bpo-23041: update proposed changes to csv module.

python · miss-islington · Apr 12, 2023 · Nov 8, 2021 · Nov 1, 2022 · Nov 2, 2022
commit 7e92373cbba32aea398196b5287ce77193463707
diff --git a/Doc/library/csv.rst b/Doc/library/csv.rst
@@ -335,6 +335,18 @@ The :mod:`csv` module defines the following constants:
 
    Instructs :class:`reader` to perform no special processing of quote characters.
 
+.. data:: QUOTE_NOTNULL
+
+   Instructs :class:`writer` objects to quote all fields which are not
+   ``None``. If a field value is ``None`` an empty (unquoted) string
+   is written.
+
+.. data:: QUOTE_STRINGS
+
+   Instructs :class:`writer` quotes are always placed around fields
+   which are strings.  Note that ``None`` will be written as a
+   bar (unquoted) empty string.
+
 The :mod:`csv` module defines the following exception:
 
 

diff --git a/Lib/csv.py b/Lib/csv.py
@@ -8,12 +8,14 @@
                  unregister_dialect, get_dialect, list_dialects, \
                  field_size_limit, \
                  QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE, \
+                 QUOTE_STRINGS, QUOTE_NOTNULL, \
                  __doc__
 from _csv import Dialect as _Dialect
 
 from io import StringIO
 
 __all__ = ["QUOTE_MINIMAL", "QUOTE_ALL", "QUOTE_NONNUMERIC", "QUOTE_NONE",
+           "QUOTE_STRINGS", "QUOTE_NOTNULL",
            "Error", "Dialect", "__doc__", "excel", "excel_tab",
            "field_size_limit", "reader", "writer",
            "register_dialect", "get_dialect", "list_dialects", "Sniffer",

diff --git a/Lib/test/test_csv.py b/Lib/test/test_csv.py
@@ -187,6 +187,10 @@ def test_write_quoting(self):
                          quoting = csv.QUOTE_ALL)
         self._write_test(['a\nb',1], '"a\nb","1"',
                          quoting = csv.QUOTE_ALL)
+        self._write_test(['a',None,1], '"a",,1',
+                         quoting = csv.QUOTE_STRINGS)
+        self._write_test(['a',None,1], '"a",,"1"',
+                         quoting = csv.QUOTE_NOTNULL)
 
     def test_write_escape(self):
         self._write_test(['a',1,'p,q'], 'a,1,"p,q"',

diff --git a/Misc/NEWS.d/next/Library/2021-11-07-15-31-25.bpo-23041.564i32.rst b/Misc/NEWS.d/next/Library/2021-11-07-15-31-25.bpo-23041.564i32.rst
@@ -0,0 +1,2 @@
+Add QUOTE_STRINGS and QUOTE_NOTNULL to the suite of csv module quoting
+styles.
diff --git a/Modules/_csv.c b/Modules/_csv.c
@@ -74,7 +74,8 @@ typedef enum {
 } ParserState;
 
 typedef enum {
-    QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE
+    QUOTE_MINIMAL, QUOTE_ALL, QUOTE_NONNUMERIC, QUOTE_NONE,
+    QUOTE_STRINGS, QUOTE_NOTNULL
 } QuoteStyle;
 
 typedef struct {
@@ -87,6 +88,8 @@ static const StyleDesc quote_styles[] = {
     { QUOTE_ALL,        "QUOTE_ALL" },
     { QUOTE_NONNUMERIC, "QUOTE_NONNUMERIC" },
     { QUOTE_NONE,       "QUOTE_NONE" },
+    { QUOTE_STRINGS,    "QUOTE_STRINGS" },
+    { QUOTE_NOTNULL,    "QUOTE_NOTNULL" },
     { 0 }
 };
 
@@ -1259,6 +1262,12 @@ csv_writerow(WriterObj *self, PyObject *seq)
         case QUOTE_ALL:
             quoted = 1;
             break;
+        case QUOTE_STRINGS:
+            quoted = PyUnicode_Check(field);
+            break;
+        case QUOTE_NOTNULL:
+            quoted = field != Py_None;
+            break;
         default:
             quoted = 0;
             break;
@@ -1610,6 +1619,11 @@ PyDoc_STRVAR(csv_module_doc,
 "        csv.QUOTE_NONNUMERIC means that quotes are always placed around\n"
 "            fields which do not parse as integers or floating point\n"
 "            numbers.\n"
+"        csv.QUOTE_STRINGS means that quotes are always placed around\n"
+"            fields which are strings.  Note that the Python value None\n"
+"            is not a string.\n"
+"        csv.QUOTE_NOTNULL means that quotes are only placed around fields\n"
+"            that are not the Python value None.\n"
 "        csv.QUOTE_NONE means that quotes are never placed around fields.\n"
 "    * escapechar - specifies a one-character string used to escape\n"
 "        the delimiter when quoting is set to QUOTE_NONE.\n"
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Add QUOTE_STRINGS and QUOTE_NOTNULL to the suite of csv module quoting
		styles.
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