Add --emit-makefile option to list-dependent-make-targets

Author: colluca

src/pymakeutils/list_dependent_make_targets.py

@@ -4,6 +4,7 @@
 
 import argparse
 from pymakeutils.common import list_dependents
+import sys
 
 
 def parse_args():
@@ -18,6 +19,13 @@ def parse_args():
         '--recursive',
         action='store_true',
         help="Recursively include transitive dependents")
+    parser.add_argument(
+        '-M',
+        '--emit-makefrag',
+        action='store_true',
+        help="Instead of outputting a list of Make targets, emit a Makefile fragment "
+             "conditionally including each prerequisite if MAKE_CMD_GOALS includes "
+             "any of its dependent targets.")
     parser.add_argument(
         '-d',
         '--debug',
@@ -26,19 +34,38 @@ def parse_args():
     return parser.parse_args()
 
 
-def main():
-    args = parse_args()
+def emit_makefrag(prerequisites, recursive, debug):
+    s = "-include "
+    for p in sorted(set(prerequisites)):
+        targets = list_dependents(p, recursive=recursive, debug=debug)
+
+        if not targets:
+            print(f'Warning: no targets depend on prerequisite {p}.', file=sys.stderr)
+            continue
+
+        target_list = " ".join(sorted(targets))
+        s += f"$(if $(filter {target_list},$(MAKECMDGOALS)),{p}) "
+    print(s.strip())
 
+
+def emit_targets(prerequisites, recursive, debug):
     # Take the union of all dependent targets for the given prerequisites
     all_deps = set()
-    for p in args.prerequisites:
+    for p in prerequisites:
         all_deps.update(
-            list_dependents(p, recursive=args.recursive, debug=args.debug)
+            list_dependents(p, recursive=recursive, debug=debug)
         )
-    dependents = sorted(all_deps)
+    print('\n'.join(sorted(all_deps)))
+
+
+def main():
+    args = parse_args()
 
-    # Print the list of dependent targets
-    print('\n'.join(dependents))
+    if args.emit_makefrag:
+        emit = emit_makefrag
+    else:
+        emit = emit_targets
+    emit(args.prerequisites, args.recursive, args.debug)
 
 
 if __name__ == "__main__":