@matheusbsbs / matheus-bagliano / commits / 79bc4ef368

filter-branch: eliminate duplicate mapped parents

When multiple parents of a merge commit get mapped to the same commit, filter-branch used to pass all instances of the parent commit to the parent and commit filters and to "git commit-tree" or "git_commit_non_empty_tree". This can often happen when extracting a small project from a large repository; merges can join history with no commits on any branch which affect the paths being retained. Once the intermediate commits have been filtered out, all the immediate parents of the merge commit can end up being mapped to the same commit - either the original merge-base or an ancestor of it. "git commit-tree" would display an error but write the commit with the normalized parents in any case. "git_commit_non_empty_tree" would fail to notice that the commit being made was in fact a non-merge commit and would retain it even if a further pass with "--prune-empty" would discard the commit as empty. Ensure that duplicate parents are pruned before the parent filter to make "--prune-empty" idempotent, removing all empty non-merge commits in a singe pass. Signed-off-by: Charles Bailey <cbailey32@bloomberg.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Charles Bailey committed Jun 30, 2014 at 22:20 UTC 79bc4ef3686bc6795aa79a1d4aa6d3060a2cbd93

2 files changed +18 -1

git-filter-branch.sh

+7 -1

@@ -332,7 +332,13 @@ while read commit parents; do

332 parentstr=

333 for parent in $parents; do

334 for reparent in $(map "$parent"); do

335 - parentstr="$parentstr -p $reparent"

335 + case "$parentstr " in

336 + *" -p $reparent "*)

337 + ;;

338 + *)

339 + parentstr="$parentstr -p $reparent"

340 + ;;

341 + esac

342 done

343 done

344 if [ "$filter_parent" ]; then

t/t7003-filter-branch.sh

+11

@@ -308,6 +308,17 @@ test_expect_success 'Prune empty commits' '

308 test_cmp expect actual

309 '

310

311 +test_expect_success 'prune empty collapsed merges' '

312 + test_config merge.ff false &&

313 + git rev-list HEAD >expect &&

314 + test_commit to_remove_2 &&

315 + git reset --hard HEAD^ &&

316 + test_merge non-ff to_remove_2 &&

317 + git filter-branch -f --index-filter "git update-index --remove to_remove_2.t" --prune-empty HEAD &&

318 + git rev-list HEAD >actual &&

319 + test_cmp expect actual

320 +'

321 +

322 test_expect_success '--remap-to-ancestor with filename filters' '

323 git checkout master &&

324 git reset --hard A &&