patch 8.0.0605: the quickfix cached buffer may become invalidv8.0.0605

Problem:    The buffer that quickfix caches for performance may become
            invalid. (Daniel Hahler)
Solution:   Reset qf_last_bufref in qf_init_ext(). (Daniel Hahler,
            closes #1728, closes #1676)

2 files changed, 13 insertions, 7 deletions

diff --git a/src/quickfix.c b/src/quickfix.c
index 9626cfa43..ce21661a6 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -158,6 +158,13 @@ static qf_info_T *ll_get_or_alloc_list(win_T *);
 #define GET_LOC_LIST(wp) (IS_LL_WINDOW(wp) ? wp->w_llist_ref : wp->w_llist)
 
 /*
+ * Looking up a buffer can be slow if there are many.  Remember the last one
+ * to make this a lot faster if there are multiple matches in the same file.
+ */
+static char_u *qf_last_bufname = NULL;
+static bufref_T  qf_last_bufref = {NULL, 0};
+
+/*
  * Read the errorfile "efile" into memory, line by line, building the error
  * list. Set the error list's title to qf_title.
  * Return -1 for error, number of errors for success.
@@ -1151,6 +1158,10 @@ qf_init_ext(
     int		    retval = -1;	/* default: return error flag */
     int		    status;
 
+    /* Do not used the cached buffer, it may have been wiped out. */
+    vim_free(qf_last_bufname);
+    qf_last_bufname = NULL;
+
     vim_memset(&state, 0, sizeof(state));
     vim_memset(&fields, 0, sizeof(fields));
 #ifdef FEAT_MBYTE
@@ -1660,13 +1671,6 @@ copy_loclist(win_T *from, win_T *to)
 }
 
 /*
- * Looking up a buffer can be slow if there are many.  Remember the last one
- * to make this a lot faster if there are multiple matches in the same file.
- */
-static char_u *qf_last_bufname = NULL;
-static bufref_T  qf_last_bufref = {NULL, 0};
-
-/*
  * Get buffer number for file "directory/fname".
  * Also sets the b_has_qf_entry flag.
  */
diff --git a/src/version.c b/src/version.c
index bc80ace74..2c5aa06fd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    605,
+/**/
     604,
 /**/
     603,