Hello!
I'm trying to use subtrees. I've learned that there are two ways to go
about it: using 'git subtree', which I've decided against, or
"manually", which is what I'm doing.
When I try to merge a new commit from the "subtree" branch, I observe
all kinds of *silent* failures.
For example, there is a commit that removes three files in the subtree
directory.
- On my first attempt to merge it, it removed three completely different
files in another directory.
- On my second attempt, it removed only two of the three files.
- On my third attempt, it said that "Merge went well", but there was no
merge commit at all.
- On my fourth attempt, there was a commit, but it was empty (no changes).
In all cases, there was no warning, no output to notice that something
went wrong - it always seems "successful", so I have to double-check
everything. And this operation is as trivial as it gets - if even this
can't be handled reliably, then I can't imagine how do people use it. So
I guess I'm doing something wrong.
Here is an example. The Git version I'm using is 2.39.2 (Debian Bookworm).
# Create a new repo, add some files, add more files in 'utils/' subdirectory
$ git init
Initialized empty Git repository in /tmpfs/poc/.git/
$ touch a b c d e
$ git add ?
$ git commit -m "Initial commit"
[master (root-commit) 172da89] Initial commit
5 files changed, 0 insertions(+), 0 deletions(-)
create mode 100644 a
create mode 100644 b
create mode 100644 c
create mode 100644 d
create mode 100644 e
$ mkdir utils && cd utils
$ touch f g h
$ git add ?
$ git commit -m "Add utils"
[master 156233d] Add utils
3 files changed, 0 insertions(+), 0 deletions(-)
create mode 100644 utils/f
create mode 100644 utils/g
create mode 100644 utils/h
$ cd ..
# Split 'utils/' into a separate "subtree" branch
$ git checkout -b utils
Switched to a new branch 'utils'
$ git filter-branch --subdirectory-filter utils
Rewrite 156233d93120ccf4371dcd63cbcf1c5599c03abe (1/1) (0 seconds
passed, remaining 0 predicted)
Ref 'refs/heads/utils' was rewritten
$ ls -lh
total 0
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:26 f
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:26 g
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:26 h
$ git graph --oneline --decorate
* e9ef662 (HEAD -> utils) Add utils
$ git status
On branch utils
nothing to commit, working tree clean
# Update the 'utils' branch (mimick fetching the upstream branch)
$ touch x
$ git add x
$ git commit -m "Add x"
[utils 95deda7] Add x
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 x
$ touch y
$ git add y
$ git commit -m "Add y"
[utils e2dd4e2] Add y
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 y
$ touch z
$ git add z
$ git commit -m "Add z"
[utils b85ef2c] Add z
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 z
# Merge the updates into the master branch
$ git checkout master
Switched to branch 'master'
$ git merge -s subtree --allow-unrelated-histories --squash utils
Squash commit -- not updating HEAD
Automatic merge went well; stopped before committing as requested
$ git status
On branch master
Changes to be committed:
(use "git restore --staged <file>..." to unstage)
new file: utils/x
new file: utils/y
new file: utils/z
$ git commit
[master 90bffcb] Add x y z
3 files changed, 0 insertions(+), 0 deletions(-)
create mode 100644 utils/x
create mode 100644 utils/y
create mode 100644 utils/z
# Now update 'utils' again
$ git checkout utils
Switched to branch 'utils'
$ rm x y z
$ git commit -a
[utils 85e7775] Delete XYZ
3 files changed, 0 insertions(+), 0 deletions(-)
delete mode 100644 x
delete mode 100644 y
delete mode 100644 z
# And merge this update
$ git checkout master
Switched to branch 'master'
$ git merge -s subtree --allow-unrelated-histories --squash utils
Squash commit -- not updating HEAD
Automatic merge went well; stopped before committing as requested
# OK, everything went fine, now let's check and commit this:
$ git status
On branch master
nothing to commit, working tree clean
# WTF?
$ git graph --oneline --decorate
* 90bffcb (HEAD -> master) Add x y z
* 156233d (refs/original/refs/heads/utils) Add utils
* 172da89 Initial commit
# WTF???
$ git merge -s subtree --allow-unrelated-histories --squash utils
Squash commit -- not updating HEAD
Automatic merge went well; stopped before committing as requested
# But at least the files were removed, right?
$ ls -lha utils/
total 0
drwxr-xr-x 2 kami kami 160 29 Oct 2023 19:28 .
drwxr-xr-x 4 kami kami 180 29 Oct 2023 19:28 ..
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 f
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 g
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 h
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 x
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 y
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 z
# WTF??? OK, let's try passing the subtree prefix:
$ git merge -s subtree -X subtree=utils --allow-unrelated-histories
--squash utils
Squash commit -- not updating HEAD
Automatic merge went well; stopped before committing as requested
$ git status
On branch master
nothing to commit, working tree clean
# Let's try the default strategy with passing the subtree prefix?..
$ git merge -X subtree=utils --allow-unrelated-histories --squash utils
Squash commit -- not updating HEAD
Automatic merge went well; stopped before committing as requested
$ git status
On branch master
nothing to commit, working tree clean
$ git onegraph
* 90bffcb (HEAD -> master) Add x y z
* 156233d (refs/original/refs/heads/utils) Add utils
* 172da89 Initial commit
# Let's try without squashing?..
$ git merge -s subtree -X subtree=utils --allow-unrelated-histories utils
Merge made by the 'subtree' strategy.
$ git graph --oneline --decorate
* 9799659 (HEAD -> master) Merge branch 'utils'
|\
| * 85e7775 (utils) Delete XYZ
| * b85ef2c Add z
| * e2dd4e2 Add y
| * 95deda7 Add x
| * e9ef662 Add utils
* 90bffcb Add x y z
* 156233d (refs/original/refs/heads/utils) Add utils
* 172da89 Initial commit
# OK, now the commit is there. So files are deleted, right?
$ ls -lha utils/
total 0
drwxr-xr-x 2 kami kami 160 29 Oct 2023 19:28 .
drwxr-xr-x 4 kami kami 180 29 Oct 2023 19:28 ..
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 f
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 g
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 h
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 x
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 y
-rw-r--r-- 1 kami kami 0 29 Oct 2023 19:28 z
# Then what's in the commit?
$ git diff
$ git diff HEAD
$ git show
commit 97996594a7e527880389a2253ed8f887c130a070 (HEAD -> master)
Merge: 90bffcb 85e7775
Author: darkpenguin <darkpeng...@posteo.de>
Date: Sun Oct 29 19:29:34 2023 +0400
Merge branch 'utils'
# Nothing! OK, maybe there is something wrong with the commit I'm merging?
$ git checkout utils
Switched to branch 'utils'
$ git diff HEAD~1
diff --git a/x b/x
deleted file mode 100644
index e69de29..0000000
diff --git a/y b/y
deleted file mode 100644
index e69de29..0000000
diff --git a/z b/z
deleted file mode 100644
index e69de29..0000000
# No, files are definitely deleted in this commit. But they are not when
I merge it.
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