Make sure the extracted version starts with a digit

Signed-off-by: Keshav Priyadarshi <git@keshav.space>

Author: keshav-space

src/fetchcode/package.py

@@ -670,7 +670,7 @@ def get_packages_from_listing(purl, source_archive_url, regex, ignored_files_and
 
         version = match.group("version")
         version = version.strip("v").strip()
-        if not version:
+        if not version or not version[0].isdigit():
             continue
 
         modified_time = file.modified

src/fetchcode/package_util.py

@@ -127,7 +127,7 @@ def _get_github_packages(purl, version_regex, ignored_tag_regex, default_package
             version = tag
 
         version = version.strip("Vv").strip()
-        if not version:
+        if not version or not version[0].isdigit():
             continue
 
         download_url = archive_download_url.format(

tests/data/package/dirlisting/generic/busybox-expected.json

@@ -4642,41 +4642,5 @@
         "repository_homepage_url": null,
         "repository_download_url": null,
         "api_data_url": null
-    },
-    {
-        "type": "generic",
-        "namespace": null,
-        "name": "busybox",
-        "version": "snapshot",
-        "qualifiers": {},
-        "subpath": null,
-        "primary_language": null,
-        "description": null,
-        "release_date": "2024-03-04T00:20:00",
-        "parties": [],
-        "keywords": [],
-        "homepage_url": "https://www.busybox.net/downloads/",
-        "download_url": "https://www.busybox.net/downloads/busybox-snapshot.tar.bz2",
-        "api_url": null,
-        "size": null,
-        "sha1": null,
-        "md5": null,
-        "sha256": null,
-        "sha512": null,
-        "bug_tracking_url": null,
-        "code_view_url": null,
-        "vcs_url": null,
-        "copyright": null,
-        "license_expression": null,
-        "declared_license": null,
-        "notice_text": null,
-        "root_path": null,
-        "dependencies": [],
-        "contains_source_code": null,
-        "source_packages": [],
-        "purl": "pkg:generic/busybox@snapshot",
-        "repository_homepage_url": null,
-        "repository_download_url": null,
-        "api_data_url": null
     }
 ]

tests/data/package/dirlisting/generic/bzip2-expected.json

@@ -322,41 +322,5 @@
         "repository_homepage_url": null,
         "repository_download_url": null,
         "api_data_url": null
-    },
-    {
-        "type": "generic",
-        "namespace": null,
-        "name": "bzip2",
-        "version": "latest",
-        "qualifiers": {},
-        "subpath": null,
-        "primary_language": null,
-        "description": null,
-        "release_date": "2019-07-13T17:50:00",
-        "parties": [],
-        "keywords": [],
-        "homepage_url": "https://sourceware.org/pub/bzip2/",
-        "download_url": "https://sourceware.org/pub/bzip2/bzip2-latest.tar.gz",
-        "api_url": null,
-        "size": null,
-        "sha1": null,
-        "md5": null,
-        "sha256": null,
-        "sha512": null,
-        "bug_tracking_url": null,
-        "code_view_url": null,
-        "vcs_url": null,
-        "copyright": null,
-        "license_expression": null,
-        "declared_license": null,
-        "notice_text": null,
-        "root_path": null,
-        "dependencies": [],
-        "contains_source_code": null,
-        "source_packages": [],
-        "purl": "pkg:generic/bzip2@latest",
-        "repository_homepage_url": null,
-        "repository_download_url": null,
-        "api_data_url": null
     }
 ]