Solution for Issue SCons#4275 (Compilation db get's tmp file command …

…line), also extending serveral APIs to allow specifying an overrides dictionary which would override (at the last minute) any envvar or potentially env TARGET/SOURCE when subst is being called a subst() or subst_list(). Tests created. Docs still need to be updated.

SCons/Action.py

@@ -875,11 +875,11 @@ def __str__(self):
             return ' '.join(map(str, self.cmd_list))
         return str(self.cmd_list)
 
-    def process(self, target, source, env, executor=None):
+    def process(self, target, source, env, executor=None, overrides=False):
         if executor:
-            result = env.subst_list(self.cmd_list, 0, executor=executor)
+            result = env.subst_list(self.cmd_list, 0, executor=executor, overrides=overrides)
         else:
-            result = env.subst_list(self.cmd_list, 0, target, source)
+            result = env.subst_list(self.cmd_list, 0, target, source, overrides=overrides)
         silent = None
         ignore = None
         while True:
@@ -896,18 +896,18 @@ def process(self, target, source, env, executor=None):
             pass
         return result, ignore, silent
 
-    def strfunction(self, target, source, env, executor=None):
+    def strfunction(self, target, source, env, executor=None, overrides=False):
         if self.cmdstr is None:
             return None
         if self.cmdstr is not _null:
             from SCons.Subst import SUBST_RAW
             if executor:
-                c = env.subst(self.cmdstr, SUBST_RAW, executor=executor)
+                c = env.subst(self.cmdstr, SUBST_RAW, executor=executor, overrides=overrides)
             else:
-                c = env.subst(self.cmdstr, SUBST_RAW, target, source)
+                c = env.subst(self.cmdstr, SUBST_RAW, target, source, overrides=overrides)
             if c:
                 return c
-        cmd_list, ignore, silent = self.process(target, source, env, executor)
+        cmd_list, ignore, silent = self.process(target, source, env, executor, overrides=overrides)
         if silent:
             return ''
         return _string_from_cmd_list(cmd_list[0])

SCons/ActionTests.py

@@ -142,15 +142,15 @@ def __init__(self, **kw):
             self.d[k] = v
 
     # Just use the underlying scons_subst*() utility methods.
-    def subst(self, strSubst, raw=0, target=[], source=[], conv=None):
+    def subst(self, strSubst, raw=0, target=[], source=[], conv=None, overrides=False):
         return SCons.Subst.scons_subst(strSubst, self, raw,
-                                       target, source, self.d, conv=conv)
+                                       target, source, self.d, conv=conv, overrides=overrides)
 
     subst_target_source = subst
 
-    def subst_list(self, strSubst, raw=0, target=[], source=[], conv=None):
+    def subst_list(self, strSubst, raw=0, target=[], source=[], conv=None, overrides=False):
         return SCons.Subst.scons_subst_list(strSubst, self, raw,
-                                            target, source, self.d, conv=conv)
+                                            target, source, self.d, conv=conv, overrides=overrides)
 
     def __getitem__(self, item):
         return self.d[item]

SCons/Environment.py

@@ -481,7 +481,7 @@ def gvars(self):
     def lvars(self):
         return {}
 
-    def subst(self, string, raw=0, target=None, source=None, conv=None, executor=None):
+    def subst(self, string, raw=0, target=None, source=None, conv=None, executor=None, overrides=False):
         """Recursively interpolates construction variables from the
         Environment into the specified string, returning the expanded
         result.  Construction variables are specified by a $ prefix
@@ -496,7 +496,7 @@ def subst(self, string, raw=0, target=None, source=None, conv=None, executor=Non
         lvars['__env__'] = self
         if executor:
             lvars.update(executor.get_lvars())
-        return SCons.Subst.scons_subst(string, self, raw, target, source, gvars, lvars, conv)
+        return SCons.Subst.scons_subst(string, self, raw, target, source, gvars, lvars, conv, overrides=overrides)
 
     def subst_kw(self, kw, raw=0, target=None, source=None):
         nkw = {}
@@ -507,15 +507,15 @@ def subst_kw(self, kw, raw=0, target=None, source=None):
             nkw[k] = v
         return nkw
 
-    def subst_list(self, string, raw=0, target=None, source=None, conv=None, executor=None):
+    def subst_list(self, string, raw=0, target=None, source=None, conv=None, executor=None, overrides=False):
         """Calls through to SCons.Subst.scons_subst_list().  See
         the documentation for that function."""
         gvars = self.gvars()
         lvars = self.lvars()
         lvars['__env__'] = self
         if executor:
             lvars.update(executor.get_lvars())
-        return SCons.Subst.scons_subst_list(string, self, raw, target, source, gvars, lvars, conv)
+        return SCons.Subst.scons_subst_list(string, self, raw, target, source, gvars, lvars, conv, overrides=overrides)
 
     def subst_path(self, path, target=None, source=None):
         """Substitute a path list, turning EntryProxies into Nodes

SCons/Subst.py

@@ -804,7 +804,8 @@ def _remove_list(list):
 # space characters in the string result from the scons_subst() function.
 _space_sep = re.compile(r'[\t ]+(?![^{]*})')
 
-def scons_subst(strSubst, env, mode=SUBST_RAW, target=None, source=None, gvars={}, lvars={}, conv=None):
+
+def scons_subst(strSubst, env, mode=SUBST_RAW, target=None, source=None, gvars={}, lvars={}, conv=None, overrides=False):
     """Expand a string or list containing construction variable
     substitutions.
 
