Easy way to pull latest of all git submodules

Question

We\'re using git submodules to manage a couple of large projects that have dependencies on many other libraries we\'ve developed. Each library is a separate repo brought int

Answer 1

Remark: not too easy way, but workable and it has its own unique pros.

If one want to clone only HEAD revision of a repository and only HEADs of all the its submodules (i.e. to checkout "trunk"), then one can use following Lua script. Sometimes simple command git submodule update --init --recursive --remote --no-fetch --depth=1 can result in an unrecoverable git error. In this case one need to clean up subdirectory of .git/modules directory and clone submodule manually using git clone --separate-git-dir command. The only complexity is to find out URL, path of .git directory of submodule and path of submodule in superproject tree.

Remark: the script is only tested against https://github.com/boostorg/boost.git repository. Its peculiarities: all the submodules hosted on the same host and .gitmodules contains only relative URLs.

-- mkdir boost ; cd boost ; lua ../git-submodules-clone-HEAD.lua https://github.com/boostorg/boost.git .
local module_url = arg[1] or 'https://github.com/boostorg/boost.git'
local module = arg[2] or module_url:match('.+/([_%d%a]+)%.git')
local branch = arg[3] or 'master'
function execute(command)
    print('# ' .. command)
    return os.execute(command)
end
-- execute('rm -rf ' .. module)
if not execute('git clone --single-branch --branch master --depth=1 ' .. module_url .. ' ' .. module) then
    io.stderr:write('can\'t clone repository from ' .. module_url .. ' to ' .. module .. '\n')
    return 1
end
-- cd $module ; git submodule update --init --recursive --remote --no-fetch --depth=1
execute('mkdir -p ' .. module .. '/.git/modules')
assert(io.input(module .. '/.gitmodules'))
local lines = {}
for line in io.lines() do
    table.insert(lines, line)
end
local submodule
local path
local submodule_url
for _, line in ipairs(lines) do
    local submodule_ = line:match('^%[submodule %"([_%d%a]-)%"%]$')
    if submodule_ then
        submodule = submodule_
        path = nil
        submodule_url = nil
    else
        local path_ = line:match('^%s*path = (.+)$')
        if path_ then
            path = path_
        else
            submodule_url = line:match('^%s*url = (.+)$')
        end
        if submodule and path and submodule_url then
            -- execute('rm -rf ' .. path)
            local git_dir = module .. '/.git/modules/' .. path:match('^.-/(.+)$')
            -- execute('rm -rf ' .. git_dir)
            execute('mkdir -p $(dirname "' .. git_dir .. '")')
            if not execute('git clone --depth=1 --single-branch --branch=' .. branch .. ' --separate-git-dir ' .. git_dir .. ' ' .. module_url .. '/' .. submodule_url .. ' ' .. module .. '/' .. path) then
                io.stderr:write('can\'t clone submodule ' .. submodule .. '\n')
                return 1
            end
            path = nil
            submodule_url = nil
        end
    end
end