# Re: [Q] merge squash unexpected conflicts 11 messages from 2009-05-14 to 2009-05-14. Participants: Cory Sharp, Junio C Hamano, Michael Radziej, Michael J Gruber. Thread: https://gitlist.dev/t/19342 ## Cory Sharp, 2009-05-14 02:42 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: URL: https://gitlist.dev/e/bb9d69200905131942t7a43a29fh9638d2548e9f12dc%40mail.gmail.com In-Reply-To: ``` Using git 1.6.3.1, when using "git merge --squash" I get unexpected conflicts when merging an update to a file that was added after the original branch point, like this   * Initialize git repo   * Add hello to master   * Create topic branch   * Add goodbye to master   * Merge squash master into topic, gets new goodbye   * Update goodbye in master   * Again merge squash master into topic, update goodbye The second merge squash produces a conflict in goodbye. Am I doing something a little wrong or unexpected?  Is there a way around this squash conflict behavior?  This doesn't seem to happen with plain merge without squash. I've appended a small bash script to show this behavior - run it from an empty directory. Thanks, Cory #!/bin/sh try() {     echo "$@"     "$@" || exit 1 } note() {     echo     echo "##" "$@" "##" } [ -d .git ] && echo .git already exists, aborting. && exit 1 note "Initialize git repo" try git init note "Add hello to master" echo "hello world" > hello.txt try git add hello.txt try git commit -m "Added hello" note "Create topic branch" try git checkout -b topic note "Add goodbye to master" try git checkout master echo "farewell world" > goodbye.txt try git add goodbye.txt try git commit -m "Added goodbye" note "Merge master into topic, gets new goodbye" try git checkout topic try git merge --squash master try git commit -m "Merged master" note "Update goodbye in master" try git checkout master echo "goodbye world" > goodbye.txt try git add goodbye.txt try git commit -m "Updated goodbye" note "Again merge master into topic, update goodbye" try git checkout topic try git merge --squash master ``` ## Junio C Hamano, 2009-05-14 03:21 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: <7v4ovo1iap.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7v4ovo1iap.fsf%40alter.siamese.dyndns.org In-Reply-To: ``` Cory Sharp writes: > Am I doing something a little wrong or unexpected?  Is there a way > around this squash conflict behavior?  This doesn't seem to happen > with plain merge without squash. Of course. That's the whole point of recording a merge as a merge. ``` ## Cory Sharp, 2009-05-14 03:57 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: URL: https://gitlist.dev/e/bb9d69200905132057u60adc2f8vb9ba9a35791f72ac%40mail.gmail.com In-Reply-To: <7v4ovo1iap.fsf@alter.siamese.dyndns.org> ``` On Wed, May 13, 2009 at 8:21 PM, Junio C Hamano wrote: > Cory Sharp writes: > >> Am I doing something a little wrong or unexpected?  Is there a way >> around this squash conflict behavior?  This doesn't seem to happen >> with plain merge without squash. > > Of course.  That's the whole point of recording a merge as a merge. > $ git help merge --squash Produce the working tree and index state as if a real merge happened. ... This allows you to create a single commit on top of the current branch whose effect is the same as merging another branch. ``` ## Junio C Hamano, 2009-05-14 04:42 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: <7veiusz45w.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7veiusz45w.fsf%40alter.siamese.dyndns.org In-Reply-To: ``` Cory Sharp writes: > On Wed, May 13, 2009 at 8:21 PM, Junio C Hamano wrote: > .. >> Of course. That's the whole point of recording a merge as a merge. >> > > $ git help merge > > --squash > Produce the working tree and index state as if a real merge > happened. ... This allows you to create a > single commit on top of the current branch whose effect is > the same as merging another branch. What's your point? WIth --squash, the tree and the index state becomes the same as if a real merge happened. But the merge history is