read-tree --aggressive

A new flag --aggressive resolves what we traditionally resolved
with external git-merge-one-file inside index while read-tree
3-way merge works.

git-merge-octopus and git-merge-resolve use this flag before
running git-merge-index with git-merge-one-file.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-merge-octopus.sh b/git-merge-octopus.sh
index eb74f96..eb3f473 100755 (executable)
--- a/git-merge-octopus.sh
+++ b/git-merge-octopus.sh
@@ -90,7 +90,7 @@ do
        NON_FF_MERGE=1
 
        echo "Trying simple merge with $SHA1"
-       git-read-tree -u -m $common $MRT $SHA1 || exit 2
+       git-read-tree -u -m --aggressive  $common $MRT $SHA1 || exit 2
        next=$(git-write-tree 2>/dev/null)
        if test $? -ne 0
        then

diff --git a/git-merge-resolve.sh b/git-merge-resolve.sh
index 966e81f..0a8ef21 100755 (executable)
--- a/git-merge-resolve.sh
+++ b/git-merge-resolve.sh
@@ -38,7 +38,7 @@ then
 fi
 
 git-update-index --refresh 2>/dev/null
-git-read-tree -u -m $bases $head $remotes || exit 2
+git-read-tree -u -m --aggressive $bases $head $remotes || exit 2
 echo "Trying simple merge."
 if result_tree=$(git-write-tree  2>/dev/null)
 then

diff --git a/read-tree.c b/read-tree.c
index a46c6fe..5580f15 100644 (file)
--- a/read-tree.c
+++ b/read-tree.c
@@ -15,6 +15,7 @@ static int update = 0;
 static int index_only = 0;
 static int nontrivial_merge = 0;
 static int trivial_merges_only = 0;
+static int aggressive = 0;
 
 static int head_idx = -1;
 static int merge_size = 0;
@@ -424,11 +425,14 @@ static int threeway_merge(struct cache_entry **stages)
        int df_conflict_remote = 0;
 
        int any_anc_missing = 0;
+       int no_anc_exists = 1;
        int i;
 
        for (i = 1; i < head_idx; i++) {
                if (!stages[i])
                        any_anc_missing = 1;
+               else
+                       no_anc_exists = 0;
        }
 
        index = stages[0];
@@ -489,6 +493,29 @@ static int threeway_merge(struct cache_entry **stages)
        if (!head && !remote && any_anc_missing)
                return 0;
 
+       /* Under the new "aggressive" rule, we resolve mostly trivial
+        * cases that we historically had git-merge-one-file resolve.
+        */
+       if (aggressive) {
+               int head_deleted = !head && !df_conflict_head;
+               int remote_deleted = !remote && !df_conflict_remote;
+               /*
+                * Deleted in both.
+                * Deleted in one and unchanged in the other.
+                */
+               if ((head_deleted && remote_deleted) ||
+                   (head_deleted && remote && remote_match) ||
+                   (remote_deleted && head && head_match))
+                       return 0;
+
+               /*
+                * Added in both, identically.
+                */
+               if (no_anc_exists && head && remote && same(head, remote))
+                       return merged_entry(head, index);
+
+       }
+
        /* Below are "no merge" cases, which require that the index be
         * up-to-date to avoid the files getting overwritten with
         * conflict resolution files. 
@@ -677,6 +704,11 @@ int main(int argc, char **argv)
                        continue;
                }
 
+               if (!strcmp(arg, "--aggressive")) {
+                       aggressive = 1;
+                       continue;
+               }
+
                /* "-m" stands for "merge", meaning we start in stage 1 */
                if (!strcmp(arg, "-m")) {
                        if (stage || merge)