Git merge using recursive strategy and patience option

Question

How to merge a branch with git using patience option provided by the recursive strategy? I\'m using git version 1.7.3.1.msysgit.0

Even docs are not consistent and, what\

Answer 1

I see here the patch introducing the patience option to the recursive merge strategy, base on Git1.7.2.2, but I don't see it in any of the subsequent release notes.

Yet the patience diff algorithm has been presented since 2009, and is detailed here.

> grep -i patience *.c
diff.c: else if (!strcmp(arg, "--patience"))
diff.c:         DIFF_XDL_SET(options, PATIENCE_DIFF);
merge-recursive.c:      else if (!strcmp(s, "patience"))
merge-recursive.c:              o->xdl_opts |= XDF_PATIENCE_DIFF;

The merge command should understand this option... but this function below seems to never be called (not anywhere in merge-recursive.c or in any other *.c file!):

int parse_merge_opt(struct merge_options *o, const char *s)
{
    if (!s || !*s)
        return -1;
    if (!strcmp(s, "ours"))
        o->recursive_variant = MERGE_RECURSIVE_OURS;
    else if (!strcmp(s, "theirs"))
        o->recursive_variant = MERGE_RECURSIVE_THEIRS;
    else if (!strcmp(s, "subtree"))
        o->subtree_shift = "";
    else if (!prefixcmp(s, "subtree="))
        o->subtree_shift = s + strlen("subtree=");
    else if (!strcmp(s, "patience"))
        o->xdl_opts |= XDF_PATIENCE_DIFF;
    else if (!strcmp(s, "ignore-space-change"))
        o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
    else if (!strcmp(s, "ignore-all-space"))
        o->xdl_opts |= XDF_IGNORE_WHITESPACE;
    else if (!strcmp(s, "ignore-space-at-eol"))
        o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
    else if (!strcmp(s, "renormalize"))
        o->renormalize = 1;
    else if (!strcmp(s, "no-renormalize"))
        o->renormalize = 0;
    else if (!prefixcmp(s, "rename-threshold=")) {
        const char *score = s + strlen("rename-threshold=");
        if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
            return -1;
    }
    else
        return -1;
    return 0;
}

The "Unknown option" error message is only printed by the handle_options function in git.c.
And XDF_PATIENCE_DIFF doesn't show anywhere else in git sources (1.7.4)... so yes, I don't know how this could be implemented for the merge.

Answer 2

The --patience option for git merge-recursive was introduced in commit 58a1ece478c6038a7eb0b6e494d563bd5e6d5978. You can find out in a clone of git.git what versions contain this change with git tag --contains 58a1ece478:

v1.7.4
v1.7.4-rc0
v1.7.4-rc1
v1.7.4-rc2
v1.7.4-rc3
v1.7.4.1

So I suspect that you're just using a slightly too old version of mSysGit. There is a preview version of 1.7.4 available now - I think you should try that one.

I've just tried this with git version 1.7.4, and the following command line syntax works for me:

git merge -s recursive -X patience other-branch