Improve readability of LIB substitution code

2 files changed, 17 insertions, 16 deletions

diff --git a/src/engine/SCons/Scanner/Prog.py b/src/engine/SCons/Scanner/Prog.py
index 848f874..4781175 100644
--- a/src/engine/SCons/Scanner/Prog.py
+++ b/src/engine/SCons/Scanner/Prog.py
@@ -38,13 +38,21 @@ def ProgramScanner(**kw):
     ps = SCons.Scanner.Base(scan, "ProgramScanner", **kw)
     return ps
 
-def _split_libs(env, libs):
+def _subst_libs(env, libs):
     """
     Substitute environment variables and split into list.
     """
-    libs = env.subst(libs)
     if SCons.Util.is_String(libs):
-        libs = libs.split()
+        libs = env.subst(libs)
+        if SCons.Util.is_String(libs):
+            libs = libs.split()
+    elif SCons.Util.is_Sequence(libs):
+        _libs = []
+        for l in libs:
+            _libs += _subst_libs(env, l)
+        libs = _libs
+    else:
+        libs = [libs]
     return libs
 
 def scan(node, env, libpath = ()):
@@ -59,12 +67,8 @@ def scan(node, env, libpath = ()):
     except KeyError:
         # There are no LIBS in this environment, so just return a null list:
         return []
-    if SCons.Util.is_String(libs):
-        libs = _split_libs(env, libs)
-    else:
-        libs = SCons.Util.flatten(libs)
-        libs = map(lambda x: _split_libs(env, x) if SCons.Util.is_String(x) else x, libs)
-    libs = SCons.Util.flatten(libs)
+
+    libs = _subst_libs(env, libs)
 
     try:
         prefix = env['LIBPREFIXES']
diff --git a/src/engine/SCons/Scanner/ProgTests.py b/src/engine/SCons/Scanner/ProgTests.py
index 98e20cc..ace3ff4 100644
--- a/src/engine/SCons/Scanner/ProgTests.py
+++ b/src/engine/SCons/Scanner/ProgTests.py
@@ -32,6 +32,7 @@ import TestUnit
 
 import SCons.Node.FS
 import SCons.Scanner.Prog
+import SCons.Subst
 
 test = TestCmd.TestCmd(workdir = '')
 
@@ -72,12 +73,7 @@ class DummyEnvironment(object):
         del self.Dictionary()[key]
 
     def subst(self, s, target=None, source=None, conv=None):
-        try:
-            if isinstance(s, str) and s[0] == '$':
-                return self._dict[s[1:]]
-        except IndexError:
-            return ''
-        return s
+        return SCons.Subst.scons_subst(s, self, gvars=self._dict, lvars=self._dict)
 
     def subst_path(self, path, target=None, source=None, conv=None):
         if not isinstance(path, list):
@@ -241,7 +237,8 @@ class ProgramScannerTestCase10(unittest.TestCase):
                                LIBS=['foo', '$LIBBAR'],
                                LIBPREFIXES=['lib'],
                                LIBSUFFIXES=['.a'],
-                               LIBBAR='sub/libbar xyz.other')
+                               LIBBAR='sub/libbar $LIBBAR2',
+                               LIBBAR2=['xyz.other'])
         s = SCons.Scanner.Prog.ProgramScanner()
         path = s.path(env)
         deps = s(DummyNode('dummy'), env, path)