Git Merge Tree Exit Status, Usage, and Input Format

section starts with a blank line to separate it from the previous sections, and then only contains the <conflict-message> information from the previous section (separated by newlines). These are non-stable strings that should not be parsed by scripts, and are just meant for human consumption. Also, note that while <conflict-message> strings usually do not contain embedded newlines, they sometimes do. (However, the free-form messages will never have an embedded NUL character). So, the entire block of information is meant for human readers as an agglomeration of all conflict messages. EXIT STATUS ----------- For a successful, non-conflicted merge, the exit status is 0. When the merge has conflicts, the exit status is 1. If the merge is not able to complete (or start) due to some kind of error, the exit status is something other than 0 or 1 (and the output is unspecified). When --stdin is passed, the return status is 0 for both successful and conflicted merges, and something other than 0 or 1 if it cannot complete all the requested merges. USAGE NOTES ----------- This command is intended as low-level plumbing, similar to linkgit:git-hash-object[1], linkgit:git-mktree[1], linkgit:git-commit-tree[1], linkgit:git-write-tree[1], linkgit:git-update-ref[1], and linkgit:git-mktag[1]. Thus, it can be used as a part of a series of steps such as: vi message.txt BRANCH1=refs/heads/test BRANCH2=main NEWTREE=$(git merge-tree --write-tree $BRANCH1 $BRANCH2) || { echo "There were conflicts..." 1>&2 exit 1 } NEWCOMMIT=$(git commit-tree $NEWTREE -F message.txt \ -p $BRANCH1 -p $BRANCH2) git update-ref $BRANCH1 $NEWCOMMIT Note that when the exit status is non-zero, `NEWTREE` in this sequence will contain a lot more output than just a tree. For conflicts, the output includes the same information that you'd get with linkgit:git-merge[1]: * what would be written to the working tree (the <<OIDTLT,OID of toplevel tree>>) * the higher order stages that would be written to the index (the <<CFI,Conflicted file info>>) * any messages that would have been printed to stdout (the <<IM,Informational messages>>) [[INPUT]] INPUT FORMAT ------------ 'git merge-tree --stdin' input format is fully text based. Each line has this format: [<base-commit> -- ]<branch1> <branch2> If one line is separated by `--`, the string before the separator is used for specifying a merge-base for the merge and the string after the separator describes the branches to be merged. MISTAKES TO AVOID ----------------- Do NOT look through the resulting toplevel tree to try to find which files conflict; parse the <<CFI,Conflicted file info>> section instead. Not only would parsing an entire tree be horrendously slow in large repositories, there are numerous types of conflicts not representable by conflict markers (modify/delete, mode conflict, binary file changed on both sides, file/directory conflicts, various rename conflict permutations, etc.) Do NOT interpret an empty <<CFI,Conflicted file info>> list as a clean merge; check the exit status. A merge can have conflicts without having individual files conflict (there are a few types of directory rename conflicts that fall into this category, and

The git merge-tree command returns an exit status indicating success, conflict, or error, and its usage is demonstrated in a series of steps for performing a merge, and the input format for --stdin is described, along with warnings on how to correctly interpret the output and avoid common mistakes.