[PATCH v2] xdiff/xmerge: fix memory leak in xdl_merge

[Patrick Steinhardt <ps@pks.im>]

When building the script for the second file that is to be merged
we have already allocated memory for data structures related to
the first file. When we encounter an error in building the second
script we only free allocated memory related to the second file
before erroring out.

Fix this memory leak by also releasing allocated memory related
to the first file.

Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 xdiff/xmerge.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/xdiff/xmerge.c b/xdiff/xmerge.c
index d98f430..f338ad6 100644
--- a/xdiff/xmerge.c
+++ b/xdiff/xmerge.c
@@ -641,8 +641,11 @@ int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
 	result->ptr = NULL;
 	result->size = 0;
 
-	if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0 ||
-			xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
+	if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0) {
+		return -1;
+	}
+	if (xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
+		xdl_free_env(&xe1);
 		return -1;
 	}
 	if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
@@ -654,6 +657,8 @@ int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
 	if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
 	    xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
 	    xdl_build_script(&xe2, &xscr2) < 0) {
+		xdl_free_script(xscr1);
+		xdl_free_env(&xe1);
 		xdl_free_env(&xe2);
 		return -1;
 	}
-- 
2.7.1