Fix issue causing scanners to receive incorrect paths

CHANGES.txt

@@ -25,6 +25,14 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - Added --experimental flag, to enable various experimental features/tools.  You can specify
       'all', 'none', or any combination of available experimental features.
 
+  From Adam Gross:
+    - Fix an issue causing scanners to receive incorrect paths when the
+      environment contains a Directory node that is a subdirectory of the
+      source root directory, the environment variable used by the scanner
+      (e.g. env['LIBPATH']) references a subdirectory of that directory node,
+      and a SConscript file is being run that is not in the source root
+      directory.
+
   From David H:
     - Fix Issue #3906 - `IMPLICIT_COMMAND_DEPENDENCIES` was not properly disabled when
       set to any string value (For example ['none','false','no','off'])
@@ -145,7 +153,6 @@ RELEASE 4.1.0 - Tues, 19 Jan 2021 15:04:42 -0700
     - Fix python3 crash when Value node get_text_content when child content does not have decode()
       NOTE: If you depend on Value node's get_text_content returning concatenated contents of it's
       children. This may break your code. It now concatenates the csig() of all children.
->>>>>>> master
 
   From Joachim Kuebart:
     - Suppress missing SConscript deprecation warning if `must_exist=False`

SCons/PathList.py

@@ -20,6 +20,7 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
 
 """Handle lists of directory paths.
 
@@ -43,6 +44,7 @@
 TYPE_STRING_SUBST = 1           # string containing '$'
 TYPE_OBJECT = 2                 # other object
 
+
 def node_conv(obj):
     """
     This is the "string conversion" routine that we have our substitutions
@@ -63,6 +65,7 @@ def node_conv(obj):
         result = get()
     return result
 
+
 class _PathList:
     """
     An actual PathList object.
@@ -123,15 +126,20 @@ def subst_path(self, env, target, source):
         PathList for a specific target and source.
         """
         result = []
-        for type, value in self.pathlist:
-            if type == TYPE_STRING_SUBST:
-                value = env.subst(value, target=target, source=source,
-                                  conv=node_conv)
+        for pathlist_type, value in self.pathlist:
+            if pathlist_type == TYPE_STRING_SUBST:
+                # We override conv below to use absolute paths when possible.
+                # This avoids problems with relative paths when the target's
+                # working directory is different than the FS object's working
+                # directory.
+                value = env.subst(
+                    value, target=target, source=source,
+                    conv=lambda x: x.abspath if hasattr(x, 'abspath') else x)
                 if SCons.Util.is_Sequence(value):
                     result.extend(SCons.Util.flatten(value))
                 elif value:
                     result.append(value)
-            elif type == TYPE_OBJECT:
+            elif pathlist_type == TYPE_OBJECT:
                 value = node_conv(value)
                 if value:
                     result.append(value)

test/ScannerAbsPathCheck/fixture/SConstruct

@@ -0,0 +1,43 @@
+import os
+import sys
+import SCons.Scanner
+
+sdk_root = None
+
+def verify_paths(node, env, scanpaths, arg):
+    """Verifies that the paths provided are as expected."""
+    global sdk_root
+    sdk_root_subdir = os.path.join(sdk_root, 'sdk_subdir')
+    if len(scanpaths) != 2:
+        raise Exception('Expected two entries in scanpaths')
+    if scanpaths[0].abspath != sdk_root:
+        raise Exception('Expected first scanpath=%s, got %s.' %
+                        (sdk_root, scanpaths[0].abspath))
+    if scanpaths[1].abspath != sdk_root_subdir:
+        raise Exception('Expected second scanpath=%s, got %s.' %
+                        (sdk_root_subdir, scanpaths[1].abspath))
+    return []
+
+
+# Create a scanner that generates a path using the variables in env['PYPATH'].
+pyscan = Scanner(name='pythonfile',
+                 function=verify_paths,
+                 argument=None,
+                 path_function=SCons.Scanner.FindPathDirs('PYPATH'),
+                 skeys=['.py'])
+
+# Create a builder that uses that scanner.
+b = Builder(action='$PYTHON $SOURCE', source_scanner=pyscan)
+
+env = Environment(BUILDERS={'DummyPythonBuilder': b})
+
+# Now set some variables that are needed by the scanner and/or the SConscript.
+env.Replace(
+    PYTHON=sys.executable,
+    PYPATH=['$SDKROOT', '$SDKROOT/sdk_subdir'],
+    SDKROOT=env.Dir('sdk'),
+)
+sdk_root = env['SDKROOT'].abspath
+
+Export('env')
+SConscript('subdir/SConscript', exports='env')

test/ScannerAbsPathCheck/fixture/subdir/SConscript

@@ -0,0 +1,2 @@
+Import('env')
+env.DummyPythonBuilder(target=['foo'], source=['empty.py'])

test/ScannerAbsPathCheck/test.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+"""
+This test verifies that a scanner retrieves the correct paths when
+path_function is set to SCons.Scanner.FindPathDirs(some_var) and env[some_var]
+contains paths relative to the SConstruct root.
+"""
+
+import TestSCons
+
+test = TestSCons.TestSCons()
+
+test.dir_fixture('fixture')
+test.run()
+
+test.pass_test()
+
+# Local Variables:
+# tab-width:4
+# indent-tabs-mode:nil
+# End:
+# vim: set expandtab tabstop=4 shiftwidth=4: