From dce343e9261cb7670e13912b07e52b5354c7572c Mon Sep 17 00:00:00 2001
From: Matti Niemenmaa <matti.niemenmaa+git@iki.fi>
Date: Mon, 1 Oct 2018 11:58:57 +0300
Subject: [PATCH] Avoid panic on pretty string ending in single quote

Fixes #262.
---
 src/ser.rs                                         |  4 ++++
 test-suite/tests/valid.rs                          |  4 ++++
 test-suite/tests/valid/quote-surrounded-value.json | 10 ++++++++++
 test-suite/tests/valid/quote-surrounded-value.toml |  2 ++
 4 files changed, 20 insertions(+)
 create mode 100644 test-suite/tests/valid/quote-surrounded-value.json
 create mode 100644 test-suite/tests/valid/quote-surrounded-value.toml

diff --git a/src/ser.rs b/src/ser.rs
index 9d989db..9f36f59 100644
--- a/src/ser.rs
+++ b/src/ser.rs
@@ -585,6 +585,10 @@ impl<'a> Serializer<'a> {
                     }
                 }
             }
+            if can_be_pretty && found_singles > 0 && value.ends_with('\'') {
+                // We cannot escape the ending quote so we must use """
+                can_be_pretty = false;
+            }
             if !can_be_pretty {
                 debug_assert!(ty != Type::OnelineTripple);
                 return Repr::Std(ty);
diff --git a/test-suite/tests/valid.rs b/test-suite/tests/valid.rs
index d032ba5..7c1691c 100644
--- a/test-suite/tests/valid.rs
+++ b/test-suite/tests/valid.rs
@@ -250,3 +250,7 @@ test!(table_array_nest_no_keys,
 test!(dotted_keys,
       include_str!("valid/dotted-keys.toml"),
       include_str!("valid/dotted-keys.json"));
+
+test!(quote_surrounded_value,
+      include_str!("valid/quote-surrounded-value.toml"),
+      include_str!("valid/quote-surrounded-value.json"));
diff --git a/test-suite/tests/valid/quote-surrounded-value.json b/test-suite/tests/valid/quote-surrounded-value.json
new file mode 100644
index 0000000..84495cf
--- /dev/null
+++ b/test-suite/tests/valid/quote-surrounded-value.json
@@ -0,0 +1,10 @@
+{
+  "double": {
+    "type": "string",
+    "value": "\"double quotes here\""
+  },
+  "single": {
+    "type": "string",
+    "value": "'single quotes here'"
+  }
+}
diff --git a/test-suite/tests/valid/quote-surrounded-value.toml b/test-suite/tests/valid/quote-surrounded-value.toml
new file mode 100644
index 0000000..dc8697e
--- /dev/null
+++ b/test-suite/tests/valid/quote-surrounded-value.toml
@@ -0,0 +1,2 @@
+double = '"double quotes here"'
+single = "'single quotes here'"