HACK: allow channel to be specified to set-channel action

.github/actions/set-channel/action.yml

@@ -2,12 +2,23 @@ name: Set Channel for Build Matrix Generation/Binary Build Step
 
 description: Add CHANNEL to GITHUB_ENV
 
+inputs:
+  channel:
+    description: 'Channel to use (nightly or test). If not provided, will be auto-detected based on git ref'
+    required: false
+    default: ''
 
 runs:
   using: composite
   steps:
+    - name: Set CHANNEL from input
+      if: ${{ inputs.channel != '' }}
+      shell: bash
+      run: |
+        set -euxo pipefail
+        echo "CHANNEL=${{ inputs.channel }}" >> "${GITHUB_ENV}"
     - name: Set CHANNEL for tagged pushes
-      if: ${{ github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/') }}
+      if: ${{ inputs.channel == '' && github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/') }}
       shell: bash
       run: |
         set -euxo pipefail
@@ -16,7 +27,7 @@ runs:
           echo "CHANNEL=test" >> "${GITHUB_ENV}"
         fi
     - name: Set Release CHANNEL for release
-      if: ${{ (github.event_name == 'pull_request' && startsWith(github.base_ref, 'release')) || startsWith(github.ref, 'refs/heads/release') }}
+      if: ${{ inputs.channel == '' && ((github.event_name == 'pull_request' && startsWith(github.base_ref, 'release')) || startsWith(github.ref, 'refs/heads/release')) }}
       shell: bash
       run: |
         set -euxo pipefail

.github/workflows/build_wheels_linux.yml

@@ -122,6 +122,10 @@ on:
         description: 'Timeout for the job (in minutes)'
         default: 120
         type: number
+      channel:
+        description: 'Channel to use for pytorch package. Defaults to nightly, can be set to test for release candidates'
+        default: 'nightly'
+        type: string
     secrets:
       PYPI_API_TOKEN:
         description: An optional token to upload to pypi
@@ -195,6 +199,8 @@ jobs:
           conda config --set ssl_verify False
           echo "/opt/conda/bin" >> $GITHUB_PATH
       - uses: ./test-infra/.github/actions/set-channel
+        with:
+          channel: ${{ inputs.channel }}
       - name: Set PYTORCH_VERSION
         if: ${{ env.CHANNEL == 'test' }}
         run: |