TEP-0090: Matrix - Status

[TEP-0090: Matrix][tep-0090] proposed executing a `PipelineTask` in
parallel `TaskRuns` and `Runs` with substitutions from combinations
of `Parameters` in a `Matrix`.

In this change, we describe how the status of a `PipelineRun` with
a matrixed `PipelineTask` would be in full and minimal modes.

Previously, we had included `matrixId` to the `PipelineRun` status
so that it can help with identifying `Results` from fanned out
`TaskRuns` or `Runs`. However, we ended up descoping that problem
so that it can be addressed when TEP-0075 and TEP-0076 are implemented.
See [`Results` from fanned-out `PipelineTasks`][results] for details.
In this change, we remove the `matrixId` in `PipelineRun` status so
that the problem can be addressed completely later.

[tep-0090]: https://github.com/tektoncd/community/blob/main/teps/0090-matrix.md
[results]: https://github.com/tektoncd/community/blob/main/teps/0090-matrix.md#results-from-fanned-out-pipelinetasks

teps/0090-matrix.md

@@ -2,7 +2,7 @@
 status: implementable
 title: Matrix
 creation-date: '2021-10-13'
-last-updated: '2022-02-14'
+last-updated: '2022-06-06'
 authors:
 - '@jerop'
 - '@pritidesai'
@@ -46,7 +46,6 @@ see-also:
   - [Parameters](#parameters)
     - [Substituting String Parameters in the Tasks](#substituting-string-parameters-in-the-tasks)
     - [Substituting Array Parameters in the Tasks](#substituting-array-parameters-in-the-tasks)
-    - [Combinations of Parameters in the Matrix](#combinations-of-parameters-in-the-matrix)
   - [Results](#results)
     - [Specifying Results in the Matrix](#specifying-results-in-the-matrix)
     - [Results from Fanned Out PipelineTasks](#results-from-fanned-out-pipelinetasks)
@@ -61,6 +60,7 @@ see-also:
   - [When Expressions](#when-expressions)
   - [Retries](#retries)
   - [Timeouts](#timeouts)
+  - [Status](#status)
 - [Design Evaluation](#design-evaluation)
   - [API Conventions](#api-conventions)
   - [Reusability](#reusability)
@@ -1021,34 +1021,6 @@ We plan to provide minimum feature set needed to meet the use cases, as describe
 [simplicity][simplicity] design principle. However, this remains an option we can explore
 later if we have use cases for it and already support `Arrays of Arrays` in Tekton Pipelines.
 
-#### Combinations of Parameters in the Matrix
-
-We need a way to identify a specific combination of `Parameters` in the `Matrix` so that
-we can map it to a given `TaskRun` and its components, such as `Results`. We cannot rely
-on the ordering of the `Parameters` in the `Matrix` to be maintained as specified in the
-`Pipeline`. We propose that we add the generated combinations identifications to the
-`PipelineRunStatusFields` in `PipelineRunStatus`. For example:
-
-```yaml
-  taskRuns:
-    matrixed-pr-foo-0:
-      pipelineTaskName: foo
-      matrixId: 0
-      status:
-        ...
-    matrixed-pr-foo-1:
-      pipelineTaskName: foo
-      matrixId: 1
-      status:
-        ...
-```
-
-The `Parameters` were used for a given `TaskRun` or `Runs` would available in the `TaskRun`
-status itself. The `matrixId` in the `PipelineRunStatus` is useful in identifying that the
-`TaskRun` is part of a `Matrix`, especially if the `TaskRun` name was too long so got hashed.
-This is also in line with providing the minimal information needed in the `PipelineRunStatus`
-as discussed in [TEP-0100: Embedded TaskRuns and Runs Status in PipelineRuns][tep-0100].
-
 ### Results
 
 #### Specifying Results in the Matrix
@@ -1340,6 +1312,48 @@ spec:
         name: build-push
 ```
 
+### Status
+
+The status of `PipelineRuns` with fanned-out `PipelineTasks` will list all the `TaskRuns` and `Runs` created.
+
+In [TEP-0100][tep-0100] we proposed changes to `PipelineRun` status to reduce the amount of information stored about
+the status of `TaskRuns` and `Runs` to improve performance, reduce memory bloat and improve extensibility. Now that
+those changes have been implemented, the `PipelineRun` status is set up to handle `Matrix` without exacerbating the
+performance and storage issues that were there before.
+
+We will populate `ChildReferences` for all fanned out `TaskRuns` and `Runs`, as shown below:
+
+```yaml
+apiVersion: tekton.dev/v1beta1
+kind: PipelineRun
+metadata:
+  name: matrixed-pr
+  ...
+spec:
+  ...
+status:
+  completionTime: "2020-05-04T02:19:14Z"
+  conditions:
+    - lastTransitionTime: "2020-05-04T02:19:14Z"
+      message: "Tasks Completed: 4, Skipped: 0"
+      reason: Succeeded
+      status: "True"
+      type: Succeeded
+  startTime: "2020-05-04T02:00:11Z"
+  childReferences:
+    - apiVersion: tekton.dev/v1beta1
+      kind: TaskRun
+      name: matrixed-pr-foo-0
+      pipelineTaskName: foo
+    - apiVersion: tekton.dev/v1beta1
+      kind: TaskRun
+      name: matrixed-pr-foo-1
+      pipelineTaskName: foo
+```
+
+The `ChildReferences` will be populated for matrixed `PipelineTasks` regardless of the embedded status flags
+because that is the API behavior we're migrating to.
+
 ## Design Evaluation
 
 ### API Conventions

teps/README.md

@@ -234,7 +234,7 @@ This is the complete list of Tekton teps:
 |[TEP-0086](0086-changing-the-way-result-parameters-are-stored.md) | Changing the way result parameters are stored | proposed | 2022-04-07 |
 |[TEP-0088](0088-result-summaries.md) | Tekton Results - Record Summaries | proposed | 2021-10-01 |
 |[TEP-0089](0089-nonfalsifiable-provenance-support.md) | Non-falsifiable provenance support | implementable | 2022-01-18 |
-|[TEP-0090](0090-matrix.md) | Matrix | implementable | 2022-02-14 |
+|[TEP-0090](0090-matrix.md) | Matrix | implementable | 2022-06-06 |
 |[TEP-0092](0092-scheduling-timeout.md) | Scheduling Timeout | implementable | 2022-04-11 |
 |[TEP-0094](0094-configuring-resources-at-runtime.md) | Configuring Resources at Runtime | implemented | 2022-03-11 |
 |[TEP-0095](0095-common-repository-configuration.md) | Common Repository Configuration | proposed | 2021-11-29 |