1. Comment package.yml steps

2. Fix syntax errors

Author: sgilmore10

.github/workflows/package.yml

@@ -35,41 +35,52 @@ jobs:
       - name: Update tags
         run: |
           git fetch --tags --force origin
+      - name: Store release tag name as environment variable
+        run: |
+          echo "RELEASE_TAG_NAME=${{github.ref_name}}" >> "$GITHUB_ENV"
+      - name: Prepare Version
+        # Extract the version string, version with the release-candidate
+        # number string, and release-candidate number from the git tag name
+        # (i.e. RELEASE_TAG_NAME). Store extracted values as environment
+        # variables in GITHUB_ENV for use in subsequent steps. 
+        run: |
+          version_with_rc=${RELEASE_TAG_NAME#apache-arrow-}
+          version=${version_with_rc%-rc*}
+          rc=${version_with_rc#${version}-rc}
+          echo "ARROW_VERSION_WITH_RC=$version_with_rc" >> "$GITHUB_ENV"
+          echo "ARROW_VERSION=$version" >> $GITHUB_ENV
+          echo "ARROW_RC=$rc" >> $GITHUB_ENV
       - name: Extract crossbow job id
+        # Extract the crossbow job ID from the subject associated with the git
+        # tag message. Store the extracted ID as an environment variable in 
+        # GITHUB_ENV for use in subsequent steps. 
         run: |
-          crossbow_job_id=$(git for-each-ref refs/tags/$GIT_TAG_NAME --format='%(contents:subject)')
-          echo "CROSSBOW_JOB_ID=$crossbow_job_id" >> $GITHUB_ENV
-        env:
-          GIT_TAG_NAME: ${{github.ref_name}}
+          crossbow_job_id=$(git for-each-ref refs/tags/$RELEASE_TAG_NAME --format='%(contents:subject)')
+          echo "CROSSBOW_JOB_ID=$crossbow_job_id" >> "$GITHUB_ENV"
       - name: Setup Archery
         run: |
           python3 -m pip install -e dev/archery[crossbow]
       - name: Download artifacts
+        # Download the MLTBX file associated with the crossbow job ID.
+        # Store the path to the downloaded file as an environment variable
+        # in GITHUB_ENV for use in subsequent steps. 
         run: |
           archery crossbow download-artifacts -f matlab -t release-artifacts $CROSSBOW_JOB_ID
+          basefilename=$(find release-artifacts/$CROSSBOW_JOB_ID -name '*.mltbx' -type f | xargs basename)
+          mltbx_file=release-artifacts/$CROSSBOW_JOB_ID/$basefilename
+          echo "ARROW_MLTBX_FILE=$mltbx_file" >> $GITHUB_ENV
       - name: Cut Pre-Release
         run: |
-          mltbx_file=$(find release-artifacts/$CROSSBOW_JOB_ID -name '*.mltbx' -type f | xargs basename)
-          mltbx_path=release-artifacts/$CROSSBOW_JOB_ID/$mltbx_file
-          version_with_rc=${GIT_TAG_NAME#apache-arrow-}
-          version=${version_with_rc%-rc*}
-          rc=${version_with_rc#${version}-rc}
-          
-          target_branch=release-${version_with_rc}
-          title="Apache Arrow {version} RC${rc}"
+          target_branch=release-$ARROW_VERSION_WITH_RC
+          title="Apache Arrow $ARROW_VERSION RC$ARROW_RC"
           repository=${{github.repository}}
-          release_notes="Release Candidate: ${version} RC${rc}"
-          
+          release_notes="Release Candidate: $ARROW_VERSION RC$ARROW_RC"
           gh release create \
-            ${GIT_TAG_NAME} \
-            ${mltbx_path} \
+            $RELEASE_TAG_NAME \
+            $ARROW_MLTBX_FILE \
             --prerelease \
-            --target ${target_branch} \
-            --notes "${release_notes}" \
-            --title "${title}" \
-            --repo ${repository}
-
-        env:
-          GIT_TAG_NAME: ${{github.ref_name}}
-
+            --target $target_branch \
+            --notes "$release_notes" \
+            --title "$title" \
+            --repo $repository