libexpr/parser: Test experimental features

Currently, the parser relies on the global experimental feature flags.
In order to properly test conditional language features, we instead need
to pass it around in the parser::State.

This means that the parser cannot cache the result of isEnabled anymore,
which wouldn't necessarily hurt performance if the function didn't
perform a linear search on the list of enabled features on every single
call. While we could simply evaluate once at the start of parsing and
cache the result in the parser state, the more sustainable solution
would be to fix `isEnabled` such that all callers may profit from the
performance improvement.

Change-Id: Ic9b9c5d882b6270e1114988b63e6064d36c25cf2

2 files changed, 19 insertions, 2 deletions

diff --git a/tests/unit/libexpr-support/tests/libexpr.hh b/tests/unit/libexpr-support/tests/libexpr.hh
index 01dcbb34c..745aa168d 100644
--- a/tests/unit/libexpr-support/tests/libexpr.hh
+++ b/tests/unit/libexpr-support/tests/libexpr.hh
@@ -26,9 +26,9 @@ namespace nix {
                 , state({}, store)
             {
             }
-            Value eval(std::string input, bool forceValue = true) {
+            Value eval(std::string input, bool forceValue = true, const ExperimentalFeatureSettings & xpSettings = experimentalFeatureSettings) {
                 Value v;
-                Expr & e = state.parseExprFromString(input, state.rootPath(CanonPath::root));
+                Expr & e = state.parseExprFromString(input, state.rootPath(CanonPath::root), xpSettings);
                 state.eval(e, v);
                 if (forceValue)
                     state.forceValue(v, noPos);
diff --git a/tests/unit/libexpr/trivial.cc b/tests/unit/libexpr/trivial.cc
index 171727ac7..19b62aff8 100644
--- a/tests/unit/libexpr/trivial.cc
+++ b/tests/unit/libexpr/trivial.cc
@@ -59,6 +59,11 @@ namespace nix {
         ASSERT_THAT(v, IsFloatEq(1.234));
     }
 
+    TEST_F(TrivialExpressionTest, pointfloat) {
+        auto v = eval(".234");
+        ASSERT_THAT(v, IsFloatEq(0.234));
+    }
+
     TEST_F(TrivialExpressionTest, updateAttrs) {
         auto v = eval("{ a = 1; } // { b = 2; a = 3; }");
         ASSERT_THAT(v, IsAttrsOfSize(2));
@@ -81,6 +86,18 @@ namespace nix {
         ASSERT_THAT(v, IsTrue());
     }
 
+    TEST_F(TrivialExpressionTest, urlLiteral) {
+        auto v = eval("https://nixos.org");
+        ASSERT_THAT(v, IsStringEq("https://nixos.org"));
+    }
+
+    TEST_F(TrivialExpressionTest, noUrlLiteral) {
+        ExperimentalFeatureSettings mockXpSettings;
+        mockXpSettings.set("experimental-features", "no-url-literals");
+
+        ASSERT_THROW(eval("https://nixos.org", true, mockXpSettings), Error);
+    }
+
     TEST_F(TrivialExpressionTest, withFound) {
         auto v = eval("with { a = 23; }; a");
         ASSERT_THAT(v, IsIntEq(23));