From 67e7f4a1a64fd0e303082ce855cba63762dac2ed Mon Sep 17 00:00:00 2001
From: Gabriel Gonzalez <Gabriel439@gmail.com>
Date: Wed, 22 Jul 2020 18:23:39 -0700
Subject: [PATCH] Single-quote more pathological strings

See: https://github.com/dhall-lang/dhall-haskell/issues/1939
---
 src/Data/Aeson/Yaml.hs       | 25 +++++++++++++++++++++----
 test/Test/Data/Aeson/Yaml.hs | 12 +++++++++---
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/src/Data/Aeson/Yaml.hs b/src/Data/Aeson/Yaml.hs
index c9070c3..4280d67 100644
--- a/src/Data/Aeson/Yaml.hs
+++ b/src/Data/Aeson/Yaml.hs
@@ -122,24 +122,38 @@ encodeText canMultiline alwaysQuote level s
   -- s is a value, not a map key, and contains newlines; can be inserted
   -- literally with `|` syntax
   | canMultiline && "\n" `Text.isSuffixOf` s = encodeLines level (Text.lines s)
-  -- s is a number, date, or boolString; single-quote
-  | Text.all isNumberOrDateRelated s || isBoolString = singleQuote
-  -- s should be quoted, AND s is not unsafe; single-quote
-  | alwaysQuote && unquotable = singleQuote
+
+  | shouldSingleQuote = singleQuote
+
   -- s should be quoted, OR s might be unsafe; double-quote
   | alwaysQuote || not unquotable = bl $ Data.Aeson.encode s
+
   -- otherwise; no quotes
   | otherwise = noQuote
   where
     noQuote = b (Text.Encoding.encodeUtf8 s)
+
+    shouldSingleQuote =
+            (Text.all isNumberOrDateRelated s && Text.any isDigit s)
+        ||  isBoolString
+        ||  Text.isPrefixOf " " s
+        ||  Text.isSuffixOf " " s
+            -- Quote if the string looks like a key
+        ||  Text.isInfixOf ":" s
+            -- s should be quoted, AND s is not unsafe; single-quote
+        ||  (alwaysQuote && unquotable)
+
     singleQuote = bs "'" <> noQuote <> bs "'"
+
     headS = Text.head s
+
     unquotable -- s is unquotable if all are True
      =
       s /= "" && -- s is not empty
       Text.all isAllowed s && -- s consists of acceptable chars
       (Data.Char.isAlpha headS || -- head of s is a char in A-Z or a-z or indicates a filepath
        headS == '/')
+
     isBoolString
       | Text.length s > 5 = False
       | otherwise =
@@ -147,11 +161,14 @@ encodeText canMultiline alwaysQuote level s
           "true" -> True
           "false" -> True
           _ -> False
+
     isSafeAscii c =
       (c >= 'a' && c <= 'z') ||
       (c >= 'A' && c <= 'Z') ||
       (c >= '0' && c <= '9') || c == '/' || c == '_' || c == '.' || c == '='
+
     isNumberOrDateRelated c = isDigit c || c == '.' || c == 'e' || c == '-'
+
     isAllowed c = isSafeAscii c || c == '-' || c == ':' || c == ' '
 
 encodeLines :: Int -> [Text] -> Builder
diff --git a/test/Test/Data/Aeson/Yaml.hs b/test/Test/Data/Aeson/Yaml.hs
index 55c5fc4..0eb52a0 100644
--- a/test/Test/Data/Aeson/Yaml.hs
+++ b/test/Test/Data/Aeson/Yaml.hs
@@ -59,24 +59,29 @@ tcDataTypes =
    "piString": "3.14",
    "expString": "1e3",
    "leadingSpace" : " leading space",
+   "trailingSpace" : "trailing space ",
+   "colon" : "colon:",
    "leadingSymbol" : "!leading symbol",
    "asteriskString": "*",
    "multiLine": "The first line is followed by the\nsecond line\n",
    "multiLineWithSpaces": "         This has extra\n     spaces at the beginning\n",
    "notMultiline": "This won't be\nmulti-lined",
    "list": ["foo", "bar", "baz"],
-   "listEmpty": []
+   "listEmpty": [],
+   "e": null
 }
 |]
     , tcOutput =
         [s|asteriskString: "*"
 boolString: 'true'
+colon: 'colon:'
 dateString: '2038-01-19'
+e: null
 emptyObject: {}
 expString: '1e3'
 isFalse: false
 isTrue: true
-leadingSpace: " leading space"
+leadingSpace: ' leading space'
 leadingSymbol: "!leading symbol"
 list:
   - foo
@@ -94,6 +99,7 @@ nullValue: null
 numberString: '12345'
 piString: '3.14'
 "quoted ! key": true
+trailingSpace: 'trailing space '
 |]
     , tcAlwaysQuote = False
     }
@@ -181,7 +187,7 @@ spec:
         - command:
             - /data/bin/foo
             - "--port=7654"
-          image: ubuntu:latest
+          image: 'ubuntu:latest'
           name: "{{ .Release.Name }}-container"
           ports:
             - containerPort: 7654