Allow the use of the underscore symbol in the "keywords" field

HISTORY.rst

@@ -20,6 +20,7 @@ PlatformIO Core 6
 
 * Added a new ``--lint`` option to the `pio project config <https://docs.platformio.org/en/latest/core/userguide/project/cmd_config.html>`__ command, enabling users to efficiently perform linting on the |PIOCONF|
 * Enhanced the parsing of the |PIOCONF| to provide comprehensive diagnostic information
+* Expanded the functionality of the |LIBRARYJSON| manifest by allowing the use of the underscore symbol in the `keywords <https://docs.platformio.org/en/latest/manifests/library-json/fields/keywords.html>`__ field
 * Optimized project integration templates to address the issue of long paths on Windows (`issue #4652 <https://github.com/platformio/platformio-core/issues/4652>`_)
 * Refactored |UNITTESTING| engine to resolve compiler warnings with "-Wpedantic" option (`pull #4671 <https://github.com/platformio/platformio-core/pull/4671>`_)
 * Eliminated erroneous warning regarding the use of obsolete PlatformIO Core when downgrading to the stable version (`issue #4664 <https://github.com/platformio/platformio-core/issues/4664>`_)

platformio/package/manifest/schema.py

@@ -183,7 +183,7 @@ class ManifestSchema(BaseSchema):
             validate=[
                 validate.Length(min=1, max=50),
                 validate.Regexp(
-                    r"^[a-z\d\-\+\. ]+$", error="Only [a-z0-9-+. ] chars are allowed"
+                    r"^[a-z\d\-_\+\. ]+$", error="Only [a-z0-9+_-. ] chars are allowed"
                 ),
             ]
         )

tests/package/test_manifest.py

@@ -28,7 +28,7 @@ def test_library_json_parser():
     contents = """
 {
     "name": "TestPackage",
-    "keywords": "kw1, KW2, kw3, KW2",
+    "keywords": "kw1, KW2, kw3, KW2, kw 4, kw_5, kw-6",
     "headers": "include1.h, Include2.hpp",
     "platforms": ["atmelavr", "espressif"],
     "repository": {
@@ -62,7 +62,7 @@ def test_library_json_parser():
                 "url": "https://github.com/username/repo.git",
             },
             "export": {"exclude": [".gitignore", "tests"], "include": ["mylib"]},
-            "keywords": ["kw1", "kw2", "kw3"],
+            "keywords": ["kw1", "kw2", "kw3", "kw 4", "kw_5", "kw-6"],
             "headers": ["include1.h", "Include2.hpp"],
             "homepage": "http://old.url.format",
             "build": {"flags": ["-DHELLO"]},