Use collected or project file depending if collector enabled.

If the collector is enabled (PIPELINE_COLLECTOR_ENABLED is True), use
the collected file. If the disabled (False), use the original project
source file to check if it is outdated and pick up the changes.

This will allow for static files (in particular less CSS compiler) files
to do relative imports from different apps.

See: jazzband#749

pipeline/compilers/__init__.py

@@ -32,10 +32,12 @@ def _compile(input_path):
                         infile = self.storage.path(input_path)
                     except NotImplementedError:
                         infile = finders.find(input_path)
-                    project_infile = finders.find(input_path)
                     outfile = compiler.output_path(infile, compiler.output_extension)
-                    outdated = compiler.is_outdated(project_infile, outfile)
-                    compiler.compile_file(project_infile, outfile,
+                    if not settings.PIPELINE_COLLECTOR_ENABLED:
+                        # override the input file with the original source from the project
+                        infile = finders.find(input_path)
+                    outdated = compiler.is_outdated(infile, outfile)
+                    compiler.compile_file(infile, outfile,
                                           outdated=outdated, force=force,
                                           **compiler_options)