fix bugs with pretty

src/ser.rs

@@ -450,14 +450,18 @@ impl<'a> Serializer<'a> {
         if ok {
             drop(write!(self.dst, "{}", key));
         } else {
-            self.emit_str(key)?;
+            self.emit_str(key, true)?;
         }
         Ok(())
     }
 
-    fn emit_str(&mut self, value: &str) -> Result<(), Error> {
-        let do_pretty = if self.settings.pretty_string {
+    fn emit_str(&mut self, value: &str, is_key: bool) -> Result<(), Error> {
+        let do_pretty = if !is_key && self.settings.pretty_string {
+            // do pretty only if the block contains at least one newline
             value.contains('\n') 
+                // but not if it contains any of these, as they are not
+                // representable
+                && !value.contains("'''")
         } else {
             false
         };
@@ -466,31 +470,21 @@ impl<'a> Serializer<'a> {
         } else {
             drop(write!(self.dst, "\""));
         }
-        for ch in value.chars() {
-            match ch {
-                '\u{8}' => drop(write!(self.dst, "\\b")),
-                '\u{9}' => drop(write!(self.dst, "\\t")),
-                '\u{a}' => {
-                    if do_pretty {
-                        drop(write!(self.dst, "\n"));
-                    } else {
-                        drop(write!(self.dst, "\\n"));
-                    }
-                },
-                '\u{c}' => drop(write!(self.dst, "\\f")),
-                '\u{d}' => drop(write!(self.dst, "\\r")),
-                '\u{22}' => {
-                    if do_pretty {
-                        drop(write!(self.dst, "\""))
-                    } else {
-                        drop(write!(self.dst, "\\\""))
-                    }
-                },
-                '\u{5c}' => drop(write!(self.dst, "\\\\")),
-                c if c < '\u{1f}' => {
-                    drop(write!(self.dst, "\\u{:04X}", ch as u32))
+        if do_pretty {
+            drop(write!(self.dst, "{}", value));
+        } else {
+            for ch in value.chars() {
+                match ch {
+                    '\u{8}' => drop(write!(self.dst, "\\b")),
+                    '\u{9}' => drop(write!(self.dst, "\\t")),
+                    '\u{a}' => drop(write!(self.dst, "\\n")),
+                    '\u{c}' => drop(write!(self.dst, "\\f")),
+                    '\u{d}' => drop(write!(self.dst, "\\r")),
+                    '\u{22}' => drop(write!(self.dst, "\\\"")),
+                    '\u{5c}' => drop(write!(self.dst, "\\\\")),
+                    c if c < '\u{1f}' => drop(write!(self.dst, "\\u{:04X}", ch as u32)),
+                    ch => drop(write!(self.dst, "{}", ch)),
                 }
-                ch => drop(write!(self.dst, "{}", ch)),
             }
         }
         if do_pretty {
@@ -651,7 +645,7 @@ impl<'a, 'b> ser::Serializer for &'b mut Serializer<'a> {
 
     fn serialize_str(mut self, value: &str) -> Result<(), Self::Error> {
         self.emit_key("string")?;
-        self.emit_str(value)?;
+        self.emit_str(value, false)?;
         if let State::Table { .. } = self.state {
             self.dst.push_str("\n");
         }

tests/pretty.rs

@@ -166,3 +166,22 @@ fn pretty_no_string() {
     }
     assert_eq!(toml, &result);
 }
+
+const PRETTY_TRICKY: &'static str = r"[example]
+text = '''
+this is the first line
+This has a ''\' in it for no reason
+this is the third line
+'''
+";
+
+#[test]
+fn pretty_tricky() {
+    let toml = PRETTY_TRICKY;
+    let value: toml::Value = toml::from_str(toml).unwrap();
+    let mut result = String::with_capacity(128);
+    value.serialize(&mut toml::Serializer::pretty(&mut result)).unwrap();
+    println!("EXPECTED:\n{}", toml);
+    println!("\nRESULT:\n{}", result);
+    assert_eq!(toml, &result);
+}

tests/valid.rs

@@ -1,7 +1,9 @@
 extern crate toml;
+extern crate serde;
 extern crate serde_json;
 
-use toml::Value as Toml;
+use toml::{Value as Toml, to_string_pretty};
+use serde::ser::Serialize;
 use serde_json::Value as Json;
 
 fn to_json(toml: toml::Value) -> Json {
@@ -40,10 +42,52 @@ fn to_json(toml: toml::Value) -> Json {
     }
 }
 
-fn run(toml: &str, json: &str) {
-    println!("parsing:\n{}", toml);
-    let toml: Toml = toml.parse().unwrap();
-    let json: Json = json.parse().unwrap();
+fn run_pretty(toml: Toml) {
+    // Assert toml == json
+    println!("### pretty round trip parse.");
+    
+    // standard pretty
+    let toml_raw = to_string_pretty(&toml).expect("to string");
+    let toml2 = toml_raw.parse().expect("from string");
+    assert_eq!(toml, toml2);
+
+    // pretty with indent 2
+    let mut result = String::with_capacity(128);
+    {
+        let mut serializer = toml::Serializer::pretty(&mut result);
+        serializer.pretty_array_indent(2);
+        toml.serialize(&mut serializer).expect("to string");
+    }
+    assert_eq!(toml, result.parse().expect("from str"));
+    result.clear();
+    {
+        let mut serializer = toml::Serializer::new(&mut result);
+        serializer.pretty_array_trailing_comma(false);
+        toml.serialize(&mut serializer).expect("to string");
+    }
+    assert_eq!(toml, result.parse().expect("from str"));
+    result.clear();
+    {
+        let mut serializer = toml::Serializer::pretty(&mut result);
+        serializer.pretty_string(false);
+        toml.serialize(&mut serializer).expect("to string");
+        assert_eq!(toml, toml2);
+    }
+    assert_eq!(toml, result.parse().expect("from str"));
+    result.clear();
+    {
+        let mut serializer = toml::Serializer::pretty(&mut result);
+        serializer.pretty_array(false);
+        toml.serialize(&mut serializer).expect("to string");
+        assert_eq!(toml, toml2);
+    }
+    assert_eq!(toml, result.parse().expect("from str"));
+}
+
+fn run(toml_raw: &str, json_raw: &str) {
+    println!("parsing:\n{}", toml_raw);
+    let toml: Toml = toml_raw.parse().unwrap();
+    let json: Json = json_raw.parse().unwrap();
 
     // Assert toml == json
     let toml_json = to_json(toml.clone());
@@ -56,6 +100,7 @@ fn run(toml: &str, json: &str) {
     println!("round trip parse: {}", toml);
     let toml2 = toml.to_string().parse().unwrap();
     assert_eq!(toml, toml2);
+    run_pretty(toml);
 }
 
 macro_rules! test( ($name:ident, $toml:expr, $json:expr) => (