From 5f75aa34e6bd946623d2212cdb68a78238be3db8 Mon Sep 17 00:00:00 2001
From: Carlos Scheidegger <carlos.scheidegger@rstudio.com>
Date: Tue, 3 Dec 2024 09:51:34 -0700
Subject: [PATCH] allow 'info' to not error in quarto check

---
 src/command/check/check.ts        | 24 +++++++++++++++---------
 src/command/check/cmd.ts          | 18 ++++--------------
 src/typing/dynamic.ts             | 27 +++++++++++++++++++++++++++
 tests/unit/typing/dynamic.test.ts | 19 +++++++++++++++++++
 4 files changed, 65 insertions(+), 23 deletions(-)
 create mode 100644 src/typing/dynamic.ts
 create mode 100644 tests/unit/typing/dynamic.test.ts

diff --git a/src/command/check/check.ts b/src/command/check/check.ts
index 65571392bf..9cc4085b83 100644
--- a/src/command/check/check.ts
+++ b/src/command/check/check.ts
@@ -47,16 +47,20 @@ import { notebookContext } from "../../render/notebook/notebook-context.ts";
 import { typstBinaryPath } from "../../core/typst.ts";
 import { quartoCacheDir } from "../../core/appdirs.ts";
 import { isWindows } from "../../deno_ral/platform.ts";
+import { checkStringEnum } from "../../typing/dynamic.ts";
 
-const kIndent = "      ";
+export const kTargets = [
+  "install",
+  "info",
+  "jupyter",
+  "knitr",
+  "versions",
+  "all",
+] as const;
+export type Target = typeof kTargets[number];
+export const checkTargetType = checkStringEnum(...kTargets);
 
-export type Target =
-  | "install"
-  | "jupyter"
-  | "knitr"
-  | "versions"
-  | "info"
-  | "all";
+const kIndent = "      ";
 
 export async function check(target: Target): Promise<void> {
   const services = renderServices(notebookContext());
@@ -82,7 +86,9 @@ export async function check(target: Target): Promise<void> {
   }
 }
 
-// Currently this doesn't check anything, but
+// Currently this doesn't check anything
+// but it's a placeholder for future checks
+// and the message is useful for troubleshooting
 async function checkInfo(_services: RenderServices) {
   const cacheDir = quartoCacheDir();
   completeMessage("Checking environment information...");
diff --git a/src/command/check/cmd.ts b/src/command/check/cmd.ts
index 0c8fdb06ae..66061bbffb 100644
--- a/src/command/check/cmd.ts
+++ b/src/command/check/cmd.ts
@@ -4,12 +4,8 @@
  * Copyright (C) 2021-2022 Posit Software, PBC
  */
 
-import { error } from "../../deno_ral/log.ts";
-
 import { Command } from "cliffy/command/mod.ts";
-import { check, Target } from "./check.ts";
-
-const kTargets = ["install", "jupyter", "knitr", "versions", "all"];
+import { check, checkTargetType } from "./check.ts";
 
 export const checkCommand = new Command()
   .name("check")
@@ -22,13 +18,7 @@ export const checkCommand = new Command()
   .example("Check Jupyter engine", "quarto check jupyter")
   .example("Check Knitr engine", "quarto check knitr")
   .example("Check installation and all engines", "quarto check all")
-  .action(async (_options: unknown, target?: string) => {
-    target = target || "all";
-    if (!kTargets.includes(target)) {
-      error(
-        "Invalid target '" + target + "' (valid targets are " +
-          kTargets.join(", ") + ").",
-      );
-    }
-    await check(target as Target);
+  .action(async (_options: unknown, targetStr?: string) => {
+    targetStr = targetStr || "all";
+    await check(checkTargetType(targetStr));
   });
diff --git a/src/typing/dynamic.ts b/src/typing/dynamic.ts
new file mode 100644
index 0000000000..7d7ee22411
--- /dev/null
+++ b/src/typing/dynamic.ts
@@ -0,0 +1,27 @@
+/*
+ * dynamic.ts
+ *
+ * Tools for managing the interface between dynamic and static typing
+ * in Quarto.
+ *
+ * Ideally, every usage of `any` or `as` would appear in this file.
+ *
+ * Copyright (C) 2024 Posit Software, PBC
+ */
+
+import { DynamicTypeCheckError } from "../core/lib/error.ts";
+
+export const checkStringEnum = <T extends string>(
+  ...values: T[]
+): (value: string) => T => {
+  const valueSet: Set<string> = new Set(values);
+  return (value: string): T => {
+    if (!valueSet.has(value)) {
+      throw new DynamicTypeCheckError(
+        "Invalid value '" + value + "' (valid values are " +
+          values.join(", ") + ").",
+      );
+    }
+    return value as unknown as T;
+  };
+};
diff --git a/tests/unit/typing/dynamic.test.ts b/tests/unit/typing/dynamic.test.ts
new file mode 100644
index 0000000000..1b8422dcba
--- /dev/null
+++ b/tests/unit/typing/dynamic.test.ts
@@ -0,0 +1,19 @@
+/*
+* dynamic.test.ts
+*
+* Copyright (C) 2024 Posit Software, PBC
+*
+*/
+
+import { checkStringEnum } from "../../../src/typing/dynamic.ts";
+import { unitTest } from "../../test.ts";
+import { assert, assertThrows } from "testing/asserts";
+
+// deno-lint-ignore require-await
+unitTest("checkStringEnum", async () => {
+  const check = checkStringEnum("a", "b", "c");
+  assert(check("a") === "a");
+  assert(check("b") === "b");
+  assert(check("c") === "c");
+  assertThrows(() => check("d"), Error, "Invalid value 'd' (valid values are a, b, c).");
+});
\ No newline at end of file