Merge pull request SCons#4505 from mwichmann/py313-isabs

Fix isabs() check in NodeInfo for Py 3.13

Author: bdbaddog

CHANGES.txt

@@ -17,6 +17,8 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - Dump() with json format selected now recognizes additional compound types
       (UserDict and UserList), which improves the detail of the display.
       json output is also sorted, to match the default display.
+    - Python 3.13 (alpha) changes the behavior of isabs() on Windows. Adjust
+      SCons usage of in NodeInfo classes to match.  Fixes #4502, #4504.
 
 
 RELEASE 4.7.0 -  Sun, 17 Mar 2024 17:22:20 -0700

RELEASE.txt

@@ -29,6 +29,8 @@ CHANGED/ENHANCED EXISTING FUNCTIONALITY
 - Dump() with json format selected now recognizes additional compound types
   (UserDict and UserList), which improves the detail of the display.
   json output is also sorted, to match the default display.
+- Python 3.13 changes the behavior of isabs() on Windows. Adjust SCons
+  usage of this in NodeInfo classes to avoid test problems.
 
 FIXES
 -----

SCons/Node/FS.py

@@ -120,43 +120,41 @@ def save_strings(val) -> None:
     global Save_Strings
     Save_Strings = val
 
-#
-# Avoid unnecessary function calls by recording a Boolean value that
-# tells us whether or not os.path.splitdrive() actually does anything
-# on this system, and therefore whether we need to bother calling it
-# when looking up path names in various methods below.
-#
 
 do_splitdrive = None
-_my_splitdrive =None
+_my_splitdrive = None
 
 def initialize_do_splitdrive() -> None:
-    global do_splitdrive
-    global has_unc
-    drive, path = os.path.splitdrive('X:/foo')
-    # splitunc is removed from python 3.7 and newer
-    # so we can also just test if splitdrive works with UNC
-    has_unc = (hasattr(os.path, 'splitunc')
-        or os.path.splitdrive(r'\\split\drive\test')[0] == r'\\split\drive')
-
-    do_splitdrive = not not drive or has_unc
-
-    global _my_splitdrive
-    if has_unc:
-        def splitdrive(p):
+    """Set up splitdrive usage.
+
+    Avoid unnecessary function calls by recording a flag that tells us whether
+    or not :func:`os.path.splitdrive` actually does anything on this system,
+    and therefore whether we need to bother calling it when looking up path
+    names in various methods below.
+
+    If :data:`do_splitdrive` is True, :func:`_my_splitdrive` will be a real
+    function which we can call. As all supported Python versions' ntpath module
+    now handle UNC paths correctly, we no longer special-case that.
+
+    Deferring the setup of ``_my_splitdrive`` also lets unit tests do
+    their thing and test UNC path handling on a POSIX host.
+    """
+    global do_splitdrive, _my_splitdrive
+
+    do_splitdrive = bool(os.path.splitdrive('X:/foo')[0])
+
+    if do_splitdrive:
+        def _my_splitdrive(p):
             if p[1:2] == ':':
                 return p[:2], p[2:]
             if p[0:2] == '//':
                 # Note that we leave a leading slash in the path
                 # because UNC paths are always absolute.
                 return '//', p[1:]
             return '', p
-    else:
-        def splitdrive(p):
-            if p[1:2] == ':':
-                return p[:2], p[2:]
-            return '', p
-    _my_splitdrive = splitdrive
+    # TODO: the os routine should work and be better debugged than ours,
+    #   but unit test test_unc_path fails on POSIX platforms. Resolve someday.
+    # _my_splitdrive = os.path.splitdrive
 
     # Keep some commonly used values in global variables to skip to
     # module look-up costs.
@@ -1238,7 +1236,10 @@ def __init__(self, path = None) -> None:
             self.pathTop = os.getcwd()
         else:
             self.pathTop = path
-        self.defaultDrive = _my_normcase(_my_splitdrive(self.pathTop)[0])
+        if do_splitdrive:
+            self.defaultDrive = _my_normcase(_my_splitdrive(self.pathTop)[0])
+        else:
+            self.defaultDrive = ""
 
         self.Top = self.Dir(self.pathTop)
         self.Top._path = '.'
@@ -1554,11 +1555,15 @@ class DirNodeInfo(SCons.Node.NodeInfoBase):
     def str_to_node(self, s):
         top = self.fs.Top
         root = top.root
+        # Python 3.13/Win changed isabs() - after you split C:/foo/bar,
+        # the path part is no longer considerd absolute. Save the passed
+        # path for the isabs check so we can get the right answer.
+        path = s
         if do_splitdrive:
             drive, s = _my_splitdrive(s)
             if drive:
                 root = self.fs.get_root(drive)
-        if not os.path.isabs(s):
+        if not os.path.isabs(path):
             s = top.get_labspath() + '/' + s
         return root._lookup_abs(s, Entry)
 
