getDiffRanges: decode filename special characters

Author: cklin

src/analyze.ts

@@ -18,6 +18,7 @@ import * as configUtils from "./config-utils";
 import { addDiagnostic, makeDiagnostic } from "./diagnostics";
 import { EnvVar } from "./environment";
 import { FeatureEnablement, Feature } from "./feature-flags";
+import { decodeGitFilePath } from "./git-utils";
 import { isScannedLanguage, Language } from "./languages";
 import { Logger, withGroupAsync } from "./logging";
 import { DatabaseCreationTimings, EventReport } from "./status-report";
@@ -382,7 +383,9 @@ function getDiffRanges(
   // Diff-informed queries expect the file path to be absolute.
   const filename = path.join(
     actionsUtil.getRequiredInput("checkout_path"),
-    fileDiff.filename,
+    // GitHub API preserves non-ASCII characters in file paths as-is, so we only
+    // need to decode the special characters.
+    decodeGitFilePath(fileDiff.filename),
   );
 
   let currentLine = 0;