Changes between Version 10 and Version 11 of GitCreateBundle

Timestamp:

Oct 23, 2013, 4:08:16 PM (12 years ago)

Author:

Piero Campalani

Comment:

add section on reverting merges

GitCreateBundle

@@ -232 +232 @@
 ...and now you can proceed with the [wiki:GitCreateBundle#Creatingandsubmittingabundle bundle].
 
+== I don't see any merge commit ==
+
+..you probably either forgot to add the `--no-ff` option when calling the merge (by default, but only if the merge is fast-forward, a normal single-parent commit is created), or somehow your .git/MERGE_HEAD passed away.
+
+This means you have your merge commit with lots of conflicts fixed that you want to re-apply.
+One idea is to:
+
+   * save your merge to a patch, say `MERGE.patch`
+   * reset to a pre-merge state and re-merge
+   * if you have conflicts, just git-add everything to make git think you solved them, then commit
+   * revert the (fake) commit and format a patch out of it, say `REVERT.patch`
+   * reset again to a pre-merge state and again re-merge
+   * re-git-add everything to mark conflicts solved (even though they aren't), but don't commit this time
+   * apply `REVERT.patch` then `MERGE.patch` in the index
+   * the two patches are applied, now you can git-commit.
+
+Let's say you applied a merge `M` of `feature_X` into `master`, but you see no merge commit in your history:
+
+{{{
+  o-------A--------------M  master
+           \            
+            C----------D  feature_X
+}}}
+
+{{{
+#!sh
+# Patch your merge commit:
+$ git branch
+* master
+  feature_X
+$ git format-patch HEAD~
+MERGE.patch
+
+# Re-merge
+$ git reset --hard A
+$ git merge --no-ff feature_X
+...
+Automatic merge failed; fix conflicts and then commit the result.
+
+# Mark conflicts as solved, without applying changes
+$ git add folder1/ folder2/ ...
+$ git commit 
+# let's call it M'
+
+# Revert your fake merge
+$ git revert -m 1 M'
+# let's call this commit rM'
+
+# Patch the reversion
+$ git format-patch HEAD~
+REVERT.patch
+}}}
+
+Graphically, this is the current situation:
+
+{{{
+  o-------A--------------M'----------rM'  master
+           \            /
+            C----------D  feature_X
+}}}
+
+Now we roll-back to a pre-merge state again, then we merge, revert, and apply our initial patch: `(M'+rM'+M) = (M'-M'+M) = M`
+
+{{{
+#!sh
+# Re-merge
+$ git reset --hard A
+$ git merge --no-ff feature_X
+...
+Automatic merge failed; fix conflicts and then commit the result.
+
+# Mark conflicts as solved, without applying changes, but don't commit now
+$ git add folder1/ folder2/ ...
+# ... now we are @ M', without explicit commit
+
+# Apply rM' and M (without commiting)
+$ git apply --index REVERT.patch
+$ git apply --index MERGE.patch
+}}}
+
+Finally, we have our original merge, with true conflicts solution, but as a merge commit:
+
+{{{
+  o-------A--------------M  master
+           \            /
+            C----------D  feature_X
+}}}
+
+
 == Further reading ==
 
@@ -237 +326 @@
    * [http://stackoverflow.com/questions/3635952/how-to-use-git-bundle-for-keeping-development-in-sync How to use git-bundle for keeping development in sync]
    * [http://stackoverflow.com/questions/2285699/git-how-to-create-patches-for-a-merge Git: How to create patches for a merge?]
+   * [http://git-scm.com/2010/03/02/undoing-merges.html Undoing Merges]