From e8557caace66b058e3048de7eff954baaa6c0493 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 6 Sep 2017 23:05:35 -0400
Subject: parse: Don't reorder or remove tests with potential side effects

-empty and -xtype may have side effects like reporting permission
errors, which even affect the exit status of bfs.  We shouldn't remove
these effects without -Ofast.
---
 parse.c                      | 24 +++++++++++++++++++++---
 tests.sh                     |  8 ++++++++
 tests/test_xtype_reorder.out |  0
 3 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 tests/test_xtype_reorder.out

diff --git a/parse.c b/parse.c
index 811ec5a..f6cde7a 100644
--- a/parse.c
+++ b/parse.c
@@ -1003,10 +1003,20 @@ static struct expr *parse_depth_limit(struct parser_state *state, int is_min, in
  */
 static struct expr *parse_empty(struct parser_state *state, int arg1, int arg2) {
 	struct expr *expr = parse_nullary_test(state, eval_empty);
-	if (expr) {
-		expr->cost = 2000.0;
-		expr->probability = 0.01;
+	if (!expr) {
+		return NULL;
+	}
+
+	expr->cost = 2000.0;
+	expr->probability = 0.01;
+
+	if (state->cmdline->optlevel < 4) {
+		// Since -empty attempts to open and read directories, it may
+		// have side effects such as reporting permission errors, and
+		// thus shouldn't be re-ordered without aggressive optimizations
+		expr->pure = false;
 	}
+
 	return expr;
 }
 
@@ -2103,6 +2113,14 @@ static struct expr *parse_type(struct parser_state *state, int x, int arg2) {
 
 	expr->idata = types;
 	expr->probability = probability;
+
+	if (x && state->cmdline->optlevel < 4) {
+		// Since -xtype dereferences symbolic links, it may have side
+		// effects such as reporting permission errors, and thus
+		// shouldn't be re-ordered without aggressive optimizations
+		expr->pure = false;
+	}
+
 	return expr;
 
 fail:
diff --git a/tests.sh b/tests.sh
index 620bc2a..2007d0a 100755
--- a/tests.sh
+++ b/tests.sh
@@ -374,6 +374,7 @@ gnu_tests=(
 bfs_tests=(
     test_type_multi
     test_xtype_multi
+    test_xtype_reorder
     test_perm_symbolic_trailing_comma
     test_perm_symbolic_double_comma
     test_perm_symbolic_missing_action
@@ -755,6 +756,13 @@ function test_xtype_multi() {
     bfs_diff links -xtype f,d,c 2>/dev/null
 }
 
+function test_xtype_reorder() {
+    # Make sure -xtype is not reordered in front of anything -- if -xtype runs
+    # before -links 100, it will report an ELOOP error
+    bfs_diff links -links 100 -xtype l
+    invoke_bfs links -links 100 -xtype l
+}
+
 function test_iname() {
     bfs_diff basic -iname '*F*'
 }
diff --git a/tests/test_xtype_reorder.out b/tests/test_xtype_reorder.out
new file mode 100644
index 0000000..e69de29
-- 
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