Created separate workflow for running mypy_primer on push to main.

.github/workflows/mypy_primer_comment.yaml

@@ -3,7 +3,7 @@ name: Comment with mypy_primer diff
 on:
   workflow_run:
     workflows:
-      - Run mypy_primer
+      - Run mypy_primer on PR
     types:
       - completed
 

.github/workflows/mypy_primer_pr.yaml

@@ -1,4 +1,4 @@
-name: Run mypy_primer
+name: Run mypy_primer on PR
 
 on:
   pull_request:
@@ -13,13 +13,13 @@ concurrency:
 
 jobs:
   mypy_primer:
-    name: Run mypy_primer
+    name: Run mypy_primer on PR
     runs-on: ubuntu-latest
     permissions:
       contents: read
     strategy:
       matrix:
-        shard-index: [0, 1, 2]
+        shard-index: [0]
       fail-fast: false
     steps:
       - uses: actions/checkout@v3
@@ -38,6 +38,12 @@ jobs:
         run: |
           cd pyright_to_test
           echo "new commit"
+          git rev-list --format=%s --max-count=1 $GITHUB_SHA
+
+          MERGE_BASE=$(git merge-base $GITHUB_SHA origin/$GITHUB_BASE_REF)
+          git checkout -b base_commit $MERGE_BASE
+          echo "base commit"
+          git rev-list --format=%s --max-count=1 base_commit
 
           echo ''
           cd ..
@@ -46,8 +52,8 @@ jobs:
             mypy_primer \
             --repo pyright_to_test \
             --type-checker pyright \
-            --new $GITHUB_SHA \
-            --num-shards 3 --shard-index ${{ matrix.shard-index }} \
+            --new $GITHUB_SHA --old base_commit \
+            --num-shards 1 --shard-index ${{ matrix.shard-index }} \
             --debug \
             --output concise \
             | tee diff_${{ matrix.shard-index }}.txt

.github/workflows/mypy_primer_push.yaml

@@ -0,0 +1,59 @@
+name: Run mypy_primer on push
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'packages/pyright/**'
+      - 'packages/pyright-internal/src/**'
+      - 'packages/pyright-internal/typeshed-fallback/**'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  mypy_primer:
+    name: Run mypy_primer on push
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    strategy:
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          path: pyright_to_test
+          fetch-depth: 0
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.10'
+      - name: Install dependencies
+        run: |
+          python -m pip install -U pip
+          pip install git+https://github.com/hauntsaninja/mypy_primer.git
+      - name: Run mypy_primer
+        shell: bash
+        run: |
+          cd pyright_to_test
+          echo "new commit"
+          git rev-list --format=%s --max-count=1 $GITHUB_SHA
+
+          cd ..
+          # fail action if exit code isn't zero or one
+          (
+            mypy_primer \
+            --repo pyright_to_test \
+            --type-checker pyright \
+            --new $GITHUB_SHA \
+            --debug \
+            --output concise \
+            | tee diff.txt
+          ) || [ $? -eq 1 ]
+      - name: Upload mypy_primer diff
+        uses: actions/upload-artifact@v3
+        with:
+          name: mypy_primer_diffs
+          path: diff.txt