diff --git a/lib/entry-points.js b/lib/entry-points.js
index 230d5b40f..9316d2502 100644
--- a/lib/entry-points.js
+++ b/lib/entry-points.js
@@ -173028,6 +173028,19 @@ function addNoLanguageDiagnostic(config, diagnostic) {
     unwrittenDefaultLanguageDiagnostics.push(diagnostic);
   }
 }
+function writeDiagnosticFile(diagnosticsPath, diagnostic) {
+  (0, import_fs.mkdirSync)(diagnosticsPath, { recursive: true });
+  const uniqueSuffix = (diagnosticCounter++).toString();
+  const sanitizedTimestamp = diagnostic.timestamp.replace(
+    /[^a-zA-Z0-9.-]/g,
+    ""
+  );
+  const jsonPath = import_path2.default.resolve(
+    diagnosticsPath,
+    `codeql-action-${sanitizedTimestamp}-${uniqueSuffix}.json`
+  );
+  (0, import_fs.writeFileSync)(jsonPath, JSON.stringify(diagnostic));
+}
 function writeDiagnostic(config, language, diagnostic) {
   const logger2 = getActionsLogger();
   const databasePath = language ? getCodeQLDatabasePath(config, language) : config.dbLocation;
@@ -173037,17 +173050,7 @@ function writeDiagnostic(config, language, diagnostic) {
     "codeql-action"
   );
   try {
-    (0, import_fs.mkdirSync)(diagnosticsPath, { recursive: true });
-    const uniqueSuffix = (diagnosticCounter++).toString();
-    const sanitizedTimestamp = diagnostic.timestamp.replace(
-      /[^a-zA-Z0-9.-]/g,
-      ""
-    );
-    const jsonPath = import_path2.default.resolve(
-      diagnosticsPath,
-      `codeql-action-${sanitizedTimestamp}-${uniqueSuffix}.json`
-    );
-    (0, import_fs.writeFileSync)(jsonPath, JSON.stringify(diagnostic));
+    writeDiagnosticFile(diagnosticsPath, diagnostic);
   } catch (err) {
     logger2.warning(`Unable to write diagnostic message to database: ${err}`);
     logger2.debug(JSON.stringify(diagnostic));
diff --git a/src/diagnostics.ts b/src/diagnostics.ts
index fa0e87c04..caab84934 100644
--- a/src/diagnostics.ts
+++ b/src/diagnostics.ts
@@ -177,6 +177,33 @@ export function addNoLanguageDiagnostic(
   }
 }
 
+/**
+ * Writes {@link diagnostic} to a file in {@link diagnosticsPath}.
+ */
+function writeDiagnosticFile(
+  diagnosticsPath: string,
+  diagnostic: DiagnosticMessage,
+) {
+  // Create the directory if it doesn't exist yet.
+  mkdirSync(diagnosticsPath, { recursive: true });
+
+  // Include a monotonically increasing suffix to avoid filename collisions
+  // between diagnostics produced within the same millisecond.
+  const uniqueSuffix = (diagnosticCounter++).toString();
+  // We should only need to remove colons, but to be defensive, only allow a restricted set of
+  // characters.
+  const sanitizedTimestamp = diagnostic.timestamp.replace(
+    /[^a-zA-Z0-9.-]/g,
+    "",
+  );
+  const jsonPath = path.resolve(
+    diagnosticsPath,
+    `codeql-action-${sanitizedTimestamp}-${uniqueSuffix}.json`,
+  );
+
+  writeFileSync(jsonPath, JSON.stringify(diagnostic));
+}
+
 /**
  * Writes the given diagnostic to the database.
  *
@@ -200,24 +227,7 @@ function writeDiagnostic(
   );
 
   try {
-    // Create the directory if it doesn't exist yet.
-    mkdirSync(diagnosticsPath, { recursive: true });
-
-    // Include a monotonically increasing suffix to avoid filename collisions
-    // between diagnostics produced within the same millisecond.
-    const uniqueSuffix = (diagnosticCounter++).toString();
-    // We should only need to remove colons, but to be defensive, only allow a restricted set of
-    // characters.
-    const sanitizedTimestamp = diagnostic.timestamp.replace(
-      /[^a-zA-Z0-9.-]/g,
-      "",
-    );
-    const jsonPath = path.resolve(
-      diagnosticsPath,
-      `codeql-action-${sanitizedTimestamp}-${uniqueSuffix}.json`,
-    );
-
-    writeFileSync(jsonPath, JSON.stringify(diagnostic));
+    writeDiagnosticFile(diagnosticsPath, diagnostic);
   } catch (err) {
     logger.warning(`Unable to write diagnostic message to database: ${err}`);
     logger.debug(JSON.stringify(diagnostic));