Issue #17225: JSON decoder now counts columns in the first line starting

with 1, as in other lines.

Doc/library/json.rst

@@ -102,7 +102,7 @@ Using json.tool from the shell to validate and pretty-print::
         "json": "obj"
     }
     $ echo '{1.2:3.4}' | python -mjson.tool
-    Expecting property name enclosed in double quotes: line 1 column 1 (char 1)
+    Expecting property name enclosed in double quotes: line 1 column 2 (char 1)
 
 .. highlight:: python3
 

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 enclosed in double quotes: line 1 column 2 (char 2)
+    Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
 """
 __version__ = '2.0.9'
 __all__ = [

Lib/json/decoder.py

@@ -32,7 +32,7 @@ def linecol(doc, pos):
         newline = '\n'
     lineno = doc.count(newline, 0, pos) + 1
     if lineno == 1:
-        colno = pos
+        colno = pos + 1
     else:
         colno = pos - doc.rindex(newline, 0, pos)
     return lineno, colno

Lib/json/tool.py

@@ -7,7 +7,7 @@ Usage::
         "json": "obj"
     }
     $ echo '{ 1.2:3.4}' | python -m json.tool
-    Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
+    Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
 
 """
 import sys

Misc/NEWS

@@ -227,6 +227,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #17225: JSON decoder now counts columns in the first line starting
+  with 1, as in other lines.
+
 - Issue #13700: Fix byte/string handling in imaplib authentication when an
   authobject is specified.