"Philip Oakley" <philipoak...@iee.org> writes: > If I now understand correctly, the merge process flow is: > > * canonicalise content (eol, smudge-clean, $id, renormalise, etc) > * diff the content (internal, or GIT_EXTERNAL_DIFF) > * apply the diff > * if conflicts, only then use merge-driver/tool > > Would that be a correct interpretation?
Not quite. There are a lot more going on before any of those steps: * Find the common ancestor commit (which could be many). * Walk the three trees (the common ancestor's, ours and theirs) in parallel, noticing what happened to each path. Depending on what happened to the path in each branch, the merge may or may not "conflict" (e.g. when both sides added exactly the same contents to the same path, they are not counted as conflicting. when we removed while they modified, they show as conflicting). * For paths that are conflicting, feed the canonicalized content of the versions from common, ours and theirs to the file-level merge driver. The builtin file-level merge driver takes two xdiff (one between ancestor and ours, the other between ancestore and theirs) and reconciles them to produce the result. But that is irrelevant in the context of "custom merge driver"; the builtin one is skipped altogether and the custom contents merge driver the user specified via the attributes is used instead. Notice that the second step above has no customization knobs. Any path the second step deems not to conflict is "merged cleanly" without even triggering the "oops, ours and theirs did conflicting changes, to the content; let's see how the final content should look like" (aka the third step). This is *not* because "Git knows the best"; it is merely that nobody felt the need for a mechanism to allow customizing the second step. And that is why I said you need a new customization mechanism if you want to affect the outcome of the scenario that started this thread.
