# git log history simplification problem 5 messages from 2014-02-04 to 2014-02-04. Participants: Miklos Vajna, Jonathan Nieder, Junio C Hamano. Thread: https://gitlist.dev/t/35796 ## Miklos Vajna, 2014-02-04 17:37 Subject: git log history simplification problem Message-ID: <20140204173713.GC17861@collabora.co.uk> URL: https://gitlist.dev/e/20140204173713.GC17861%40collabora.co.uk ``` Hi, I was trying to understand the history of a piece of code in LibreOffice and I'm facing a behaviour of git-log which is not something I can explain. I'm not sure if this is a git bug or a user error. ;) Here is the situation: git clone git://anongit.freedesktop.org/libreoffice/core cd core git log --full-history -p -S'mnTitleBarHeight =' sd/source/ui/dlg/PaneDockingWindow.cxx Here the first output I get from git-log is b390fae1706b9c511158a03e4fd61f263be4e511, where you can see that the commit *added* that string. So it should be there on master, I would assume. But then I run: git grep 'mnTitleBarHeight =' sd and it's not there. Am I missing something, as in e.g. even with --full-history git-log does some simplification? Thanks, Miklos ``` ## Miklos Vajna, 2014-02-04 19:05 Subject: Re: git log history simplification problem Message-ID: <20140204190516.GD17861@collabora.co.uk> URL: https://gitlist.dev/e/20140204190516.GD17861%40collabora.co.uk In-Reply-To: <20140204173713.GC17861@collabora.co.uk> ``` On Tue, Feb 04, 2014 at 06:37:13PM +0100, Miklos Vajna wrote: > But then I run: > > git grep 'mnTitleBarHeight =' sd > > and it's not there. Am I missing something, as in e.g. even with > --full-history git-log does some simplification? I tried to reproduce this with a repo from scratch, and it seems my problem is the following: 1) "A" creates a feature branch 2) "A" works on it, and in the meantime master progresses as well 3) "A" merges master to the feature branch 4) "A" does some additional changes, and -- in an evil way -- uses "git commit -a --amend" to squeeze these into the merge commit 5) "B" (that's me) comes and try to find out where a string got deleted, but can't. Here is a reproducer script: ---- rm -rf scratch mkdir scratch cd scratch git init echo -e "a\na\na\na\na\na\na\na\n" > a git add a git commit -m init git branch feature echo "b" >> a git add a git commit -m "more master changes" git checkout feature sed -i '1iXXX' a # insert first row git add a git commit -m "feature" git merge -m merge master sed -i '1d' a # delete first row git add a git commit --amend -m "merge" ---- I now know that the XXX got removed by the merge commit, but how can I see it that I'm right? If I run 'git log --all -p' in the result, I see that XXX got inserted by one commit, now I don't have it, but I don't see any deletion, which confuses me. Any ideas? :-) Thanks, Miklos ``` ## Jonathan Nieder, 2014-02-04 19:48 Subject: Re: git log history simplification problem Message-ID: <20140204194842.GM30398@google.com> URL: https://gitlist.dev/e/20140204194842.GM30398%40google.com In-Reply-To: <20140204173713.GC17861@collabora.co.uk> ``` Hi, Miklos Vajna wrote: > git clone git://anongit.freedesktop.org/libreoffice/core > cd core > git log --full-history -p -S'mnTitleBarHeight =' sd/source/ui/dlg/PaneDockingWindow.cxx > > Here the first output I get from git-log is > b390fae1706b9c511158a03e4fd61f263be4e511, where you can see that the > commit *added* that string. So it should be there on master, I would > assume. df76bfb0695d19d201936df80192108e7ce51b8c (a merge) removed it. Plain 'git log' doesn't notice because in the default mode it skips merges. Since the culprit commit is not in the first-parent history of HEAD, my usual approach doesn't help, either: $ git log -m --first-parent -S'mnTitleBarHeight =' \ -- sd/source/ui/dlg/PaneDockingWindow.cxx $ Using -c or --cc produces too many hits. Luckily '-m -p' without --first-parent worked and the first commit it showed was the right one. It produces more hits than I'd like, too, though. The -L option doesn't interact well enough with --reverse to handle this case: $ git grep -p -e'mnTitleBarHeight =' b390fae1 -- sd/source/ui/dlg/PaneDockingWindow.cxx b390fae1:sd/source/ui/dlg/PaneDockingWindow.cxx=void PaneDockingWindow::Layout (void) b390fae1:sd/source/ui/dlg/PaneDockingWindow.cxx: mnTitleBarHeight = GetSettings().GetStyleSettings().GetTitleHeight(); b390fae1:sd/source/ui/dlg/PaneDockingWindow.cxx: mnTitleBarHeight = aToolBoxSize.Height(); b390fae1:sd/source/ui/dlg/PaneDockingWindow.cxx: mnTitleBarHeight = aToolBoxSize.Height(); $ git log --reverse b390fae1..HEAD \ -L:Layout:sd/source/ui/dlg/PaneDockingWindow.cxx fatal: -L parameter 'Layout' starting at line 1: no match Thanks for a useful example. Jonathan ``` ## Miklos Vajna, 2014-02-04 20:07 Subject: Re: git log history simplification problem Message-ID: <20140204200703.GE17861@collabora.co.uk> URL: https://gitlist.dev/e/20140204200703.GE17861%40collabora.co.uk In-Reply-To: <20140204194842.GM30398@google.com> ``` Hi Jonathan, On Tue, Feb 04, 2014 at 11:48:42AM -0800, Jonathan Nieder wrote: > Luckily '-m -p' without --first-parent worked and the first commit it > showed was the right one. It produces more hits than I'd like, too, > though. Ah, excellent! :-) '-m' does what I need. Thanks a lot, Miklos ``` ## Junio C Hamano, 2014-02-04 20:11 Subject: Re: git log history simplification problem Message-ID: URL: https://gitlist.dev/e/xmqqiosu8wpv.fsf%40gitster.dls.corp.google.com In-Reply-To: <20140204173713.GC17861@collabora.co.uk> ``` Miklos Vajna writes: > Hi, > > I was trying to understand the history of a piece of code in LibreOffice > and I'm facing a behaviour of git-log which is not something I can > explain. I'm not sure if this is a git bug or a user error. ;) > > Here is the situation: > > git clone git://anongit.freedesktop.org/libreoffice/core > cd core > git log --full-history -p -S'mnTitleBarHeight =' sd/source/ui/dlg/PaneDockingWindow.cxx Lack of -m is what I would first suspect when somebody misunderstands "merge simplification". I am not saying that will be the issue, but merely pointing out that that is the first thing that jumps at me when I view the above command line. > > Here the first output I get from git-log is > b390fae1706b9c511158a03e4fd61f263be4e511, where you can see that the > commit *added* that string. So it should be there on master, I would > assume. > > But then I run: > > git grep 'mnTitleBarHeight =' sd > > and it's not there. Am I missing something, as in e.g. even with > --full-history git-log does some simplification? > > Thanks, > > Miklos ```