Can changes be conflictless overwritten when using git merge with recursive strategy?

Question

I am managing the source code of a project in my company with Git (GitLab) to be precise. Two developers work on the project, create a branch for every task then create a merge request. I mostly merge these directly via the UI which should be the same as doing this in the command line:

git checkout master
git merge --no-ff 1224-cool-feature-branch

From time to time I have seen small features or parts of pages disappear.

Consider the following case

• Dev A branches from master at ab12 -> new branchname FeatureA
• Dev B branches from master at ab12 -> new branchname FeatureB
• Dev A changes foobar.txt and commits to FeatureA
• FeatureA is merged into master using merge --no-ff using the default recursive strategy
• Dev B changes foobar.txt and commits to Feature B
• FeatureB is merged into master using merge --no-ff using the default recursive strategy without conflict

Is it possible that changes to foobar.txt from FeatureAhave been overwritten without creating a conflict?

Answer 1

I believe the answer is "no". The file is merged using the conventional 3 way merge which should apply change if they are distant enough from each other or report a conflict, there is no other option.

There could be some issues with this approach, see for example http://r6.ca/blog/20110416T204742Z.html , but I cannot imagine how any corner case would result in silent edit reversal.