Fix portability issues in datetime parsing.

datetime.c's parsing logic has assumed that strtod() will accept
a string that looks like ".", which it does in glibc, but not on
some less-common platforms such as AIX.  The result of this was
that datetime fields like "123." would be accepted on some platforms
but not others; which is a sufficiently odd case that it's not that
surprising we've heard no field complaints.  But commit e39f99046
extended that assumption to new places, and happened to add a test
case that exposed the platform dependency.  Remove this dependency
by special-casing situations without any digits after the decimal
point.

(Again, this is in part a pre-existing bug but I don't feel a
compulsion to back-patch.)

Also, rearrange e39f99046's changes in formatting.c to avoid a
Coverity complaint that we were copying an uninitialized field.

Discussion: https://postgr.es/m/1592893.1648969747@sss.pgh.pa.us

2 files changed, 43 insertions, 0 deletions

diff --git a/src/test/regress/expected/interval.out b/src/test/regress/expected/interval.out
index 86c8d4bc990..03f77c01dcf 100644
--- a/src/test/regress/expected/interval.out
+++ b/src/test/regress/expected/interval.out
@@ -908,6 +908,41 @@ select  interval 'P0002'                  AS "year only",
  2 years   | 2 years 10 mons | 2 years 10 mons 15 days | 2 years 00:00:01    | 2 years 10 mons 00:00:01 | 2 years 10 mons 15 days 00:00:01 | 10:00:00  | 10:30:00
 (1 row)
 
+-- Check handling of fractional fields in ISO8601 format.
+select interval 'P1Y0M3DT4H5M6S';
+        interval        
+------------------------
+ 1 year 3 days 04:05:06
+(1 row)
+
+select interval 'P1.0Y0M3DT4H5M6S';
+        interval        
+------------------------
+ 1 year 3 days 04:05:06
+(1 row)
+
+select interval 'P1.1Y0M3DT4H5M6S';
+           interval           
+------------------------------
+ 1 year 1 mon 3 days 04:05:06
+(1 row)
+
+select interval 'P1.Y0M3DT4H5M6S';
+        interval        
+------------------------
+ 1 year 3 days 04:05:06
+(1 row)
+
+select interval 'P.1Y0M3DT4H5M6S';
+       interval        
+-----------------------
+ 1 mon 3 days 04:05:06
+(1 row)
+
+select interval 'P.Y0M3DT4H5M6S';  -- error
+ERROR:  invalid input syntax for type interval: "P.Y0M3DT4H5M6S"
+LINE 1: select interval 'P.Y0M3DT4H5M6S';
+                        ^
 -- test a couple rounding cases that changed since 8.3 w/ HAVE_INT64_TIMESTAMP.
 SET IntervalStyle to postgres_verbose;
 select interval '-10 mons -3 days +03:55:06.70';
diff --git a/src/test/regress/sql/interval.sql b/src/test/regress/sql/interval.sql
index f05055e03a9..97d33a13236 100644
--- a/src/test/regress/sql/interval.sql
+++ b/src/test/regress/sql/interval.sql
@@ -312,6 +312,14 @@ select  interval 'P0002'                  AS "year only",
         interval 'PT10'                   AS "hour only",
         interval 'PT10:30'                AS "hour minute";
 
+-- Check handling of fractional fields in ISO8601 format.
+select interval 'P1Y0M3DT4H5M6S';
+select interval 'P1.0Y0M3DT4H5M6S';
+select interval 'P1.1Y0M3DT4H5M6S';
+select interval 'P1.Y0M3DT4H5M6S';
+select interval 'P.1Y0M3DT4H5M6S';
+select interval 'P.Y0M3DT4H5M6S';  -- error
+
 -- test a couple rounding cases that changed since 8.3 w/ HAVE_INT64_TIMESTAMP.
 SET IntervalStyle to postgres_verbose;
 select interval '-10 mons -3 days +03:55:06.70';