build: 1MB blob checked into tree, rewrite history again?

[bradfitz]

https://go-review.googlesource.com/c/go/+/151318 just added a 1MB blob to the git history.

It's new so a rewrite wouldn't be as painful as #28899.

Should we?

/cc @randall77 @mdempsky @dmitshur @bcmills @ianlancetaylor

[mdempsky]

Oops.

Have we rewritten before? Was there any unexpected downstream breakage?

I'm okay with rewriting, but admittedly I'm unlikely to deal with any fallout myself.

[bradfitz]

@mdempsky, we're up to maybe 4 rewrites. One was the other day.

Another bump on #10658 which I might do myself at this point.

[mdempsky]

SGTM

[andybons]

LGTM

[randall77]

What the heck did I do to make that blob? It doesn't appear in my client anywhere. But it does show up on Gerrit.

[randall77]

Nevermind, it is there. Looks like when I added the directory it also added my test binary in that directory.

[bradfitz]

Done.

$ cat rewrite-28962.sh
#!/bin/bash

set -e

git checkout master
git branch -D rewrite_28962 || true
git change rewrite_28962
git fetch origin
git reset --hard origin/master
OLD_HEAD=$(git rev-parse HEAD)

# The commit with the bad blob.
BAD=7dc5c0f041b84ca46de54d0e0bc688069bbe8ca3

echo "Old history:"
git log --format=oneline $BAD^..HEAD

git filter-branch --force --index-filter \
    'git rm --cached --ignore-unmatch test/fixedbugs/issue23311.dir/issue23311.dir' \
    -- $BAD^..HEAD

NEW_HEAD=$(git rev-parse HEAD)
echo "Moving from $OLD_HEAD to $NEW_HEAD ..."

# Should print:
#  test/fixedbugs/issue23311.dir/issue23311.dir | Bin 10207870 -> 0 bytes
git diff $OLD_HEAD --stat

# Then a force push to gerrit & github.
echo "If it all looks good, run:"
echo "$ git push --force-with-lease https://go.googlesource.com/go HEAD:refs/heads/master"
echo "$ git push --force-with-lease git@github.com:golang/go.git HEAD:refs/heads/master"


bradfitz@gdev:~/go$ ./rewrite-28962.sh
Switched to branch 'master'
Your branch is up to date with 'origin/master'.
Deleted branch rewrite_28962 (was 984be3b0f8).
/home/bradfitz/bin/git-codereview: created branch rewrite_28962 tracking origin/master.
HEAD is now at 73466e6bf5 go/internal/gccgoimporter: enhance for new export data, fix test issues
Old history:
73466e6bf56d1a9375dbffa8a89e20fb056358e9 (HEAD -> rewrite_28962, origin/master, origin/HEAD, refs/original/refs/heads/rewrite_28962, master) go/internal/gccgoimporter: enhance for new export data, fix test issues
7dc5c0f041b84ca46de54d0e0bc688069bbe8ca3 cmd/compile: allow bodyless function if it is linkname'd
Rewrite 7dc5c0f041b84ca46de54d0e0bc688069bbe8ca3 (1/2) (0 seconds passed, remaining 0 predicted)    rm 'test/fixedbugs/issue23311.dir/issue23311.dir'
Rewrite 73466e6bf56d1a9375dbffa8a89e20fb056358e9 (2/2) (0 seconds passed, remaining 0 predicted)    rm 'test/fixedbugs/issue23311.dir/issue23311.dir'

Ref 'refs/heads/rewrite_28962' was rewritten
Moving from 73466e6bf56d1a9375dbffa8a89e20fb056358e9 to 984be3b0f8388161e166039de8b7ac5383a76d10 ...
 test/fixedbugs/issue23311.dir/issue23311.dir | Bin 1093074 -> 0 bytes
 1 file changed, 0 insertions(+), 0 deletions(-)
If it all looks good, run:
$ git push --force-with-lease https://go.googlesource.com/go HEAD:refs/heads/master
$ git push --force-with-lease git@github.com:golang/go.git HEAD:refs/heads/master
bradfitz@gdev:~/go$ git push --force-with-lease https://go.googlesource.com/go HEAD:refs/heads/master
To https://go.googlesource.com/go
 ! [rejected]              HEAD -> master (stale info)
error: failed to push some refs to 'https://go.googlesource.com/go'
bradfitz@gdev:~/go$ git push --force https://go.googlesource.com/go HEAD:refs/heads/master
Enumerating objects: 52, done.
Counting objects: 100% (52/52), done.
Delta compression using up to 4 threads
Compressing objects: 100% (20/20), done.
Writing objects: 100% (29/29), 5.72 KiB | 2.86 MiB/s, done.
Total 29 (delta 21), reused 11 (delta 8)
remote: Resolving deltas: 100% (21/21)
remote: Processing changes: refs: 3, done    
To https://go.googlesource.com/go
 + 73466e6bf5...984be3b0f8 HEAD -> master (forced update)

[mdempsky]

1MB blob? What blob?

Oceania has always been at war with Eastasia.

[bradfitz]

And the gitmirror service is now restarted too.

[bradfitz]

I posted this comment on the wrong issue before. Repasting it here:

---

The only two CLs which were rewritten were:

https://go-review.googlesource.com/c/151318 (from 7dc5c0f to ca37492)
https://go-review.googlesource.com/c/149957 (from 73466e6 to 984be3b)