Issue #5067: improve some json error messages.

Patch by Serhiy Storchaka.

3 files changed, 9 insertions, 7 deletions

diff --git a/Lib/json/__init__.py b/Lib/json/__init__.py
index ba2bc1d..725b5cd 100644
--- a/Lib/json/__init__.py
+++ b/Lib/json/__init__.py
@@ -97,7 +97,7 @@ Using json.tool from the shell to validate and pretty-print::
         "json": "obj"
     }
     $ echo '{ 1.2:3.4}' | python -m json.tool
-    Expecting property name: line 1 column 2 (char 2)
+    Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
 """
 __version__ = '2.0.9'
 __all__ = [
diff --git a/Lib/json/decoder.py b/Lib/json/decoder.py
index e7c0539..07fd696 100644
--- a/Lib/json/decoder.py
+++ b/Lib/json/decoder.py
@@ -172,7 +172,8 @@ def JSONObject(s_and_end, strict, scan_once, object_hook, object_pairs_hook,
                 pairs = object_hook(pairs)
             return pairs, end + 1
         elif nextchar != '"':
-            raise ValueError(errmsg("Expecting property name", s, end))
+            raise ValueError(errmsg(
+                "Expecting property name enclosed in double quotes", s, end))
     end += 1
     while True:
         key, end = scanstring(s, end, strict)
@@ -182,7 +183,7 @@ def JSONObject(s_and_end, strict, scan_once, object_hook, object_pairs_hook,
         if s[end:end + 1] != ':':
             end = _w(s, end).end()
             if s[end:end + 1] != ':':
-                raise ValueError(errmsg("Expecting : delimiter", s, end))
+                raise ValueError(errmsg("Expecting ':' delimiter", s, end))
         end += 1
 
         try:
@@ -210,12 +211,13 @@ def JSONObject(s_and_end, strict, scan_once, object_hook, object_pairs_hook,
         if nextchar == '}':
             break
         elif nextchar != ',':
-            raise ValueError(errmsg("Expecting , delimiter", s, end - 1))
+            raise ValueError(errmsg("Expecting ',' delimiter", s, end - 1))
         end = _w(s, end).end()
         nextchar = s[end:end + 1]
         end += 1
         if nextchar != '"':
-            raise ValueError(errmsg("Expecting property name", s, end - 1))
+            raise ValueError(errmsg(
+                "Expecting property name enclosed in double quotes", s, end - 1))
     if object_pairs_hook is not None:
         result = object_pairs_hook(pairs)
         return result, end
@@ -249,7 +251,7 @@ def JSONArray(s_and_end, scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
         if nextchar == ']':
             break
         elif nextchar != ',':
-            raise ValueError(errmsg("Expecting , delimiter", s, end))
+            raise ValueError(errmsg("Expecting ',' delimiter", s, end))
         try:
             if s[end] in _ws:
                 end += 1
diff --git a/Lib/json/tool.py b/Lib/json/tool.py
index 6d6558a..1adea31 100644
--- a/Lib/json/tool.py
+++ b/Lib/json/tool.py
@@ -7,7 +7,7 @@ Usage::
         "json": "obj"
     }
     $ echo '{ 1.2:3.4}' | python -m json.tool
-    Expecting property name: line 1 column 2 (char 2)
+    Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
 
 """
 import sys