From: Emden R. Gansner <erg@alum.mit.edu>
Date: Wed, 18 Feb 2015 20:50:55 +0000 (-0500)
Subject: Fix bug where string constants are allocated in temp memory during
X-Git-Tag: TRAVIS_CI_BUILD_EXPERIMENTAL~118^2~2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d01ad2994cf06a3b16ff2c564927dc5416df1235;p=graphviz

Fix bug where string constants are allocated in temp memory during
compilation, but temp memory is freed each time an evaluation is done.
---

diff --git a/lib/expr/exparse.y b/lib/expr/exparse.y
index 306167f80..02d45fea1 100644
--- a/lib/expr/exparse.y
+++ b/lib/expr/exparse.y
@@ -641,6 +641,14 @@ expr		:	'(' expr ')'
 			if (!expr.program->errors && $1->op == CONSTANT && $3->op == CONSTANT)
 			{
 				$$->data.constant.value = exeval(expr.program, $$, NiL);
+				/* If a constant string, re-allocate from program heap. This is because the
+				 * value was constructed from string operators, which create a value in the 
+				 * temporary heap, which is cleared when exeval is called again. 
+				 */
+				if ($$->type == STRING) {
+					$$->data.constant.value.string =
+						vmstrdup(expr.program->vm, $$->data.constant.value.string);
+				}
 				$$->binary = 0;
 				$$->op = CONSTANT;
 				exfreenode(expr.program, $1);