@@ -834,6 +835,10 @@ def scons_subst(strSubst, env, mode=SUBST_RAW, target=None, source=None, gvars={
             lvars = lvars.copy()
             lvars.update(d)
 
+    # Allow last ditch chance to override lvars
+    if overrides:
+        lvars.update(overrides)
+
     # We're (most likely) going to eval() things.  If Python doesn't
     # find a __builtins__ value in the global dictionary used for eval(),
     # it copies the current global values for you.  Avoid this by
@@ -882,7 +887,7 @@ def scons_subst(strSubst, env, mode=SUBST_RAW, target=None, source=None, gvars={
 
     return result
 
-def scons_subst_list(strSubst, env, mode=SUBST_RAW, target=None, source=None, gvars={}, lvars={}, conv=None):
+def scons_subst_list(strSubst, env, mode=SUBST_RAW, target=None, source=None, gvars={}, lvars={}, conv=None,overrides=False):
     """Substitute construction variables in a string (or list or other
     object) and separate the arguments into a command list.
 
@@ -908,6 +913,10 @@ def scons_subst_list(strSubst, env, mode=SUBST_RAW, target=None, source=None, gv
             lvars = lvars.copy()
             lvars.update(d)
 
+    # Allow caller to specify last ditch override of lvars
+    if overrides:
+        lvars.update(overrides)
+
     # We're (most likely) going to eval() things.  If Python doesn't
     # find a __builtins__ value in the global dictionary used for eval(),
     # it copies the current global values for you.  Avoid this by

SCons/SubstTests.py

@@ -713,6 +713,14 @@ def test_CLVar(self):
         assert cmd_list[0][3] == "call", cmd_list[0][3]
         assert cmd_list[0][4] == "test", cmd_list[0][4]
 
+
+    def test_subst_overriding_lvars_overrides(self):
+        """Test that optional passed arg overrides overrides gvars, and existing lvars."""
+        env=DummyEnv({'XXX' : 'xxx'})
+        result = scons_subst('$XXX', env, gvars=env.Dictionary(), overrides={'XXX': 'yyz'})
+        assert result == 'yyz', result
+
+
 class scons_subst_list_TestCase(SubstTestCase):
 
     basic_cases = [
@@ -1102,6 +1110,13 @@ def test_subst_list_overriding_gvars2(self):
         result = scons_subst_list('$XXX', env, gvars={'XXX' : 'yyy'})
         assert result == [['yyy']], result
 
+    def test_subst_list_overriding_lvars_overrides(self):
+        """Test that optional passed arg overrides overrides gvars, and existing lvars."""
+        env = DummyEnv({'XXX':'xxx'})
+        result = scons_subst_list('$XXX', env, gvars=env.Dictionary(), overrides={'XXX': 'yyy'})
+        assert result == [['yyy']], result
+
+
 class scons_subst_once_TestCase(unittest.TestCase):
 
     loc = {

SCons/Tool/compilation_db.py

@@ -34,6 +34,8 @@
 import fnmatch
 import SCons
 
+from SCons.Platform import TempFileMunge
+
 from .cxx import CXXSuffixes
 from .cc import CSuffixes
 from .asm import ASSuffixes, ASPPSuffixes
@@ -53,6 +55,7 @@ def __init__(self, value):
         SCons.Node.Python.Value.__init__(self, value)
         self.Decider(changed_since_last_build_node)
 
+
 def changed_since_last_build_node(child, target, prev_ni, node):
     """ Dummy decider to force always building"""
     return True
@@ -103,6 +106,11 @@ def emit_compilation_db_entry(target, source, env):
     return emit_compilation_db_entry
 
 
+class CompDBTEMPFILE(TempFileMunge):
+    def __call__(self, target, source, env, for_signature):
+        return self.cmd
+
+
 def compilation_db_entry_action(target, source, env, **kw):
     """
     Create a dictionary with evaluated command line, target, source
@@ -119,6 +127,7 @@ def compilation_db_entry_action(target, source, env, **kw):
         target=env["__COMPILATIONDB_UOUTPUT"],
         source=env["__COMPILATIONDB_USOURCE"],
         env=env["__COMPILATIONDB_ENV"],
+        overrides={'TEMPFILE': CompDBTEMPFILE}
     )
 
     entry = {