Warn about strip extras by default

README.md

@@ -564,9 +564,12 @@ This section lists `pip-tools` features that are currently deprecated.
 - In the next major release, the `--allow-unsafe` behavior will be enabled by
   default (https://github.com/jazzband/pip-tools/issues/989).
   Use `--no-allow-unsafe` to keep the old behavior. It is recommended
-  to pass the `--allow-unsafe` now to adapt to the upcoming change.
+  to pass `--allow-unsafe` now to adapt to the upcoming change.
 - The legacy resolver is deprecated and will be removed in future versions.
   The new default is `--resolver=backtracking`.
+- In the next major release, the `--strip-extras` behavior will be enabled by
+  default (https://github.com/jazzband/pip-tools/issues/1613).
+  Use `--no-strip-extras` to keep the old behavior.
 
 ### A Note on Resolvers
 

piptools/scripts/compile.py

@@ -226,9 +226,9 @@ def _determine_linesep(
     ),
 )
 @click.option(
-    "--strip-extras",
+    "--strip-extras/--no-strip-extras",
     is_flag=True,
-    default=False,
+    default=None,
     help="Assure output file is constraints compatible, avoiding use of extras.",
 )
 @click.option(
@@ -365,7 +365,7 @@ def cli(
     output_file: LazyFile | IO[Any] | None,
     newline: str,
     allow_unsafe: bool,
-    strip_extras: bool,
+    strip_extras: bool | None,
     generate_hashes: bool,
     reuse_hashes: bool,
     src_files: tuple[str, ...],
@@ -676,6 +676,15 @@ def cli(
         strategy=newline, filenames=(output_file.name, *src_files)
     )
 
+    if strip_extras is None:
+        strip_extras = False
+        log.warning(
+            "WARNING: --strip-extras is becoming the default. "
+            "To silence this warning, "
+            "either use --strip-extras to opt into the new default "
+            "or use --no-strip-extras to retain the existing behavior."
+        )
+
     ##
     # Output
     ##