pgsql: Remove workaround for ancient incompatibility between readline a - Mailing list pgsql-committers

From Tom Lane
Subject pgsql: Remove workaround for ancient incompatibility between readline a
Date
Msg-id E1YWq63-0001yJ-VE@gemulon.postgresql.org
Whole thread Raw
List pgsql-committers
Remove workaround for ancient incompatibility between readline and libedit.

GNU readline defines the return value of write_history() as "zero if OK,
else an errno code".  libedit's version of that function used to have a
different definition (to wit, "-1 if error, else the number of lines
written to the file").  We tried to work around that by checking whether
errno had become nonzero, but this method has never been kosher according
to the published API of either library.  It's reportedly completely broken
in recent Ubuntu releases: psql bleats about "No such file or directory"
when saving ~/.psql_history, even though the write worked fine.

However, libedit has been following the readline definition since somewhere
around 2006, so it seems all right to finally break compatibility with
ancient libedit releases and trust that the return value is what readline
specifies.  (I'm not sure when the various Linux distributions incorporated
this fix, but I did find that OS X has been shipping fixed versions since
10.5/Leopard.)

If anyone is still using such an ancient libedit, they will find that psql
complains it can't write ~/.psql_history at exit, even when the file was
written correctly.  This is no worse than the behavior we're fixing for
current releases.

Back-patch to all supported branches.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/df9ebf1eeaf98481e00cd77bf6056d42310731b7

Modified Files
--------------
src/bin/psql/input.c |   17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)


pgsql-committers by date:

Previous
From: Tom Lane
Date:
Subject: pgsql: Remove workaround for ancient incompatibility between readline a
Next
From: Tom Lane
Date:
Subject: pgsql: Remove workaround for ancient incompatibility between readline a