From df9ebf1eeaf98481e00cd77bf6056d42310731b7 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 14 Mar 2015 13:43:00 -0400 Subject: [PATCH] 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. --- src/bin/psql/input.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/src/bin/psql/input.c b/src/bin/psql/input.c index 373013955f..d52a334797 100644 --- a/src/bin/psql/input.c +++ b/src/bin/psql/input.c @@ -382,6 +382,7 @@ static bool saveHistory(char *fname, int max_lines) { #ifdef USE_READLINE + int errnum; /* * Suppressing the write attempt when HISTFILE is set to /dev/null may @@ -405,10 +406,6 @@ saveHistory(char *fname, int max_lines) * history from other concurrent sessions (although there are still * race conditions when two sessions exit at about the same time). If * we don't have those functions, fall back to write_history(). - * - * Note: return value of write_history is not standardized across GNU - * readline and libedit. Therefore, check for errno becoming set to - * see if the write failed. Similarly for append_history. */ #if defined(HAVE_HISTORY_TRUNCATE_FILE) && defined(HAVE_APPEND_HISTORY) { @@ -430,9 +427,8 @@ saveHistory(char *fname, int max_lines) nlines = Min(max_lines, history_lines_added); else nlines = history_lines_added; - errno = 0; - (void) append_history(nlines, fname); - if (errno == 0) + errnum = append_history(nlines, fname); + if (errnum == 0) return true; } #else /* don't have append support */ @@ -441,15 +437,14 @@ saveHistory(char *fname, int max_lines) if (max_lines >= 0) stifle_history(max_lines); /* ... and overwrite file. Tough luck for concurrent sessions. */ - errno = 0; - (void) write_history(fname); - if (errno == 0) + errnum = write_history(fname); + if (errnum == 0) return true; } #endif psql_error("could not save history to file \"%s\": %s\n", - fname, strerror(errno)); + fname, strerror(errnum)); } #endif -- 2.40.0