From fbeabf8863b554e5f49deb2442dc2c85c7a13285 Mon Sep 17 00:00:00 2001
From: Miles Yucht <miles@databricks.com>
Date: Thu, 4 Jan 2024 10:24:36 +0100
Subject: [PATCH 1/5] Fix diff-schema workflow

---
 .github/workflows/schema.yml | 31 ++++++++++++++++++++++---------
 scripts/diff-schema.sh       |  9 +++++----
 2 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/.github/workflows/schema.yml b/.github/workflows/schema.yml
index 40cb42e65d..01b5b26134 100644
--- a/.github/workflows/schema.yml
+++ b/.github/workflows/schema.yml
@@ -7,12 +7,12 @@ on:
   workflow_dispatch:
     inputs:
       base:
-        description: 'Base ref'
-        default: 'master'
+        description: "Base ref"
+        default: "master"
         required: true
       head:
-        description: 'Head ref'
-        default: 'master'
+        description: "Head ref"
+        default: "master"
         required: true
 
 jobs:
@@ -21,26 +21,39 @@ jobs:
 
     steps:
       - if: github.event_name == 'pull_request'
-        name: Checkout
+        name: Checkout PR base commit
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.base_ref }}
+      - if: github.event_name == 'pull_request'
+        name: Checkout PR merge commit
         uses: actions/checkout@v4
 
       - if: github.event_name == 'workflow_dispatch'
-        name: Checkout
+        name: Checkout base commit
         uses: actions/checkout@v4
         with:
           ref: ${{ github.event.inputs.base }}
+      - if: github.event_name == 'workflow_dispatch'
+        name: Checkout head commit
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.inputs.head }}
 
-      - name: 'Setup Go'
+      - name: "Setup Go"
         uses: actions/setup-go@v4
         with:
           go-version: 1.21.x
 
-      - name: 'Setup Terraform'
+      - name: "Setup Terraform"
         uses: hashicorp/setup-terraform@v2
         with:
           terraform_wrapper: false
 
-      - name: 'Install jd'
+      - name: "Install jd"
         run: go install github.com/josephburnett/jd@latest
 
       - run: make diff-schema
+        env:
+          BASE_COMMIT: ${{ github.event_name == 'pull_request' && github.base_ref || github.event.inputs.base }}
+          HEAD_COMMIT: ${{ github.event_name == 'pull_request' && github.head_ref || github.event.inputs.head }}
diff --git a/scripts/diff-schema.sh b/scripts/diff-schema.sh
index bf1e8b9ebb..597228722d 100644
--- a/scripts/diff-schema.sh
+++ b/scripts/diff-schema.sh
@@ -2,7 +2,8 @@
 
 source scripts/libschema.sh
 
-BASE_BRANCH="master"
+BASE=${BASE_COMMIT:-"master"}
+HEAD=${HEAD_COMMIT:-"HEAD"}
 
 checkout_branch() {
     local branch=$1
@@ -15,11 +16,11 @@ if [ -n "$(git status --porcelain)" ]; then
     exit 1
 fi
 
-CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
+CURRENT_BRANCH=$(git rev-parse --abbrev-ref $HEAD)
 NEW_SCHEMA=$(generate_schema)
-checkout_branch $BASE_BRANCH
+checkout_branch $BASE
 CURRENT_SCHEMA=$(generate_schema)
-checkout_branch $CURRENT_BRANCH
+checkout_branch $HEAD
 
 set +e
 jd -color "$CURRENT_SCHEMA" "$NEW_SCHEMA"

From f6d113a3e34c36fd058df410130bbbe119435409 Mon Sep 17 00:00:00 2001
From: Miles Yucht <miles@databricks.com>
Date: Thu, 4 Jan 2024 10:25:56 +0100
Subject: [PATCH 2/5] fix

---
 scripts/diff-schema.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/diff-schema.sh b/scripts/diff-schema.sh
index 597228722d..cc03e7f462 100644
--- a/scripts/diff-schema.sh
+++ b/scripts/diff-schema.sh
@@ -3,7 +3,8 @@
 source scripts/libschema.sh
 
 BASE=${BASE_COMMIT:-"master"}
-HEAD=${HEAD_COMMIT:-"HEAD"}
+CURRENT_BRANCH=$(git rev-parse --abbrev-ref $HEAD)
+HEAD=${HEAD_COMMIT:-$CURRENT_BRANCH}
 
 checkout_branch() {
     local branch=$1
@@ -16,7 +17,6 @@ if [ -n "$(git status --porcelain)" ]; then
     exit 1
 fi
 