discarded with --squash. It is a simulation of a merge in CVS and SVN (before they added "merge tracking"). If you want support for repeated merges by merge tracking, you do not want todiscard the merge history by using --squash. ``` ## Cory Sharp, 2009-05-14 06:34 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: URL: https://gitlist.dev/e/bb9d69200905132334m7a4e3a4akde3529abeab5a09%40mail.gmail.com In-Reply-To: <7veiusz45w.fsf@alter.siamese.dyndns.org> ``` On Wed, May 13, 2009 at 9:42 PM, Junio C Hamano wrote: > What's your point? I am asking for help and understanding. > WIth --squash, the tree and the index state becomes the same as if a real > merge happened.  But the merge history is discarded with --squash.  It is > a simulation of a merge in CVS and SVN (before they added "merge tracking"). > > If you want support for repeated merges by merge tracking, you do not want > todiscard the merge history by using --squash. Why doesn't --squash do merge tracking? The help didn't indicate that it doesn't, and I don't understand why it shouldn't -- since I *could* track the previous merge point manually and do "git diff --binary PREV_MERGE..NEXT_MERGE | git apply -" to do the merge myself. But since that's me manually performing merge tracking, why doesn't "merge --squash" track like just "merge" does? If I didn't want tracking, I would expect to use some other command than "git merge [options]". Thanks for your help, Cory ``` ## Junio C Hamano, 2009-05-14 06:42 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: <7v4ovoxk0n.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7v4ovoxk0n.fsf%40alter.siamese.dyndns.org In-Reply-To: ``` Cory Sharp writes: >> If you want support for repeated merges by merge tracking, you do not want >> todiscard the merge history by using --squash. > > Why doesn't --squash do merge tracking? The help didn't indicate that > it doesn't, and I don't understand why ... Because "merge" is (no surprise) what tracks what (two or more) things were merged. And with --squash you are choosing not to make a merge. I am not sure if there is any more thing to be explained... ``` ## Cory Sharp, 2009-05-14 06:54 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: URL: https://gitlist.dev/e/bb9d69200905132354h6b64171g24351840fb1d0893%40mail.gmail.com In-Reply-To: <7v4ovoxk0n.fsf@alter.siamese.dyndns.org> ``` On Wed, May 13, 2009 at 11:42 PM, Junio C Hamano wrote: > Because "merge" is (no surprise) what tracks what (two or more) things > were merged.  And with --squash you are choosing not to make a merge.  I > am not sure if there is any more thing to be explained... Yeah I'm not quite getting it. Thanks for trying to explain, though. ``` ## Michael Radziej, 2009-05-14 07:01 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: <20090514070129.GL8212@noris.de> URL: https://gitlist.dev/e/20090514070129.GL8212%40noris.de In-Reply-To: ``` On Wed, May 13, Cory Sharp wrote: > Yeah I'm not quite getting it. Thanks for trying to explain, though. git merge --squash is not a merge at all. It only creates a regular commit with one parent. It is useful only in very special circumstances. Michael -- noris network AG - Deutschherrnstraße 15-19 - D-90429 Nürnberg - Tel +49-911-9352-0 - Fax +49-911-9352-100 http://www.noris.de - The IT-Outsourcing Company Vorstand: Ingo Kraupa (Vorsitzender), Joachim Astel, Hansjochen Klenk - Vorsitzender des Aufsichtsrats: Stefan Schnabel - AG Nürnberg HRB 17689 ``` ## Michael J Gruber, 2009-05-14 12:17 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: <4A0C0BDF.9020803@drmicha.warpmail.net> URL: https://gitlist.dev/e/4A0C0BDF.9020803%40drmicha.warpmail.net In-Reply-To: ``` Cory Sharp venit, vidit, dixit 14.05.2009 05:57: > On Wed, May 13, 2009 at 8:21 PM, Junio C Hamano wrote: >> Cory Sharp writes: >> >>> Am I doing something a little wrong or unexpected? Is there a way >>> around this squash conflict behavior? This doesn't seem to happen >>> with plain merge without squash. >> >> Of course. That's the whole point of recording