On Wed, Sep 17, 2014 at 05:52:29AM -0700, Dmitry Moscow wrote: > > > I come from an SVN background, and I have a hard time grasping Git's > philosophy. In particular, I'm confused by the following. > > 1. Imagine I have made some changes in my working dir. If I switch > to another branch, the changes*remain*, which is very unusual, > from an SVN point of view. This means that uncommitted changes > are*shared* between the branches. Moreover, the "stage property" > of the files is also *shared* between the branches: if I call > git add * in one branch, then all the files will be added to > next commit in all the branches. Looks like my branches differ > only by already *committed* files.
Actually, SVN behaves the same way in regards to jumping between branches with changes present: ~~~ % svn info|grep Relative Relative URL: ^/trunk % svn st M bar % svn diff Index: bar =================================================================== --- bar (revision 3) +++ bar (working copy) @@ -0,0 +1 @@ +Hello. % svn switch ^/branches/b1 At revision 3. % svn diff Index: bar =================================================================== --- bar (revision 3) +++ bar (working copy) @@ -0,0 +1 @@ +Hello. ~~~ And keep in mind that SVN only has an explicit staging step when adding files. Furthermore, the staging area in git is not tied to a branch, it's tied to the working area. Again, just as in SVN. > So, if uncommitted data are *shared*, then, no matter which branch I am > on now, I will commit *all the staged files*, even if they were added in > different branches! As I come from an SVN background, this strikes me as > very odd. Also for files that are just added does SVN behave exactly the same as git. ~~~ % svn info|grep Relative Relative URL: ^/trunk % touch qux % svn add qux A qux % svn switch ^/branches/b1 At revision 3. % svn st A qux ~~~ > Am I correct, or am I just confused? Why does Git work in this way? So, if I understand you correctly you actually are confused ;) No seriously, of course it's a valid question to ask 'why'. Interesting though that you never ran into the behaviour when using SVN. > 2. Sometimes, Git tells me something like this: > > Cannot switch to another branch because your changes will be > erased. Commit them first. > > In SVN, that's not a problem: branches are *independent*. Why and > when does this happen in Git? It happens at the same point as when you get a merge conflict in SVN ;) ~~~ % svn info|grep Relative Relative URL: ^/trunk % svn cat ^/trunk/bar % svn cat ^/branches/b1/bar foo bar % echo 'wibble wobble' >> bar % svn st M bar % svn switch ^/branches/b1 C bar Updated to revision 4. Conflict discovered in file 'bar'. Select: (p) postpone, (df) show diff, (e) edit file, (m) merge, (mc) my side of conflict, (tc) their side of conflict, (s) show all options: ~~~ That is, git tells you it can't switch to the other branch without losing your changes. Just as SVN does. They just do it in different ways; SVN forces you to merge, git forces you to remove the changes or commit them first. /M -- Magnus Therning OpenPGP: 0xAB4DFBA4 email: mag...@therning.org jabber: mag...@therning.org twitter: magthe http://therning.org/magnus Any fool can write code that a computer can understand. Good programmers write code that humans can understand. -- Martin Fowler
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