fix: ArgumentsReader should warn if missing a value

Closes #1429.

src/lib/utils/options/readers/arguments.ts

@@ -16,6 +16,10 @@ export class ArgumentsReader implements OptionsReader {
     }
 
     read(container: Options, logger: Logger): void {
+        logger.verbose(
+            `Arguments reader reading with: ${JSON.stringify(this.args)}`
+        );
+
         // Make container's type more lax, we do the appropriate checks manually.
         const options = container as Options & {
             setValue(name: string, value: unknown): void;
@@ -57,6 +61,12 @@ export class ArgumentsReader implements OptionsReader {
                         index--;
                     }
                 } else {
+                    if (index === this.args.length) {
+                        // Only boolean values have optional values.
+                        logger.warn(
+                            `--${decl.name} expected a value, but none was given as an argument`
+                        );
+                    }
                     trySet(decl.name, this.args[index]);
                 }
                 seen.add(decl.name);

src/test/utils/options/readers/arguments.test.ts

@@ -1,4 +1,4 @@
-import { deepStrictEqual as equal } from "assert";
+import { deepStrictEqual as equal, ok } from "assert";
 
 import { Options, Logger } from "../../../../lib/utils";
 import { ArgumentsReader } from "../../../../lib/utils/options/readers";
@@ -137,4 +137,21 @@ describe("Options - ArgumentsReader", () => {
         options.removeReaderByName(reader.name);
         equal(check, true, "Reader did not report an error.");
     });
+
+    it("Warns if option is expecting a value but no value is provided", () => {
+        let check = false;
+        class TestLogger extends Logger {
+            warn(msg: string) {
+                ok(msg.includes("--out"));
+                check = true;
+            }
+        }
+
+        const reader = new ArgumentsReader(1, ["--out"]);
+        options.reset();
+        options.addReader(reader);
+        options.read(new TestLogger());
+        options.removeReaderByName(reader.name);
+        equal(check, true, "Reader did not report an error.");
+    });
 });