-CURRENT_BRANCH=$(git rev-parse --abbrev-ref $HEAD)
 NEW_SCHEMA=$(generate_schema)
 checkout_branch $BASE
 CURRENT_SCHEMA=$(generate_schema)

From f1fe06525ed17b0b6ab7a19f28fb7e5bb14e2182 Mon Sep 17 00:00:00 2001
From: Miles Yucht <miles@databricks.com>
Date: Thu, 4 Jan 2024 10:26:49 +0100
Subject: [PATCH 3/5] set xeo pipefail

---
 scripts/diff-schema.sh | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/diff-schema.sh b/scripts/diff-schema.sh
index cc03e7f462..0bd16e5c90 100644
--- a/scripts/diff-schema.sh
+++ b/scripts/diff-schema.sh
@@ -1,9 +1,10 @@
 #!/usr/bin/env bash
+set -eo pipefail
 
 source scripts/libschema.sh
 
 BASE=${BASE_COMMIT:-"master"}
-CURRENT_BRANCH=$(git rev-parse --abbrev-ref $HEAD)
+CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
 HEAD=${HEAD_COMMIT:-$CURRENT_BRANCH}
 
 checkout_branch() {

From 09d4ea2e5e365010bead24b1631bb4c58fca3136 Mon Sep 17 00:00:00 2001
From: Miles Yucht <miles@databricks.com>
Date: Thu, 4 Jan 2024 12:01:15 +0100
Subject: [PATCH 4/5] handle head correctly

---
 scripts/diff-schema.sh | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/scripts/diff-schema.sh b/scripts/diff-schema.sh
index 0bd16e5c90..ef6239ecad 100644
--- a/scripts/diff-schema.sh
+++ b/scripts/diff-schema.sh
@@ -7,10 +7,10 @@ BASE=${BASE_COMMIT:-"master"}
 CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
 HEAD=${HEAD_COMMIT:-$CURRENT_BRANCH}
 
-checkout_branch() {
-    local branch=$1
-    echo "Checking out branch: $branch"
-    git checkout $branch
+checkout() {
+    local ref=$1
+    echo "Checking out ref: $ref"
+    git checkout $ref
 }
 
 if [ -n "$(git status --porcelain)" ]; then
@@ -18,10 +18,11 @@ if [ -n "$(git status --porcelain)" ]; then
     exit 1
 fi
 
+checkout $HEAD
 NEW_SCHEMA=$(generate_schema)
-checkout_branch $BASE
+checkout $BASE
 CURRENT_SCHEMA=$(generate_schema)
-checkout_branch $HEAD
+checkout $CURRENT_BRANCH
 
 set +e
 jd -color "$CURRENT_SCHEMA" "$NEW_SCHEMA"

From 2f02ad51b5b912bde70b99c464f8b96c7f8b4387 Mon Sep 17 00:00:00 2001
From: Miles Yucht <miles@databricks.com>
Date: Thu, 4 Jan 2024 12:02:39 +0100
Subject: [PATCH 5/5] fix

---
 .github/workflows/schema.yml | 3 ++-
 scripts/diff-schema.sh       | 2 --
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/schema.yml b/.github/workflows/schema.yml
index 01b5b26134..d92a8bdcfa 100644
--- a/.github/workflows/schema.yml
+++ b/.github/workflows/schema.yml
@@ -20,6 +20,8 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      # Check out the base commit first and the head commit second. diff-schema
+      # uses the current commit as the head commit.
       - if: github.event_name == 'pull_request'
         name: Checkout PR base commit
         uses: actions/checkout@v4
@@ -56,4 +58,3 @@ jobs:
       - run: make diff-schema
         env:
           BASE_COMMIT: ${{ github.event_name == 'pull_request' && github.base_ref || github.event.inputs.base }}
-          HEAD_COMMIT: ${{ github.event_name == 'pull_request' && github.head_ref || github.event.inputs.head }}
diff --git a/scripts/diff-schema.sh b/scripts/diff-schema.sh
index ef6239ecad..0daf8ad62e 100644
--- a/scripts/diff-schema.sh
+++ b/scripts/diff-schema.sh
@@ -5,7 +5,6 @@ source scripts/libschema.sh
 
 BASE=${BASE_COMMIT:-"master"}
 CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
-HEAD=${HEAD_COMMIT:-$CURRENT_BRANCH}
 
 checkout() {
     local ref=$1
@@ -18,7 +17,6 @@ if [ -n "$(git status --porcelain)" ]; then
     exit 1
 fi
 
-checkout $HEAD
 NEW_SCHEMA=$(generate_schema)
 checkout $BASE
 CURRENT_SCHEMA=$(generate_schema)