fix Issue 15353 - ignore freeing during finalization

Author: MartinNowak

changelog.dd

@@ -7,6 +7,7 @@ $(BUGSTITLE Library Changes,
 
 $(LI $(RELATIVE_LINK2 aa-clear, A `clear` method has been added to associative
     arrays to remove all elements.))
+$(LI Calls to $(NCXREF memory, GC.free) are now ignored during finalization instead of throwing an InvalidMemoryOperationError, see $(BUGZILLA 15353).)
 )
 
 $(BUGSTITLE Library Changes,
@@ -42,6 +43,12 @@ Macros:
     COREMODREF = <a href="phobos/core_$1.html">$2</a>
     XREF = <a href="phobos/std_$1.html#$2">$2</a>
     CXREF = <a href="phobos/core_$1.html#$2">$2</a>
+    OXREF = <a href="phobos/object.html#$2">$2</a>
+    NXREF = <a href="phobos/std_$1.html#.$2">$2</a>
+    NCXREF = <a href="phobos/core_$1.html#.$2">$2</a>
+    NOXREF = <a href="phobos/object.html#.$2">$2</a>
+
+    BUGZILLA = <a href="https://issues.dlang.org/show_bug.cgi?id=$0">Bugzilla $0</a>
 
     BOOKTABLE = <table><caption>$1</caption>$+</table>
     PRE = <pre>$0</pre>

src/core/memory.d

@@ -552,12 +552,12 @@ struct GC
 
 
     /**
-     * Deallocates the memory referenced by p.  If p is null, no action
-     * occurs.  If p references memory not originally allocated by this
-     * garbage collector, or if it points to the interior of a memory block,
-     * no action will be taken.  The block will not be finalized regardless
-     * of whether the FINALIZE attribute is set.  If finalization is desired,
-     * use delete instead.
+     * Deallocates the memory referenced by p.  If p is null, no action occurs.
+     * If p references memory not originally allocated by this garbage
+     * collector, if p points to the interior of a memory block, or if this
+     * method is called from a finalizer, no action will be taken.  The block
+     * will not be finalized regardless of whether the FINALIZE attribute is
+     * set.  If finalization is desired, use delete instead.
      *
      * Params:
      *  p = A pointer to the root of a valid memory block or to null.

src/gc/gc.d

@@ -813,7 +813,7 @@ struct GC
      */
     void free(void *p) nothrow
     {
-        if (!p)
+        if (!p || inFinalizer)
         {
             return;
         }
@@ -3250,6 +3250,23 @@ unittest // bugzilla 14467
     assert(arr.capacity);
 }
 
+unittest // bugzilla 15353
+{
+    import core.memory : GC;
+
+    static struct Foo
+    {
+        ~this()
+        {
+            GC.free(buf); // ignored in finalizer
+        }
+
+        void* buf;
+    }
+    new Foo(GC.malloc(10));
+    GC.collect();
+}
+
 /* ============================ SENTINEL =============================== */