fix: escape deprecation strings in SDL (#791)

Fixes #790

CHANGELOG.md

@@ -26,6 +26,7 @@ This project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html
   certain circumstances.
 - The generator now uses the same re-casing as codegen - leading to less bugs.
 - The generator will now rename more QueryFragment fields that require it.
+- `cynic-introspection` now escapes deprecated strings that require it in SDL.
 
 ## v3.2.2 - 2023-06-26
 

cynic-introspection/src/schema/sdl.rs

@@ -328,7 +328,9 @@ impl Display for DeprecatedDisplay<'_> {
         match self.0 {
             Deprecated::No => {}
             Deprecated::Yes(None) => write!(f, " @deprecated")?,
-            Deprecated::Yes(Some(reason)) => write!(f, " @deprecated(reason: \"{reason}\")")?,
+            Deprecated::Yes(Some(reason)) => {
+                write!(f, " @deprecated(reason: \"{}\")", escape_string(reason))?
+            }
         }
         Ok(())
     }
@@ -349,3 +351,18 @@ impl Display for SpecifiedByDisplay<'_> {
 pub fn indented<D>(f: &mut D) -> indenter::Indented<'_, D> {
     indenter::indented(f).with_str("  ")
 }
+
+fn escape_string(src: &str) -> String {
+    let mut dest = String::with_capacity(src.len());
+
+    for character in src.chars() {
+        match character {
+            '"' | '\\' | '\n' | '\r' | '\t' => {
+                dest.extend(character.escape_default());
+            }
+            _ => dest.push(character),
+        }
+    }
+
+    dest
+}