Merge remote-tracking branch 'origin/topic/awelzel/fix-assert-cond-twice'

* origin/topic/awelzel/fix-assert-cond-twice:
  Stmt: Fix assert evaluating cond twice

(cherry picked from commit 6867eda621)

src/Stmt.cc

@@ -1644,7 +1644,7 @@ ValPtr AssertStmt::Exec(Frame* f, StmtFlowType& flow) {
     bool run_result_hook = assertion_result_hook && assertion_result_hook->HasEnabledBodies();
     auto assert_result = cond->Eval(f)->AsBool();
 
-    if ( ! cond->Eval(f)->AsBool() || run_result_hook ) {
+    if ( ! assert_result || run_result_hook ) {
         zeek::StringValPtr msg_val = zeek::val_mgr->EmptyString();
 
         if ( msg ) {

testing/btest/Baseline/language.assert-hook-8/.stderr

@@ -0,0 +1 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.

testing/btest/Baseline/language.assert-hook-8/out

@@ -0,0 +1,6 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+zeek_init
+returning true
+assertion_result, T, always_true(), always true, <...>/assert-hook.zeek, 23
+returning false
+assertion_result, F, always_false(), always false, <...>/assert-hook.zeek, 24

testing/btest/language/assert-hook.zeek

@@ -196,3 +196,31 @@ event zeek_done()
 	assert 2 + 2 == 5, "this is false";
 	print "not reached";
 	}
+
+@TEST-START-NEXT
+# Ensure cond is only evaluated once.
+hook assertion_result(result: bool, cond: string, msg: string, bt: Backtrace)
+	{
+	print "assertion_result", result, cond, msg, bt[0]$file_location, bt[0]$line_location;
+	break;
+	}
+
+function always_true(): bool
+	{
+	print "returning true";
+	return T;
+	}
+
+function always_false(): bool
+	{
+	print "returning false";
+	return F;
+	}
+
+event zeek_init()
+	{
+	print "zeek_init";
+	assert always_true(), "always true";
+	assert always_false(), "always false";
+	print "not reached";
+	}