From 959ecf7f234dc0bc0cd6829b25cb0ee1481aa78a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sigbj=C3=B8rn=20Skj=C3=A6ret?= <sigbjorn.skjaeret@scala.com>
Date: Mon, 19 Jan 2026 20:29:43 +0100
Subject: [PATCH] jinja : fix undefined keys and attributes and int/float as
 bool (#18924)

* fix undefined keys and attributes

* add falsy tests

* as_bool for integers and floats

* more falsy/truthy tests

* --typo
---
 common/jinja/runtime.cpp |  4 +--
 common/jinja/value.h     |  6 ++++
 tests/test-jinja.cpp     | 78 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+), 2 deletions(-)

diff --git a/common/jinja/runtime.cpp b/common/jinja/runtime.cpp
index d8ef279080..e3e4ebf1ec 100644
--- a/common/jinja/runtime.cpp
+++ b/common/jinja/runtime.cpp
@@ -805,7 +805,7 @@ value member_expression::execute_impl(context & ctx) {
         } else if (is_val<value_string>(property)) {
             auto key = property->as_string().str();
             JJ_DEBUG("Accessing %s built-in '%s'", is_val<value_array>(object) ? "array" : "string", key.c_str());
-            val = try_builtin_func(ctx, key, object);
+            val = try_builtin_func(ctx, key, object, true);
         } else {
             throw std::runtime_error("Cannot access property with non-string/non-number: got " + property->type());
         }
@@ -814,7 +814,7 @@ value member_expression::execute_impl(context & ctx) {
             throw std::runtime_error("Cannot access property with non-string: got " + property->type());
         }
         auto key = property->as_string().str();
-        val = try_builtin_func(ctx, key, object);
+        val = try_builtin_func(ctx, key, object, true);
     }
 
     if (ctx.is_get_stats && val && object && property) {
diff --git a/common/jinja/value.h b/common/jinja/value.h
index 4e916919b3..7bd0202cea 100644
--- a/common/jinja/value.h
+++ b/common/jinja/value.h
@@ -203,6 +203,9 @@ struct value_int_t : public value_t {
     virtual int64_t as_int() const override { return val_int; }
     virtual double as_float() const override { return static_cast<double>(val_int); }
     virtual string as_string() const override { return std::to_string(val_int); }
+    virtual bool as_bool() const override {
+        return val_int != 0;
+    }
     virtual const func_builtins & get_builtins() const override;
 };
 using value_int = std::shared_ptr<value_int_t>;
@@ -219,6 +222,9 @@ struct value_float_t : public value_t {
         if (out.back() == '.') out.push_back('0'); // leave one zero if no decimals
         return out;
     }
+    virtual bool as_bool() const override {
+        return val_flt != 0.0;
+    }
     virtual const func_builtins & get_builtins() const override;
 };
 using value_float = std::shared_ptr<value_float_t>;
diff --git a/tests/test-jinja.cpp b/tests/test-jinja.cpp
index 13818381ed..99630ecb3b 100644
--- a/tests/test-jinja.cpp
+++ b/tests/test-jinja.cpp
@@ -191,6 +191,84 @@ static void test_conditionals(testing & t) {
         json::object(),
         "yes"
     );
+
+    test_template(t, "is undefined falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is undefined attribute falsy",
+        "{{ 'yes' if not y.x else 'no' }}",
+        {{"y", true}},
+        "yes"
+    );
+
+    test_template(t, "is undefined key falsy",
+        "{{ 'yes' if not y['x'] else 'no' }}",
+        {{"y", {{}}}},
+        "yes"
+    );
+
+    test_template(t, "is empty array falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", json::array()}},
+        "yes"
+    );
+
+    test_template(t, "is empty object falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", json::object()}},
+        "yes"
+    );
+
+    test_template(t, "is empty string falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", ""}},
+        "yes"
+    );
+
+    test_template(t, "is 0 falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", 0}},
+        "yes"
+    );
+
+    test_template(t, "is 0.0 falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", 0.0}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty array truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", json::array({""})}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty object truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", {"x", false}}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty string truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", "0"}},
+        "yes"
+    );
+
+    test_template(t, "is 1 truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", 1}},
+        "yes"
+    );
+
+    test_template(t, "is 1.0 truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", 1.0}},
+        "yes"
+    );
 }
 
 static void test_loops(testing & t) {