Use GraphQL PR head lookup in get-aspire-cli-pr scripts to avoid REST 422 on large PRs

eng/scripts/get-aspire-cli-pr.ps1

@@ -855,7 +855,50 @@ function Get-PRHeadSHA {
 
     Write-Message "Getting HEAD SHA for PR #$PRNumber" -Level Verbose
 
-    $headSha = Invoke-GitHubAPICall -Endpoint "$Script:GHReposBase/pulls/$PRNumber" -JqFilter ".head.sha" -ErrorMessage "Failed to get HEAD SHA for PR #$PRNumber"
+    if ($Script:Repository -notmatch '^([^/]+)/([^/]+)$') {
+        throw "Invalid repository format '$Script:Repository'. Expected 'owner/name'."
+    }
+    $owner = $Matches[1]
+    $name = $Matches[2]
+
+    $graphqlQuery = 'query($owner:String!, $name:String!, $number:Int!) { repository(owner:$owner, name:$name) { pullRequest(number:$number) { headRefOid } } }'
+    $ghCommand = @(
+        "gh", "api", "graphql",
+        "-f", "query=$graphqlQuery",
+        "-f", "owner=$owner",
+        "-f", "name=$name",
+        "-F", "number=$PRNumber",
+        "--jq", ".data.repository.pullRequest.headRefOid"
+    )
+
+    Write-Message "Calling GitHub API: $($ghCommand -join ' ')" -Level Verbose
+
+    $graphQlError = $null
+    try {
+        $headSha = & $ghCommand[0] $ghCommand[1..($ghCommand.Length-1)] 2>$null
+        if ($LASTEXITCODE -ne 0) {
+            $graphQlError = "gh exited with code $LASTEXITCODE"
+        } elseif ([string]::IsNullOrWhiteSpace($headSha) -or $headSha -eq "null") {
+            $graphQlError = "GraphQL returned empty or null result"
+        } else {
+            # Normalize to a single trimmed string in case of unexpected multi-line output
+            $headSha = ($headSha | Select-Object -First 1).Trim()
+        }
+    }
+    catch {
+        $graphQlError = $_.Exception.Message
+    }
+
+    if ($graphQlError) {
+        Write-Message "GraphQL PR head lookup failed, falling back to REST API: $graphQlError" -Level Verbose
+        try {
+            $headSha = Invoke-GitHubAPICall -Endpoint "$Script:GHReposBase/pulls/$PRNumber" -JqFilter ".head.sha" -ErrorMessage "Failed to get HEAD SHA for PR #$PRNumber using REST fallback"
+        }
+        catch {
+            throw "Failed to get HEAD SHA for PR #$PRNumber with GraphQL query: $graphQlError`nREST fallback error: $($_.Exception.Message)"
+        }
+    }
+
     if ([string]::IsNullOrWhiteSpace($headSha) -or $headSha -eq "null") {
         Write-Message "This could mean:" -Level Info
         Write-Message "  - The PR number does not exist" -Level Info

eng/scripts/get-aspire-cli-pr.sh

@@ -611,14 +611,35 @@ get_pr_head_sha() {
 
     say_verbose "Getting HEAD SHA for PR #$pr_number"
 
-    local head_sha
-    if ! head_sha=$(gh_api_call "${GH_REPOS_BASE}/pulls/$pr_number" ".head.sha" "Failed to get HEAD SHA for PR #$pr_number"); then
-        say_info "This could mean:"
-        say_info "  - The PR number does not exist"
-        say_info "  - You don't have access to the repository"
+    local repo_owner repo_name
+    if [[ "$REPO" =~ ^([^/]+)/([^/]+)$ ]]; then
+        repo_owner="${BASH_REMATCH[1]}"
+        repo_name="${BASH_REMATCH[2]}"
+    else
+        say_error "Invalid repository format '$REPO'. Expected 'owner/name'."
         exit 1
     fi
 
+    local graphql_query='query($owner:String!, $name:String!, $number:Int!) { repository(owner:$owner, name:$name) { pullRequest(number:$number) { headRefOid } } }'
+    local gh_cmd=(gh api graphql -f query="$graphql_query" -f owner="$repo_owner" -f name="$repo_name" -F number="$pr_number" --jq ".data.repository.pullRequest.headRefOid")
+
+    say_verbose "Calling GitHub API: ${gh_cmd[*]}"
+
+    local head_sha
+    if head_sha=$("${gh_cmd[@]}" 2>/dev/null) && [[ -n "$head_sha" && "$head_sha" != "null" ]]; then
+        # GraphQL succeeded with a valid SHA
+        :
+    else
+        say_verbose "GraphQL PR head lookup failed or returned empty, falling back to REST API"
+
+        if ! head_sha=$(gh_api_call "${GH_REPOS_BASE}/pulls/$pr_number" ".head.sha" "Failed to get HEAD SHA for PR #$pr_number using REST fallback"); then
+            say_info "This could mean:"
+            say_info "  - The PR number does not exist"
+            say_info "  - You don't have access to the repository"
+            exit 1
+        fi
+    fi
+
     if [[ -z "$head_sha" || "$head_sha" == "null" ]]; then
         say_error "Could not retrieve HEAD SHA for PR #$pr_number"
         exit 1