Backout changeset 46393019b650

test_capi is failing and the fix is not trivial, I prefer to revert

3 files changed, 24 insertions, 8 deletions

diff --git a/Python/thread.c b/Python/thread.c
index 5396ca3..8540942 100644
--- a/Python/thread.c
+++ b/Python/thread.c
@@ -205,7 +205,7 @@ static int nkeys = 0;  /* PyThread_create_key() hands out nkeys+1 next */
  * segfaults.  Now we lock the whole routine.
  */
 static struct key *
-find_key(int key, int update, void *value)
+find_key(int key, void *value)
 {
     struct key *p, *prev_p;
     long id = PyThread_get_thread_ident();
@@ -215,11 +215,8 @@ find_key(int key, int update, void *value)
     PyThread_acquire_lock(keymutex, 1);
     prev_p = NULL;
     for (p = keyhead; p != NULL; p = p->next) {
-        if (p->id == id && p->key == key) {
-            if (update)
-                p->value = value;
+        if (p->id == id && p->key == key)
             goto Done;
-        }
         /* Sanity check.  These states should never happen but if
          * they do we must abort.  Otherwise we'll end up spinning in
          * in a tight loop with the lock held.  A similar check is done
@@ -230,7 +227,7 @@ find_key(int key, int update, void *value)
         if (p->next == keyhead)
             Py_FatalError("tls find_key: circular list(!)");
     }
-    if (!update && value == NULL) {
+    if (value == NULL) {
         assert(p == NULL);
         goto Done;
     }
@@ -282,12 +279,19 @@ PyThread_delete_key(int key)
     PyThread_release_lock(keymutex);
 }
 
+/* Confusing:  If the current thread has an association for key,
+ * value is ignored, and 0 is returned.  Else an attempt is made to create
+ * an association of key to value for the current thread.  0 is returned
+ * if that succeeds, but -1 is returned if there's not enough memory
+ * to create the association.  value must not be NULL.
+ */
 int
 PyThread_set_key_value(int key, void *value)
 {
     struct key *p;
 
-    p = find_key(key, 1, value);
+    assert(value != NULL);
+    p = find_key(key, value);
     if (p == NULL)
         return -1;
     else
@@ -300,7 +304,7 @@ PyThread_set_key_value(int key, void *value)
 void *
 PyThread_get_key_value(int key)
 {
-    struct key *p = find_key(key, 0, NULL);
+    struct key *p = find_key(key, NULL);
 
     if (p == NULL)
         return NULL;
diff --git a/Python/thread_nt.h b/Python/thread_nt.h
index ee2079f..ab5a081 100644
--- a/Python/thread_nt.h
+++ b/Python/thread_nt.h
@@ -389,11 +389,20 @@ PyThread_delete_key(int key)
     TlsFree(key);
 }
 
+/* We must be careful to emulate the strange semantics implemented in thread.c,
+ * where the value is only set if it hasn't been set before.
+ */
 int
 PyThread_set_key_value(int key, void *value)
 {
     BOOL ok;
+    void *oldvalue;
 
+    assert(value != NULL);
+    oldvalue = TlsGetValue(key);
+    if (oldvalue != NULL)
+        /* ignore value if already set */
+        return 0;
     ok = TlsSetValue(key, value);
     if (!ok)
         return -1;
diff --git a/Python/thread_pthread.h b/Python/thread_pthread.h
index d9f7c76..20f8535 100644
--- a/Python/thread_pthread.h
+++ b/Python/thread_pthread.h
@@ -627,6 +627,9 @@ int
 PyThread_set_key_value(int key, void *value)
 {
     int fail;
+    void *oldValue = pthread_getspecific(key);
+    if (oldValue != NULL)
+        return 0;
     fail = pthread_setspecific(key, value);
     return fail ? -1 : 0;
 }