Hi Gábor, On Wed, 23 Oct 2019, SZEDER Gábor wrote: > On Wed, Oct 23, 2019 at 07:22:12AM +0000, Aleksey Mikhaylov wrote: > > "Could not access submodule" error when pulling recursively with Git 2.22.0. > > This issue causes if there is submodule in submodule. > > > Please use my simple test repository to reproduce the problem: > > https://github.com/agmikhailov/example2361.git > > > > It is just an empty repository with one submodule (https://github.com/agmikhailov/example2361M1.git) > > and one submodule of submodule (https://github.com/agmikhailov/example2361M2.git): > > > > git clone https://github.com/agmikhailov/example2361.git > > cd example2361/ > > git submodule init > > According to the docs of 'git submodule init', it "initializes the > submodules recorded in the index". Therefore, it can only initialize > the submodule in 'example2361M1', because at this point we have no > idea that there is a nested submodule in there. > > $ git submodule init > Submodule 'example2361M1' (https://github.com/agmikhailov/example2361M1.git) registered for path 'example2361M1' Indeed, `git submodule init` is not recursive. > > git submodule update > > This command clones 'example2361M1': > > $ git submodule update --recursive > Cloning into '/tmp/example2361/example2361M1'... > Submodule path 'example2361M1': checked out '6a9be24a1c0ebd44d91ae4dcf1fd62580b936540' > > Only at this point can we finally see that there is a nested > submodule, and can initialize and clone it with: > > $ cd example2361M1 > $ git submodule init > Submodule 'example2361M2' (https://github.com/agmikhailov/example2361M2.git) registered for path 'example2361M2' > $ git submodule update > Cloning into '/tmp/example2361/example2361M1/example2361M2'... > Submodule path 'example2361M2': checked out '9ed39cf1fe0a8cf34e72d2e7ebff1ea9d4a63ac1' I concur. > > git pull --recurse-submodules=true > > And after that: > > $ cd ../.. > $ git pull --recurse-submodules=true > Fetching submodule example2361M1 > Fetching submodule example2361M1/example2361M2 > Already up to date. Yes, I agree that _probably_ what the user wanted is to initialize the submodules recursively. Having said that, I vaguely remember that e.g. Boost has this insane forest of submodules, and I am almost certain that no sane person wants to clone them all. _I_ wouldn't. > > ACTUAL RESULT > > > > "git --recurse-submodules=true" command fails with message "Could not access submodule": > > > > $ git --recurse-submodules=true > > Fetching submodule example2361M1 > > Could not access submodule 'example2361M2' > > > > EXPECTED RESULT > > > > All submodules are successfully updated by "git --recurse-submodules=true" command. > > > > ADDITIONAL INFORMATION > > > > Git version 2.20.1 does not have this problem. > > So we had to downgrade Git to work with submodules. > > The behavior was indeed different with v2.20.1, but that version > didn't show the behavior you expected. When running your commands > with v2.20.1 I get: > > $ ~/src/git/bin-wrappers/git pull --recurse-submodules=true > Fetching submodule example2361M1 > Already up to date. > $ find example2361M1/example2361M2/ > example2361M1/example2361M2/ > > So while that 'git pull' didn't error out, it didn't even look at the > nested submodule, which is still uninitialized and empty. I would actually argue that this is what is expected: the entire _point_ of submodules is that they can be inactive. Coming back to the Boost example, what I would want Git to do when only a fraction of the submodules is active is to skip the inactive ones during a `git pull --recurse-submodules=true`. Which v2.20.1 apparently did, and I would call the current behavior a regression. > FWIW, bisecting shows that the behavior changed with commit > a62387b3fc, Thanks for digging this out! > but, unfortunately, the commit message doesn't seem to be very helpful > to me, but perhaps others with more experience with submodules can > make something out of it. > > commit a62387b3fc9f5aeeb04a2db278121d33a9caafa7 > Author: Stefan Beller <sbeller@xxxxxxxxxx> > Date: Wed Nov 28 16:27:55 2018 -0800 > > submodule.c: fetch in submodules git directory instead of in worktree > > Keep the properties introduced in 10f5c52656 (submodule: avoid > auto-discovery in prepare_submodule_repo_env(), 2016-09-01), by fixating > the git directory of the submodule. > > Signed-off-by: Stefan Beller <sbeller@xxxxxxxxxx> > Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx> > > submodule.