[glib] date: Amend some comments about the month names

[Philip Withnall <pwithnall src gnome org>]

commit 2c15b903e217beca02217ad20ca3c5fefea99649
Author: Rafal Luzynski <digitalfreak lingonborough com>
Date:   Wed Feb 28 12:13:15 2018 +0100

    date: Amend some comments about the month names
    
    Some source code comments amended to avoid possible future confusion.
    It has been explained that a month name is used in a genitive case
    only if it is required by the language rules. Also it has been
    explained that %OB is also supported by other platforms (e.g., BSD)
    but for this test we are focused on glibc 2.27 vs. Windows.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=749206

 glib/gdate.c      |  6 +++++-
 glib/tests/date.c | 13 +++++++++----
 2 files changed, 14 insertions(+), 5 deletions(-)
---
diff --git a/glib/gdate.c b/glib/gdate.c
index 8ff224b60..0f30a5934 100644
--- a/glib/gdate.c
+++ b/glib/gdate.c
@@ -984,10 +984,14 @@ g_date_fill_parse_tokens (const gchar *str, GDateParseTokens *pt)
       i = 1;
       while (i < 13)
         {
-          /* Here month names will be in a genitive case.
+          /* Here month names may be in a genitive case if the language
+           * grammatical rules require it.
            * Examples of how January may look in some languages:
            * Catalan: "de gener", Croatian: "siječnja", Polish: "stycznia",
            * Upper Sorbian: "januara".
+           * Note that most of the languages can't or don't use the the
+           * genitive case here so they use nominative everywhere.
+           * For example, English always uses "January".
            */
           if (long_month_names[i] != NULL) 
             {
diff --git a/glib/tests/date.c b/glib/tests/date.c
index 4c2585281..b3d78347d 100644
--- a/glib/tests/date.c
+++ b/glib/tests/date.c
@@ -187,15 +187,20 @@ test_month_names (void)
 
   g_test_bug ("749206");
 
-  /* This test can only work (on non-Windows platforms) if libc supports the %OB
-   * (etc.) format placeholders. If it doesn’t, strftime() (and hence
+  /* This test can only work (on non-Windows platforms) if libc supports
+   * the %OB (etc.) format placeholders. If it doesn’t, strftime() (and hence
    * g_date_strftime()) will return the placeholder unsubstituted.
    * g_date_strftime() explicitly documents that it doesn’t provide any more
    * format placeholders than the system strftime(), so we should skip the test
    * in that case. If people need %OB support, they should depend on a suitable
-   * version of libc, or use g_date_time_format(). */
+   * version of libc, or use g_date_time_format(). Note: a test for a support
+   * of _NL_ABALTMON_* is not strictly the same as checking for %OB support.
+   * Some platforms (BSD, OS X) support %OB while _NL_ABALTMON_* and %Ob
+   * are supported only by glibc 2.27 and newer. But we don’t care about BSD
+   * here, the aim of this test is to make sure that our custom implementation
+   * for Windows works the same as glibc 2.27 native implementation. */
 #if !defined(HAVE_LANGINFO_ABALTMON) && !defined(G_OS_WIN32)
-  g_test_skip ("libc doesn’t support alternate month names");
+  g_test_skip ("libc doesn’t support all alternative month names");
 #else
 
 #define TEST_DATE(d,m,y,f,o)                                    \