bcdb475 · helix · git.iko.soy

git.iko.soy/helix

Fix transaction composition order in History::changes_since (#4981)

* Add a undo/redo split test case for crossing branches * history: Switch up/down transaction chaining order The old code tends to work in practice because, usually, either up_txns or down_txns are empty. When both have contents though, we can run into a panic trying to compose them all since they will disagree on the length of the text. This fixes the panic test case in the parent commit.

commitbcdb475b71b0fbabce57344ac8d2575c23b1bbe0 authorMichael Davis <mcarsondavis@gmail.com> dateFri 2 Dec 2022, 21:09 (4 years ago) parentdc00291

2 files changed+26−1

compare with master

unifiedsplit

helix-core/src/history.rs+1−1 helix-term/tests/test/splits.rs+25

helix-core/src/history.rs+1−1

@@ -131,7 +131,7 @@ impl History {

131131 .map(|&n| self.revisions[n].inversion.clone());

132132 let down_txns = down.iter().map(|&n| self.revisions[n].transaction.clone());

133133

134− up_txns.chain(down_txns).reduce(|acc, tx| tx.compose(acc))

134+ down_txns.chain(up_txns).reduce(|acc, tx| tx.compose(acc))

135135 }

136136

137137 /// Undo the last edit.

helix-term/tests/test/splits.rs+25

@@ -161,5 +161,30 @@ async fn test_changes_in_splits_apply_to_all_views() -> anyhow::Result<()> {

161161 ))

162162 .await?;

163163

164+ // See <https://github.com/helix-editor/helix/issues/4957>.

165+ // This sequence undoes part of the history and then adds new changes, creating a

166+ // new branch in the history tree. `View::sync_changes` applies transactions down

167+ // and up to the lowest common ancestor in the path between old and new revision

168+ // numbers. If we apply these up/down transactions in the wrong order, this case

169+ // panics.

170+ // The key sequence:

171+ // * 3[<space> Create three empty lines so we are at the end of the document.

172+ // * <C-w>v<C-s> Create a split and save that point at the end of the document

173+ // in the jumplist.

174+ // * <C-w>w Switch back to the first window.

175+ // * uu Undo twice (not three times which would bring us back to the

176+ // root of the tree).

177+ // * 3[<space> Create three empty lines. Now the end of the document is past

178+ // where it was on step 1.

179+ // * <C-w>q Close window 1, focusing window 2 and causing a sync. This step

180+ // panics if we don't apply in the right order.

181+ // * %d Clean up the buffer.

182+ test((

183+ "#[|]#",

184+ "3[<space><C-w>v<C-s><C-w>wuu3[<space><C-w>q%d",

185+ "#[|]#",

186+ ))

187+ .await?;

188+

164189 Ok(())

165190}