From 6bbc24757053ccd1ff36fc5d40b5acbf29f00e30 Mon Sep 17 00:00:00 2001
From: Timothee Guerin <tiguerin@microsoft.com>
Date: Fri, 14 Jun 2024 08:13:27 -0700
Subject: [PATCH] Fix formatting of object and array literal in decorator
 (#3577)

Currently formats to
```
@example(
  #{
    id: "some",
    bar: "thing",
    date: utcDateTime.fromISO("2020-01-01T00:00:00Z"),
    unixDate: unixTimestamp32.fromISO("2020-01-01T00:00:00Z"),
    encodedAsRfc7231: utcDateTime.fromISO("2020-01-01T00:00:00Z"),
    dob: plainDate.fromISO("2020-01-01"),
    timeout: duration.fromISO("PT1M"),
    timeoutInSeconds: duration.fromISO("PT1M1.5S"),
    timeoutInSecondsFloat: duration.fromISO("PT0.5S"),
  }
)
```

woudl get formatted to

```

@example(#{
    id: "some",
    bar: "thing",
    date: utcDateTime.fromISO("2020-01-01T00:00:00Z"),
    unixDate: unixTimestamp32.fromISO("2020-01-01T00:00:00Z"),
    encodedAsRfc7231: utcDateTime.fromISO("2020-01-01T00:00:00Z"),
    dob: plainDate.fromISO("2020-01-01"),
    timeout: duration.fromISO("PT1M"),
    timeoutInSeconds: duration.fromISO("PT1M1.5S"),
    timeoutInSecondsFloat: duration.fromISO("PT0.5S"),
})
```
---
 ...ject-array-literal-hug-2024-5-13-20-4-7.md |  8 +++
 .../compiler/src/formatter/print/printer.ts   |  4 +-
 .../compiler/test/formatter/formatter.test.ts | 53 +++++++++++++++++++
 3 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 .chronus/changes/fix-formatting-object-array-literal-hug-2024-5-13-20-4-7.md

diff --git a/.chronus/changes/fix-formatting-object-array-literal-hug-2024-5-13-20-4-7.md b/.chronus/changes/fix-formatting-object-array-literal-hug-2024-5-13-20-4-7.md
new file mode 100644
index 0000000000..49283b977e
--- /dev/null
+++ b/.chronus/changes/fix-formatting-object-array-literal-hug-2024-5-13-20-4-7.md
@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/compiler"
+---
+
+Fix formatting of object and array literal in decorator to hug parenthesis
diff --git a/packages/compiler/src/formatter/print/printer.ts b/packages/compiler/src/formatter/print/printer.ts
index 969ec4bb81..c982c709be 100644
--- a/packages/compiler/src/formatter/print/printer.ts
+++ b/packages/compiler/src/formatter/print/printer.ts
@@ -700,12 +700,14 @@ function printCallOrDecoratorArgs(
   }
 
   // So that decorator with single object arguments have ( and { hugging.
-  // @deco({
+  // @deco(#{
   //   value: "foo"
   // })
   const shouldHug =
     node.arguments.length === 1 &&
     (node.arguments[0].kind === SyntaxKind.ModelExpression ||
+      node.arguments[0].kind === SyntaxKind.ObjectLiteral ||
+      node.arguments[0].kind === SyntaxKind.ArrayLiteral ||
       node.arguments[0].kind === SyntaxKind.StringLiteral ||
       node.arguments[0].kind === SyntaxKind.StringTemplateExpression);
 
diff --git a/packages/compiler/test/formatter/formatter.test.ts b/packages/compiler/test/formatter/formatter.test.ts
index 2443435437..39b04d7ed8 100644
--- a/packages/compiler/test/formatter/formatter.test.ts
+++ b/packages/compiler/test/formatter/formatter.test.ts
@@ -852,6 +852,59 @@ scalar Foo {
       });
     });
   });
+
+  describe("scalar constructor call", () => {
+    it("simple call", async () => {
+      await assertFormat({
+        code: `
+const foo     = utcDateTime.   fromISO(
+  "abc"  );
+`,
+        expected: `
+const foo = utcDateTime.fromISO("abc");
+`,
+      });
+    });
+
+    it("hug object literal", async () => {
+      await assertFormat({
+        code: `
+const foo     = utcDateTime.   fromFoo(#{ name: "abc",
+        multiline1: "abc",
+  multiline2: "abc",
+    multiline3: "abc",  });
+`,
+        expected: `
+const foo = utcDateTime.fromFoo(#{
+  name: "abc",
+  multiline1: "abc",
+  multiline2: "abc",
+  multiline3: "abc",
+});
+`,
+      });
+    });
+
+    it("hug array literal", async () => {
+      await assertFormat({
+        code: `
+const foo     = utcDateTime.   fromFoo(#[
+        "very very long array",
+    "very very long array",
+  "very very long array"
+]);
+`,
+        expected: `
+const foo = utcDateTime.fromFoo(#[
+  "very very long array",
+  "very very long array",
+  "very very long array"
+]);
+`,
+      });
+    });
+  });
+
   describe("comments", () => {
     it("format comment at position 0", async () => {
       await assertFormat({