bpo-45506: Normalize _PyPathConfig.stdlib_dir when calculated. (#29040)

The recently added PyConfig.stdlib_dir was being set with ".." entries. When __file__ was added for from modules this caused a problem on out-of-tree builds. This PR fixes that by normalizing "stdlib_dir" when it is calculated in getpath.c.

https://bugs.python.org/issue45506

1 files changed, 40 insertions, 6 deletions

diff --git a/Modules/getpath.c b/Modules/getpath.c
index 1405023..4dbd502 100644
--- a/Modules/getpath.c
+++ b/Modules/getpath.c
@@ -520,6 +520,42 @@ search_for_prefix(PyCalculatePath *calculate, _PyPathConfig *pathconfig,
 
 
 static PyStatus
+calculate_set_stdlib_dir(PyCalculatePath *calculate, _PyPathConfig *pathconfig)
+{
+    // Note that, unlike calculate_set_prefix(), here we allow a negative
+    // prefix_found.  That means the source tree Lib dir gets used.
+    if (!calculate->prefix_found) {
+        return _PyStatus_OK();
+    }
+    PyStatus status;
+    wchar_t *prefix = calculate->prefix;
+    if (!_Py_isabs(prefix)) {
+        prefix = _PyMem_RawWcsdup(prefix);
+        if (prefix == NULL) {
+            return _PyStatus_NO_MEMORY();
+        }
+        status = absolutize(&prefix);
+        if (_PyStatus_EXCEPTION(status)) {
+            return status;
+        }
+    }
+    wchar_t buf[MAXPATHLEN + 1];
+    int res = _Py_normalize_path(prefix, buf, Py_ARRAY_LENGTH(buf));
+    if (prefix != calculate->prefix) {
+        PyMem_RawFree(prefix);
+    }
+    if (res < 0) {
+        return PATHLEN_ERR();
+    }
+    pathconfig->stdlib_dir = _PyMem_RawWcsdup(buf);
+    if (pathconfig->stdlib_dir == NULL) {
+        return _PyStatus_NO_MEMORY();
+    }
+    return _PyStatus_OK();
+}
+
+
+static PyStatus
 calculate_prefix(PyCalculatePath *calculate, _PyPathConfig *pathconfig)
 {
     wchar_t prefix[MAXPATHLEN+1];
@@ -1494,12 +1530,10 @@ calculate_path(PyCalculatePath *calculate, _PyPathConfig *pathconfig)
     }
 
     if (pathconfig->stdlib_dir == NULL) {
-        if (calculate->prefix_found) {
-            /* This must be done *before* calculate_set_prefix() is called. */
-            pathconfig->stdlib_dir = _PyMem_RawWcsdup(calculate->prefix);
-            if (pathconfig->stdlib_dir == NULL) {
-                return _PyStatus_NO_MEMORY();
-            }
+        /* This must be done *before* calculate_set_prefix() is called. */
+        status = calculate_set_stdlib_dir(calculate, pathconfig);
+        if (_PyStatus_EXCEPTION(status)) {
+            return status;
         }
     }