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) To me, this commit message suggests that the bahvior should not have changed in the reported manner. Let's look at the diff: -- snip -- diff --git a/submodule.c b/submodule.c index 77ace5e784a..d1b6646f42d 100644 --- a/submodule.c +++ b/submodule.c @@ -494,6 +494,12 @@ void prepare_submodule_repo_env(struct argv_array *out) DEFAULT_GIT_DIR_ENVIRONMENT); } +static void prepare_submodule_repo_env_in_gitdir(struct argv_array *out) +{ + prepare_submodule_repo_env_no_git_dir(out); + argv_array_pushf(out, "%s=.", GIT_DIR_ENVIRONMENT); +} + /* Helper function to display the submodule header line prior to the full * summary output. If it can locate the submodule objects directory it will * attempt to lookup both the left and right commits and put them into the @@ -1327,8 +1333,8 @@ static int get_next_submodule(struct child_process *cp, repo = get_submodule_repo_for(spf->r, submodule); if (repo) { child_process_init(cp); - cp->dir = xstrdup(repo->worktree); - prepare_submodule_repo_env(&cp->env_array); + cp->dir = xstrdup(repo->gitdir); + prepare_submodule_repo_env_in_gitdir(&cp->env_array); cp->git_cmd = 1; if (!spf->quiet) strbuf_addf(err, "Fetching submodule %s%s\n", -- snap -- The obvious difference in behavior is that we no longer let Git discover the `.git` file/directory, but we define it (because we can). But actually, we cannot, not if the submodule is not checked out! Because in this case, there is no `.git` file and Git then tries to initialize the repository and the worktree, and fails rather miserably in the reported manner. Side note: I think there is something spooky going on where we try to fetch submodules twice when the first time failed, and somehow slip into the `else` arm of this code: -- snip -- task->repo = get_submodule_repo_for(spf->r, task->sub); if (task->repo) { struct strbuf submodule_prefix = STRBUF_INIT; child_process_init(cp); cp->dir = task->repo->gitdir; prepare_submodule_repo_env_in_gitdir(&cp->env_array); cp->git_cmd = 1; if (!spf->quiet) strbuf_addf(err, "Fetching submodule %s%s\n", spf->prefix, ce->name); argv_array_init(&cp->args); argv_array_pushv(&cp->args, spf->args.argv); argv_array_push(&cp->args, default_argv); argv_array_push(&cp->args, "--submodule-prefix"); strbuf_addf(&submodule_prefix, "%s%s/", spf->prefix, task->sub->path); argv_array_push(&cp->args, submodule_prefix.buf); spf->count++; *task_cb = task; strbuf_release(&submodule_prefix); return 1; } else { fetch_task_release(task); free(task); /* * An empty directory is normal, * the submodule is not initialized */ if (S_ISGITLINK(ce->ce_mode) && !is_empty_dir(ce->name)) { spf->result = 1; strbuf_addf(err, _("Could not access submodule '%s'"), ce->name); } } -- snap -- As you can see, at that point, `is_empty_dir()` indicates that it is _no longer empty_, which means that the recursive pull actually tried to initialize it, and left things in a half-consistent state. BTW I also think that Stefan's commit just made a bug very obvious that had not mattered all that much before: it would seem that before that commit, when the code tried to fetch a submodule, it would actually fetch the super project (because it would discover the .git file/directory, and as the inactive submodule does not have any, it would have found the super project's). In essence, I think that the report points out a very real bug, and this bug should be fixed. I _could_ imagine that it would be as easy as applying this patch (and turning the provided reproducer into a regression test), then polishing this with a nice commit message: -- snip -- diff --git a/submodule.c b/submodule.c index 0f199c51378..5694905610a 100644 --- a/submodule.c +++ b/submodule.c @@ -1443,6 +1443,12 @@ static int get_next_submodule(struct child_process *cp, task->repo = get_submodule_repo_for(spf->r, task->sub); if (task->repo) { struct strbuf submodule_prefix = STRBUF_INIT; + + /* skip uninitialized submodule */ + if (!file_exists(task->repo->gitdir) || + is_empty_dir(task->repo->gitdir)) + continue; + child_process_init(cp); cp->dir = task->repo->gitdir; prepare_submodule_repo_env_in_gitdir(&cp->env_array); -- snap -- Any takers? Ciao, Johannes