a merge as a merge. >> > > $ git help merge > > --squash > Produce the working tree and index state as if a real merge > happened. ... This allows you to create a > single commit on top of the current branch whose effect is > the same as merging another branch. The problem is simply in the "...". You cut out the vital part: but do not actually make a commit or move the `HEAD`, nor record `$GIT_DIR/MERGE_HEAD` to cause the next `git commit` command to create a merge commit. See? Tree: yes, index: yes, merge info: no. Git does perform a (tree) merge with --squash, but records the resulting tree as an ordinary non-merge commit (with a single parent). I'm not sure whether the statement about the index is completely correct, though. During a merge the index records info about the merge (stages :1: etc.) but that as missing with --squash. Only the resulting tree is added to the index. How about the below? Michael diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt index 637b53f..adadf8e 100644 --- a/Documentation/merge-options.txt +++ b/Documentation/merge-options.txt @@ -39,7 +39,8 @@ --squash:: Produce the working tree and index state as if a real - merge happened, but do not actually make a commit or + merge happened (except for the merge information), + but do not actually make a commit or move the `HEAD`, nor record `$GIT_DIR/MERGE_HEAD` to cause the next `git commit` command to create a merge commit. This allows you to create a single commit on ``` ## Cory Sharp, 2009-05-14 14:47 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: URL: https://gitlist.dev/e/bb9d69200905140747j60b2e09flaabbb4db09b371b4%40mail.gmail.com In-Reply-To: <4A0C0BDF.9020803@drmicha.warpmail.net> ``` On Thu, May 14, 2009 at 5:17 AM, Michael J Gruber wrote: > Cory Sharp venit, vidit, dixit 14.05.2009 05:57: >> On Wed, May 13, 2009 at 8:21 PM, Junio C Hamano wrote: >>> Cory Sharp writes: >>> >>>> Am I doing something a little wrong or unexpected?  Is there a way >>>> around this squash conflict behavior?  This doesn't seem to happen >>>> with plain merge without squash. >>> >>> Of course.  That's the whole point of recording a merge as a merge. >>> >> >> $ git help merge >> >>   --squash >>            Produce the working tree and index state as if a real merge >> happened. ... This allows you to create a >>            single commit on top of the current branch whose effect is >> the same as merging another branch. > > The problem is simply in the "...". You cut out the vital part: > > >        but do not actually make a commit or >        move the `HEAD`, nor record `$GIT_DIR/MERGE_HEAD` to >        cause the next `git commit` command to create a merge >        commit. > > See? Tree: yes, index: yes, merge info: no. > > Git does perform a (tree) merge with --squash, but records the resulting > tree as an ordinary non-merge commit (with a single parent). > > I'm not sure whether the statement about the index is completely > correct, though. During a merge the index records info about the merge > (stages :1: etc.) but that as missing with --squash. Only the resulting > tree is added to the index. How about the below? Now I see, thanks for the help. The elided part, at the time I elided it, did not make me understand that merge info was not written, particularly when surrounded by its original accompanying text. Thanks again, Cory ``` ## Cory Sharp, 2009-05-14 18:25 Subject: Re: [Q] merge squash unexpected conflicts Message-ID: URL: https://gitlist.dev/e/bb9d69200905141125i4a8ffaa8j6aea2a6c44de0c7d%40mail.gmail.com In-Reply-To: <20090514070129.GL8212@noris.de> ``` On Thu, May 14, 2009 at 12:01 AM, Michael Radziej wrote: > git merge --squash is not a merge at all. ... > It is useful only in very special circumstances. You're right. I (incorrectly) thought I had to use --squash to properly interface with an svn branch and trunk through git-svn. I thought not using squash would trigger hundreds of commits - it doesn't, nice things happen with just "merge". Thanks everyone for helping me, Cory ```