Diff-informed analysis: disable for GHES below 3.19

Author: cklin

src/diff-informed-analysis-utils.ts

@@ -1,11 +1,15 @@
 import * as fs from "fs";
 import * as path from "path";
 
+import * as semver from "semver";
+
 import * as actionsUtil from "./actions-util";
 import type { PullRequestBranches } from "./actions-util";
+import { getGitHubVersion } from "./api-client";
 import type { CodeQL } from "./codeql";
 import { Feature, FeatureEnablement } from "./feature-flags";
 import { Logger } from "./logging";
+import { GitHubVariant, parseGhesVersion } from "./util";
 
 /**
  * Check if the action should perform diff-informed analysis.
@@ -37,6 +41,14 @@ export async function getDiffInformedAnalysisBranches(
     return undefined;
   }
 
+  const gitHubVersion = await getGitHubVersion();
+  if (
+    gitHubVersion.type === GitHubVariant.GHES &&
+    semver.lt(parseGhesVersion(gitHubVersion.version), "3.19.0")
+  ) {
+    return undefined;
+  }
+
   const branches = actionsUtil.getPullRequestBranches();
   if (!branches) {
     logger.info(