feat: add elseif handler syntax support in template expression rendering (#elseif, #else-if, #else_if variants)

actions/setup/js/fuzz_template_branch_harness.cjs

@@ -0,0 +1,61 @@
+// @ts-check
+/**
+ * Fuzz harness for {{#if / #elseif / #else}} template branch selection and rendering.
+ *
+ * Reads a JSON test case from stdin:
+ *   { ifCondition: string, body: string }   — for selectBranch
+ *   { markdown: string }                     — for renderMarkdownTemplate
+ *
+ * Writes the result as JSON to stdout:
+ *   { result: string|null, error: string|null }
+ *
+ * Used by the Go fuzz driver in template_conditional_js_fuzz_test.go.
+ */
+
+const { selectBranch } = require("./template_branch.cjs");
+const { isTruthy } = require("./is_truthy.cjs");
+
+// Minimal shim so renderMarkdownTemplate can call core.info
+if (!global.core) {
+  global.core = {
+    info: () => {},
+    warning: () => {},
+    setFailed: () => {},
+  };
+}
+
+const renderTemplateScript = require("fs").readFileSync(require("path").join(__dirname, "render_template.cjs"), "utf8");
+const renderMarkdownTemplateMatch = renderTemplateScript.match(/function renderMarkdownTemplate\(markdown\)\s*{[\s\S]*?return result;[\s\S]*?}/);
+if (!renderMarkdownTemplateMatch) throw new Error("Could not extract renderMarkdownTemplate");
+const renderMarkdownTemplate = eval(`(${renderMarkdownTemplateMatch[0]})`);
+
+if (require.main === module) {
+  let input = "";
+  process.stdin.on("data", chunk => {
+    input += chunk;
+  });
+  process.stdin.on("end", () => {
+    try {
+      const parsed = JSON.parse(input);
+
+      let result;
+      if (Object.prototype.hasOwnProperty.call(parsed, "ifCondition")) {
+        // selectBranch test
+        result = { result: selectBranch(parsed.ifCondition, parsed.body || ""), error: null };
+      } else if (Object.prototype.hasOwnProperty.call(parsed, "markdown")) {
+        // renderMarkdownTemplate test
+        result = { result: renderMarkdownTemplate(parsed.markdown || ""), error: null };
+      } else {
+        result = { result: null, error: "Unknown test type: expected 'ifCondition' or 'markdown' key" };
+      }
+
+      process.stdout.write(JSON.stringify(result));
+      process.exit(0);
+    } catch (err) {
+      process.stdout.write(JSON.stringify({ result: null, error: err instanceof Error ? err.message : String(err) }));
+      process.exit(1);
+    }
+  });
+}
+
+module.exports = { selectBranch, renderMarkdownTemplate };