From 7dd31f64a4f57a2db2a504b026dbab7cde2b84bc Mon Sep 17 00:00:00 2001
From: Malf Furious <m@lfurio.us>
Date: Wed, 6 Sep 2017 00:37:26 -0400
Subject: Add merge op

---
 merge.sh | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 178 insertions(+)
 create mode 100644 merge.sh

diff --git a/merge.sh b/merge.sh
new file mode 100644
index 0000000..071ddca
--- /dev/null
+++ b/merge.sh
@@ -0,0 +1,178 @@
+##
+# systr_merge_tree <commit>
+#
+# Merge the contents of <commit> into the current worktree, using
+# the calculated merge-base of <commit> and BASE (since your worktree
+# is essentally BASE plus pending changes).
+#
+# The merge is staged in a separate directory.  This is because systrunk
+# doesn't want to overwrite the worktree unless the merge will run
+# successfully.  We don't want to write garbage to the worktree and lose
+# uncommitted changes to other files.  Users can resolve conflicts in
+# this separate tree and either apply the complete merge when ready;
+# or abort the merge alltogether, if problems arise.
+#
+# Invoke systr_merge_finish to apply new content to the worktree and
+# prep for a merge-commit.
+##
+function systr_merge_tree
+{
+    if [ $# -lt 1 ]; then
+        echo "Fatal: too few args to merge_tree" >&2
+        exit 1
+    fi
+
+    commit=$(systr_repo_resolve_reference "$1")
+    mergebase=$(systr_repo_merge_base "$commit" "$BASE")
+
+    mergebase=$(
+        cd "$path/revs/$mergebase/"
+        echo $PWD
+    )
+
+    rm -rf .systr/merge/ .systr/tmp/
+    mkdir .systr/merge .systr/tmp
+
+    systr_rsync_diff "$path/revs/$commit/" "$mergebase" .systr/tmp/
+    systr_rsync_diff . "$mergebase" .systr/merge/
+
+    systr_rsync_del "$path/revs/$commit/" "$mergebase" .systr/merge/
+    systr_rsync_del . "$mergebase" .systr/tmp/
+
+    systr_rsync_merge .systr/tmp/ .systr/merge/
+}
+
+##
+# systr_merge_finish <commit>
+#
+# Apply merged contents to the worktree.  This works by first deleted
+# removed files from <commit> then copying the local merge directory
+# into the worktree.
+#
+# Once this completes, the user should run systrunk commit to record
+# the merged tree in the repository.
+##
+function systr_merge_finish
+{
+    if [ $# -lt 1 ]; then
+        echo "Fatal: too few args to merge_finish" >&2
+        exit 1
+    fi
+
+    commit=$(systr_repo_resolve_reference "$1")
+    mergebase=$(systr_repo_merge_base "$commit" "$BASE")
+
+    mergebase=$(
+        cd "$path/revs/$mergebase/"
+        echo $PWD
+    )
+
+    rsync -az --existing --ignore-existing --delete --compare-dest="$mergebase" \
+        --exclude='*.systr' "$path/revs/$commit/" .
+
+    rsync -azi .systr/merge/ .
+
+    rm -rf .systr/merge/ .systr/tmp/
+}
+
+##
+# systrunk merge <commit>
+#
+# Merge the tree of <commit> into the worktree.  If conflicts are found,
+# they are interactively addressed.  Once all conflicts are resolved,
+# the merged content is moved into the worktree, ready for commit.
+# Otherwise, the user may abort the merge, leaving the worktree intact.
+#
+# If <commit>=TRAC, as is the case for an 'update' operation, a merge
+# commit is not expected and the MERG pointer will be cleared after
+# the worktree is successfully updated.
+#
+# If the interactive prompt is left, user can invoke 'systrunk apply-merge'
+# to proceed or 'systrunk abort-merge' to abort.
+##
+function systr_merge
+{
+    if [ $# -lt 1 ]; then
+        echo "Fatal: too few args to merge" >&2
+        exit 1
+    fi
+
+    commit="$1"
+
+    systr_merge_tree "$commit"
+    echo "$commit" >.systr/MERG
+
+    # resolve conflicts #
+    find .systr/merge/ -name '*\*' | while read file;
+    do
+        orig=${file::-1}
+        vimdiff "$orig" "$file"
+        rm "$file"
+    done
+
+    find .systr/merge/ -name '*~' | while read file;
+    do
+        name=${file::-1}
+        echo "$name removed on $commit // {created on worktree}"
+        while true;
+        do
+            echo "Use [d]eleted file     Use [e]dited file     Inspect in [v]im     [A]bort"
+            read opt
+
+            if [[ "$opt" == "d" ]]; then
+                rm "$file"
+                break
+            elif [[ "$opt" == "e" ]]; then
+                mv "$file" "$name"
+                break
+            elif [[ "$opt" == "v" ]]; then
+                vim "$file"
+            elif [[ "$opt" == "A" ]]; then
+                exit
+            fi
+        done
+    done
+
+    find .systr/merge/ -name '*\&' | while read file;
+    do
+        name=${file::-1}
+        echo "$name removed on worktree // {created on $commit}"
+        while true;
+        do
+            echo "Use [d]eleted file     Use [e]dited file     Inspect in [v]im     [A]bort"
+            read opt
+
+            if [[ "$opt" == "d" ]]; then
+                rm "$file"
+                break
+            elif [[ "$opt" == "e" ]]; then
+                mv "$file" "$name"
+                break
+            elif [[ "$opt" == "v" ]]; then
+                vim "$file"
+            elif [[ "$opt" == "A" ]]; then
+                exit
+            fi
+        done
+    done
+
+    # apply merge #
+    systr_merge_finish "$commit"
+
+    if [[ "$commit" == "TRAC" ]]; then
+        echo "NULL" >.systr/MERG
+    fi
+}
+
+##
+# systrunk abort-merge
+#
+# Abort an in-progress merge that has *not* yet been incorporated
+# into the worktree.  This purges the merge staging directories and
+# clears the MERG pointer.
+##
+function systr_merge_abort
+{
+    rm -rf .systr/merge/ .systr/tmp/
+    echo "NULL" >.systr/MERG
+}
-- 
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