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commit    c4c29e0d154c88c58738ee1e257da84f2bf5786b
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Mon Jan 25 01:58:48 2010 +0000
First released in: 9.0.0, 7.4.28, 8.0.24, 8.1.20, 8.2.16, 8.3.10, 8.4.3

    Apply Tcl_Init() to the "hold" interpreter created by pltcl.
    
    You might think this is unnecessary since that interpreter is never used
    to run code --- but it turns out that's wrong.  As of Tcl 8.5, the "clock"
    command (alone among builtin Tcl commands) is partially implemented by
    loaded-on-demand Tcl code, which means that it fails if there's not
    unknown-command support, and also that it's impossible to run it directly
    in a safe interpreter.  The way they get around the latter is that
    Tcl_CreateSlave() automatically sets up an alias command that forwards any
    execution of "clock" in a safe slave interpreter to its parent interpreter.
    Thus, when attempting to execute "clock" in trusted pltcl, the command
    actually executes in the "hold" interpreter, where it will fail if
    unknown-command support hasn't been introduced by sourcing the standard
    init.tcl script, which is done by Tcl_Init().  (This is a pretty dubious
    design decision on the Tcl boys' part, if you ask me ... but they didn't.)
    
    Back-patch all the way.  It's not clear that anyone would try to use ancient
    versions of pltcl with a recent Tcl, but it's not clear they wouldn't, either.
    Also add a regression test using "clock", in branches that have regression
    test support for pltcl.
    
    Per recent trouble report from Kyle Bateman.


 src/pl/tcl/pltcl.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 6b5004b7892..a6a3a93eb50 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -31,7 +31,7 @@
  *	  ENHANCEMENTS, OR MODIFICATIONS.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/tcl/pltcl.c,v 1.94.4.2 2008/06/17 00:53:13 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/tcl/pltcl.c,v 1.94.4.3 2010/01/25 01:58:48 tgl Exp $
  *
  **********************************************************************/
 
@@ -246,9 +246,12 @@ pltcl_init(void)
 	 ************************************************************/
 	if ((pltcl_hold_interp = Tcl_CreateInterp()) == NULL)
 		elog(ERROR, "could not create \"hold\" interpreter");
+	if (Tcl_Init(pltcl_hold_interp) == TCL_ERROR)
+		elog(ERROR, "could not initialize \"hold\" interpreter");
 
 	/************************************************************
-	 * Create the two interpreters
+	 * Create the two slave interpreters.  Note: Tcl automatically does
+	 * Tcl_Init on the normal slave, and it's not wanted for the safe slave.
 	 ************************************************************/
 	if ((pltcl_norm_interp =
 		 Tcl_CreateSlave(pltcl_hold_interp, "norm", 0)) == NULL)


[parent: ce95d0f14d2a]