@@ -2380,7 +2385,7 @@ def __init__(self, drive, fs) -> None:
         # The // entry is necessary because os.path.normpath()
         # preserves double slashes at the beginning of a path on Posix
         # platforms.
-        if not has_unc:
+        if not do_splitdrive:
             self._lookupDict['//'] = self
 
     def _morph(self) -> None:
@@ -2511,11 +2516,15 @@ class FileNodeInfo(SCons.Node.NodeInfoBase):
     def str_to_node(self, s):
         top = self.fs.Top
         root = top.root
+        # Python 3.13/Win changed isabs() - after you split C:/foo/bar,
+        # the path part is no longer considerd absolute. Save the passed
+        # path for the isabs check so we can get the right answer.
+        path = s
         if do_splitdrive:
             drive, s = _my_splitdrive(s)
             if drive:
                 root = self.fs.get_root(drive)
-        if not os.path.isabs(s):
+        if not os.path.isabs(path):
             s = top.get_labspath() + '/' + s
         return root._lookup_abs(s, Entry)
 
@@ -3534,7 +3543,7 @@ def is_up_to_date(self) -> bool:
 
         In all cases self is the target we're checking to see if it's up to date
         """
-        T = 0
+        T = False
         if T: Trace('is_up_to_date(%s):' % self)
         if not self.exists():
             if T: Trace(' not self.exists():')
@@ -3730,7 +3739,10 @@ def filedir_lookup(self, p, fd=None):
         if fd is None:
             fd = self.default_filedir
         dir, name = os.path.split(fd)
-        drive, d = _my_splitdrive(dir)
+        if do_splitdrive:
+            drive, d = _my_splitdrive(dir)
+        else:
+            drive, d = "", dir
         if not name and d[:1] in ('/', OS_SEP):
             #return p.fs.get_root(drive).dir_on_disk(name)
             return p.fs.get_root(drive)

SCons/Node/__init__.py

@@ -1063,6 +1063,7 @@ def scan(self) -> None:
         # Don't bother scanning non-derived files, because we don't
         # care what their dependencies are.
         # Don't scan again, if we already have scanned.
+        T = False
         if self.implicit is not None:
             return
         self.implicit = []
@@ -1087,7 +1088,12 @@ def scan(self) -> None:
                 # essentially short-circuits an N*M scan of the
                 # sources for each individual target, which is a hell
                 # of a lot more efficient.
+                def print_nodelist(n):
+                    tgts = [f"{t.path!r}" for t in n]
+                    return f"[{', '.join(tgts)}]"
+
                 for tgt in executor.get_all_targets():
+                    if T: Trace(f"adding implicit {print_nodelist(implicit)} to {tgt!s}\n")
                     tgt.add_to_implicit(implicit)
 
                 if implicit_deps_unchanged or self.is_up_to_date():
@@ -1472,8 +1478,8 @@ def changed(self, node=None, allowcache: bool=False):
 
         @see: FS.File.changed(), FS.File.release_target_info()
         """
-        t = 0
-        if t: Trace('changed(%s [%s], %s)' % (self, classname(self), node))
+        T = False
+        if T: Trace('changed(%s [%s], %s)' % (self, classname(self), node))
         if node is None:
             node = self
 
@@ -1491,25 +1497,24 @@ def changed(self, node=None, allowcache: bool=False):
             # entries to equal the new dependency list, for the benefit
             # of the loop below that updates node information.
             then.extend([None] * diff)
-            if t: Trace(': old %s new %s' % (len(then), len(children)))
+            if T: Trace(': old %s new %s' % (len(then), len(children)))
             result = True
 
         for child, prev_ni in zip(children, then):
             if _decider_map[child.changed_since_last_build](child, self, prev_ni, node):
-                if t: Trace(': %s changed' % child)
+                if T: Trace(f": '{child!s}' changed")
                 result = True
 
         if self.has_builder():
             contents = self.get_executor().get_contents()
             newsig = hash_signature(contents)
             if bi.bactsig != newsig:
-                if t: Trace(': bactsig %s != newsig %s' % (bi.bactsig, newsig))
+                if T: Trace(': bactsig %s != newsig %s' % (bi.bactsig, newsig))
                 result = True
 
         if not result:
-            if t: Trace(': up to date')
-
-        if t: Trace('\n')
+            if T: Trace(': up to date')
+        if T: Trace('\n')
 
         return result