show error text when fields are invalid (#238284) - [Security Solution] Add FTR tests for prebuilt rules OOM testing (#236891)
❌	9.1	Backport failed because of merge conflicts You might need to backport the following PRs to 9.1: - [Search][Accessibility] Show error text when fields are invalid (#238284) - [Security Solution] Add FTR tests for prebuilt rules OOM testing (#236891)
✅	9.2

Note: Successful backport PRs will be merged automatically after passing CI.

Manual backport

To create the backport manually run:

node scripts/backport --pr 237952

Questions ?

Please refer to the Backport tool documentation

[kapral18]

💚 All backports created successfully

Status	Branch	Result
✅	9.1
✅	8.19

Note: Successful backport PRs will be merged automatically after passing CI.

Questions ?

Please refer to the Backport tool documentation