Respect thread local fluid defaults

Previously (fluid-ref (make-thread-local-fluid #t)) would return #f via
scm_fluid_ref because the internal scm_hashq_ref would return #f when
the fluid had not been set, and that was interpreted as an actual value
for the fluid.

Instead, just pass the fluid default as the default for the hash table
lookups so that we don't need a second step to determine if the fluid
was set.

Thanks to Andrew Gierth for tracking down the problem.

2 files changed, 21 insertions, 16 deletions

diff --git a/libguile/fluids.c b/libguile/fluids.c
index c3dd1c9ea..472f92a06 100644
--- a/libguile/fluids.c
+++ b/libguile/fluids.c
@@ -343,22 +343,17 @@ fluid_ref (scm_t_dynamic_state *dynamic_state, SCM fluid)
 
   entry = scm_cache_lookup (&dynamic_state->cache, fluid);
   if (scm_is_eq (SCM_PACK (entry->key), fluid))
-    val = SCM_PACK (entry->value);
-  else
-    {
-      if (SCM_I_FLUID_THREAD_LOCAL_P (fluid))
-        val = scm_hashq_ref (dynamic_state->thread_local_values, fluid,
-                             SCM_UNDEFINED);
-      else
-        val = scm_weak_table_refq (dynamic_state->values, fluid,
-                                   SCM_UNDEFINED);
+    return SCM_PACK (entry->value);
 
-      if (SCM_UNBNDP (val))
-        val = SCM_I_FLUID_DEFAULT (fluid);
+  if (SCM_I_FLUID_THREAD_LOCAL_P (fluid))
+    val = scm_hashq_ref (dynamic_state->thread_local_values, fluid,
+                         SCM_I_FLUID_DEFAULT (fluid));
+  else
+    val = scm_weak_table_refq (dynamic_state->values, fluid,
+                         SCM_I_FLUID_DEFAULT (fluid));
 
-      /* Cache this lookup.  */
-      fluid_set_x (dynamic_state, fluid, val);
-    }
+  /* Cache this lookup.  */
+  fluid_set_x (dynamic_state, fluid, val);
 
   return val;
 }
diff --git a/test-suite/tests/fluids.test b/test-suite/tests/fluids.test
index a5ca8857e..949d50410 100644
--- a/test-suite/tests/fluids.test
+++ b/test-suite/tests/fluids.test
@@ -49,8 +49,18 @@
 	  (interaction-environment))))
 
 (with-test-prefix "initial fluid values"
-  (pass-if "fluid-ref uninitialized fluid is #f"
-    (not (fluid-ref a)))
+
+  (pass-if "fluid-ref returns #f for uninitialized fluid"
+    (eq? #f (fluid-ref (make-fluid))))
+
+  (pass-if "fluid-ref returns #f for uninitialized thread local fluid"
+    (eq? #f (fluid-ref (make-thread-local-fluid))))
+
+  (pass-if "fluid-ref returns default"
+    (eq? #t (fluid-ref (make-fluid #t))))
+
+  (pass-if "fluid-ref returns thread local default"
+    (eq? #t (fluid-ref (make-thread-local-fluid #t))))
 
   (pass-if "initial value is inherited from parent thread"
     (if (provided? 'threads)