git-svn adding too many blank lines during git-cherry-pick, and git-cherry getting confused

git-svn adding too many blank lines during git-cherry-pick, and git-cherry getting confused

[Robin H. Johnson]

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Hi,

Bit of weirdness I ran into.

I have a SVN tree, with a branch that gets some backported fixe (they
usually apply cleanly).

I commit the fix to the trunk + git-svn dcommit, and then switch to the
other branch, and git-cherry-pick the fix.

For git-svn commits, the log has:
On the trunk side, there is a two blank line before git-svn-id.
On the branch side, there are three blank lines before git-svn-id.
If I cherry-pick from that branch to a third branch, I get 4 blank
lines.

For regular SVN commits, the log has:
Only a single blank line before git-svn-id.

I think the source of the problem is that git-svn-id is being removed
when cherry-picking, but NOT the leading blank line.

This all leads to the hashes of the commits diverging badly, and then
git-cherry gets very confused when asked to compare the trunk vs. the
branches.

How do we solve it?
This is only on a conceptual level here, looking at the present state of
git-svn, I'm not sure how best to solve it.

git-svn fetch:
1. Get commit message from SVN. 
2. Trim ALL trailing blank lines (and existing git-svn-id lines).
3. If the last line was header-style (Signed-off-by, CC, etc)
3.1. if it was, do not add a blank line.
3.2. If not, add a single blank line.
4. Insert git-svn-id header.

git-svn dcommit:
1. Get commit message (git cat-file commit ....)
2. Remove the git-svn-id line.
3. Remove all trailing blank lines.
4. Commit.

-- 
Robin Hugh Johnson
Gentoo Linux Developer & Council Member
E-Mail     : robbat2@gentoo.org
GnuPG FP   : 11AC BA4F 4778 E3F6 E4ED  F38E B27B 944E 3488 4E85

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Re: git-svn adding too many blank lines during git-cherry-pick, and git-cherry getting confused

[Eric Wong]

"Robin H. Johnson" <robbat2@gentoo.org> wrote:
> Hi,
> 
> Bit of weirdness I ran into.
> 
> I have a SVN tree, with a branch that gets some backported fixe (they
> usually apply cleanly).
> 
> I commit the fix to the trunk + git-svn dcommit, and then switch to the
> other branch, and git-cherry-pick the fix.
> 
> For git-svn commits, the log has:
> On the trunk side, there is a two blank line before git-svn-id.
> On the branch side, there are three blank lines before git-svn-id.
> If I cherry-pick from that branch to a third branch, I get 4 blank
> lines.
> 
> For regular SVN commits, the log has:
> Only a single blank line before git-svn-id.
> 
> I think the source of the problem is that git-svn-id is being removed
> when cherry-picking, but NOT the leading blank line.
> 
> This all leads to the hashes of the commits diverging badly, and then
> git-cherry gets very confused when asked to compare the trunk vs. the
> branches.
> 
> How do we solve it?
> This is only on a conceptual level here, looking at the present state of
> git-svn, I'm not sure how best to solve it.
> 
> git-svn fetch:
> 1. Get commit message from SVN. 
> 2. Trim ALL trailing blank lines (and existing git-svn-id lines).
> 3. If the last line was header-style (Signed-off-by, CC, etc)
> 3.1. if it was, do not add a blank line.
> 3.2. If not, add a single blank line.
> 4. Insert git-svn-id header.

Too much magic.  I don't think this is a good idea, at least
not by default.

> git-svn dcommit:
> 1. Get commit message (git cat-file commit ....)
> 2. Remove the git-svn-id line.
> 3. Remove all trailing blank lines.
> 4. Commit.

We already do step 3.  The problem is that we fail to remove the newline
*before* the git-svn-id line.  I'll make a mental note to fix this
sometime this week, I hope.

-- 
Eric Wong