build: make git sub-modules to fetch configurable

Currently the git protocol downloads all submodules of the target
repository. This can be unwieldy for repositories with a lot of submodules
where only a subset are required in the context of the OpenWrt build.

This change adds a PKG_SOURCE_SUBMODULES variable to configure this
behavior. It takes a space-separated list of submodule paths, or the word
"skip" to disable submodule downloads entirely. The default is to download
all submodules, i.e. preserving current behavior.

Signed-off-by: Karsten Sperling <ksperling@apple.com>

include/download.mk

@@ -209,6 +209,7 @@ define DownloadMethod/github_archive
 			--subdir="$(SUBDIR)" \
 			--source="$(FILE)" \
 			--hash="$(MIRROR_HASH)" \
+			--submodules $(SUBMODULES) \
 		|| ( $(call DownloadMethod/rawgit) ); \
 	)
 endef
@@ -222,7 +223,7 @@ define DownloadMethod/rawgit
 	[ \! -d $(SUBDIR) ] && \
 	git clone $(OPTS) $(URL) $(SUBDIR) && \
 	(cd $(SUBDIR) && git checkout $(VERSION) && \
-	git submodule update --init --recursive) && \
+	$(if $(filter skip,$(SUBMODULES)),true,git submodule update --init --recursive -- $(SUBMODULES))) && \
 	echo "Packing checkout..." && \
 	export TAR_TIMESTAMP=`cd $(SUBDIR) && git log -1 --format='@%ct'` && \
 	rm -rf $(SUBDIR)/.git && \
@@ -301,6 +302,7 @@ define Download/Defaults
   MIRROR_MD5SUM:=x
   VERSION:=
   OPTS:=
+  SUBMODULES:=
 endef
 
 define Download/default
@@ -309,6 +311,7 @@ define Download/default
   URL_FILE:=$(PKG_SOURCE_URL_FILE)
   SUBDIR:=$(PKG_SOURCE_SUBDIR)
   PROTO:=$(PKG_SOURCE_PROTO)
+  SUBMODULES:=$(PKG_SOURCE_SUBMODULES)
   $(if $(PKG_SOURCE_MIRROR),MIRROR:=$(filter 1,$(PKG_MIRROR)))
   $(if $(PKG_MIRROR_MD5SUM),MIRROR_MD5SUM:=$(PKG_MIRROR_MD5SUM))
   $(if $(PKG_MIRROR_HASH),MIRROR_HASH:=$(PKG_MIRROR_HASH))

scripts/dl_github_archive.py

@@ -239,6 +239,7 @@ class DownloadGitHubTarball(object):
         self.version = args.version
         self.subdir = args.subdir
         self.source = args.source
+        self.submodules = args.submodules
         self.url = args.url
         self._init_owner_repo()
         self.xhash = args.hash
@@ -249,6 +250,8 @@ class DownloadGitHubTarball(object):
 
     def download(self):
         """Download and repack GitHub archive tarball."""
+        if self.submodules and self.submodules != ['skip']:
+            raise self._error('Fetching submodules is not yet supported')
         self._init_commit_ts()
         with Path(TMPDIR_DL, keep=True) as dir_dl:
             # fetch tarball from GitHub
@@ -262,7 +265,7 @@ class DownloadGitHubTarball(object):
                     dir0 = os.path.join(dir_untar.path, tarball_prefix)
                     dir1 = os.path.join(dir_untar.path, self.subdir)
                     # submodules check
-                    if self._has_submodule(dir0):
+                    if self.submodules != ['skip'] and self._has_submodule(dir0):
                         raise self._error('Fetching submodules is not yet supported')
                     # rename subdir
                     os.rename(dir0, dir1)
@@ -415,6 +418,7 @@ def main():
     parser.add_argument('--version', help='Source code version')
     parser.add_argument('--source', help='Source tarball filename')
     parser.add_argument('--hash', help='Source tarball\'s expected sha256sum')
+    parser.add_argument('--submodules', nargs='*', help='List of submodules, or "skip"')
     args = parser.parse_args()
     try:
         method = DownloadGitHubTarball(args)