tools: make v run cmd/tools/oldv.v 5b7a1e8 -c "./v version" faster …

…(5b7a1e8 is the oldest supported commit from 2019-06-29)

cmd/tools/modules/vgit/vgit.v

@@ -81,8 +81,35 @@ pub fn clone_or_pull(remote_git_url string, local_worktree_path string) {
 		scripting.run('git -C "${local_worktree_path}"  checkout --quiet master')
 		scripting.run('git -C "${local_worktree_path}"  pull     --quiet ')
 	} else {
-		// Clone a fresh
-		scripting.run('git clone --filter=blob:none --quiet "${remote_git_url}"  "${local_worktree_path}" ')
+		// Clone a fresh local tree.
+		if remote_git_url.starts_with('http') {
+			// cloning an https remote with --filter=blob:none is usually much less bandwidth intensive, at the
+			// expense of doing small network ops later when using checkouts.
+			scripting.run('git clone --filter=blob:none --quiet "${remote_git_url}"  "${local_worktree_path}" ')
+			return
+		}
+		mut is_blobless_clone := false
+		remote_git_config_path := os.join_path(remote_git_url, '.git', 'config')
+		if os.is_dir(remote_git_url) && os.is_file(remote_git_config_path) {
+			lines := os.read_lines(remote_git_config_path) or { [] }
+			is_blobless_clone = lines.filter(it.contains('partialclonefilter = blob:none')).len > 0
+		}
+		if is_blobless_clone {
+			// Note:
+			// 1) cloning a *local folder* with `--filter=blob:none`, that *itself* was cloned with `--filter=blob:none`
+			// leads to *extremely* slow checkouts for older commits later. It takes hours instead of milliseconds, for a commit
+			// that is just several thousands of commits old :( .
+			//
+			// 2) Cloning it *without* the `--filter=blob:none`, leads to `error: unable to read sha1 file of`, later,
+			// when checking out the older commits, depending on the local git client version (tested with git version 2.41.0).
+			//
+			// 3) => instead of cloning, it is much faster, and *bug free*, to just rsync the local repo directly,
+			// at the expense of a little more space usage, which will make the new tree in local_worktree_path,
+			// exactly 1:1 the same, as the one in remote_git_url, just independent from it .
+			scripting.run('rsync -a "${remote_git_url}/"  "${local_worktree_path}/"')
+			return
+		}
+		scripting.run('git clone --quiet "${remote_git_url}"  "${local_worktree_path}" ')
 	}
 }
 

cmd/tools/oldv.v

@@ -83,7 +83,11 @@ fn sync_cache() {
 		repofolder := os.join_path(cache_oldv_folder, reponame)
 		if !os.exists(repofolder) {
 			scripting.verbose_trace(@FN, 'cloning to ${repofolder}')
-			scripting.exec('git clone --filter=blob:none --quiet https://github.com/vlang/${reponame} ${repofolder}') or {
+			mut repo_options := ''
+			if reponame == 'vc' {
+				repo_options = '--filter=blob:none'
+			}
+			scripting.exec('git clone ${repo_options} --quiet https://github.com/vlang/${reponame} ${repofolder}') or {
 				scripting.verbose_trace(@FN, '## error during clone: ${err}')
 				exit(1)
 			}