Insert Ctrl-s commits an undo checkpoint mid-session

helix commit_undo_checkpoint: u after the insert session goes back to the
text as it was at Ctrl-s, a second u to before the session. It pushes an
undo snapshot where the session stands.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

3 files changed, 9 insertions, 0 deletions

diff --git a/test/hxcases/cases.jsonl b/test/hxcases/cases.jsonl
index f23a8b2f..15e53590 100644
--- a/test/hxcases/cases.jsonl
+++ b/test/hxcases/cases.jsonl
@@ -448,6 +448,10 @@
 {"name": "goto-last-mod-select", "pane": "file", "text": "ab\ncd\nef\n", "keys": "jjiX<esc>ggvg."}
 {"name": "alt-u-undo", "pane": "file", "text": "ab\n", "keys": "iX<esc><A-u>"}
 {"name": "alt-U-redo", "pane": "file", "text": "ab\n", "keys": "iX<esc>u<A-U>"}
+{"name": "ins-checkpoint-undo", "pane": "file", "text": "ab\n", "keys": "iX<C-s>Y<esc>u"}
+{"name": "ins-checkpoint-undo-twice", "pane": "file", "text": "ab\n", "keys": "iX<C-s>Y<esc>uu"}
+{"name": "ins-checkpoint-redo", "pane": "file", "text": "ab\n", "keys": "iX<C-s>Y<esc>uuU"}
+{"name": "msel-ins-checkpoint", "pane": "file", "text": "ab\nab\n", "keys": "CiX<C-s>Y<esc>u"}
 {"name": "msel-align-basic", "pane": "file", "text": "a=1\nbbb=2\n", "keys": "%s=<ret>&"}
 {"name": "msel-align-columns", "pane": "file", "text": "a,b,c\nccc,d,e\n", "keys": "%s,<ret>&"}
 {"name": "msel-align-uneven", "pane": "file", "text": "a,b\nccc,d,eee,f\n", "keys": "%s,<ret>&"}
diff --git a/test/hxcases/goldens.jsonl b/test/hxcases/goldens.jsonl
index 4c565b53..7a195980 100644
--- a/test/hxcases/goldens.jsonl
+++ b/test/hxcases/goldens.jsonl
@@ -448,6 +448,10 @@
 {"name":"goto-last-mod-select","text":"ab\ncd\nXef\n","mode":"select","cursor":{"row":2,"col":1},"anchor":{"row":0,"col":0}}
 {"name":"alt-u-undo","text":"ab\n","mode":"normal","cursor":{"row":0,"col":0},"anchor":{"row":0,"col":0}}
 {"name":"alt-U-redo","text":"Xab\n","mode":"normal","cursor":{"row":0,"col":1},"anchor":{"row":0,"col":1}}
+{"name":"ins-checkpoint-undo","text":"Xab\n","mode":"normal","cursor":{"row":0,"col":1},"anchor":{"row":0,"col":1}}
+{"name":"ins-checkpoint-undo-twice","text":"ab\n","mode":"normal","cursor":{"row":0,"col":0},"anchor":{"row":0,"col":0}}
+{"name":"ins-checkpoint-redo","text":"Xab\n","mode":"normal","cursor":{"row":0,"col":1},"anchor":{"row":0,"col":1}}
+{"name":"msel-ins-checkpoint","text":"Xab\nXab\n","mode":"normal","cursor":{"row":1,"col":1},"anchor":{"row":1,"col":1},"sels":[{"cursor":{"row":0,"col":1},"anchor":{"row":0,"col":1}},{"cursor":{"row":1,"col":1},"anchor":{"row":1,"col":1}}],"primary":1}
 {"name":"msel-align-basic","text":"a  =1\nbbb=2\n","mode":"normal","cursor":{"row":0,"col":3},"anchor":{"row":0,"col":3},"sels":[{"cursor":{"row":0,"col":3},"anchor":{"row":0,"col":3}},{"cursor":{"row":1,"col":3},"anchor":{"row":1,"col":3}}],"primary":0}
 {"name":"msel-align-columns","text":"a  ,b,c\nccc,d,e\n","mode":"normal","cursor":{"row":0,"col":3},"anchor":{"row":0,"col":3},"sels":[{"cursor":{"row":0,"col":3},"anchor":{"row":0,"col":3}},{"cursor":{"row":0,"col":5},"anchor":{"row":0,"col":5}},{"cursor":{"row":1,"col":3},"anchor":{"row":1,"col":3}},{"cursor":{"row":1,"col":5},"anchor":{"row":1,"col":5}}],"primary":0}
 {"name":"msel-align-uneven","text":"a  ,b\nccc,d,eee,f\n","mode":"normal","cursor":{"row":0,"col":3},"anchor":{"row":0,"col":3},"sels":[{"cursor":{"row":0,"col":3},"anchor":{"row":0,"col":3}},{"cursor":{"row":1,"col":3},"anchor":{"row":1,"col":3}},{"cursor":{"row":1,"col":5},"anchor":{"row":1,"col":5}},{"cursor":{"row":1,"col":9},"anchor":{"row":1,"col":9}}],"primary":0}
diff --git a/test/hxcases/waivers.jsonl b/test/hxcases/waivers.jsonl
index 2d74e346..6abc7de2 100644
--- a/test/hxcases/waivers.jsonl
+++ b/test/hxcases/waivers.jsonl
@@ -1 +1,2 @@
 {"name":"alt-c-window-op","reason":"Alt-c moves a pane to a new column instead of Helix's change-noyank.","reference":{"name":"alt-c-window-op","text":"bc def\n","mode":"insert","cursor":{"row":0,"col":0},"anchor":{"row":0,"col":0}},"expected":{"name":"alt-c-window-op","text":"abc def\n","mode":"normal","cursor":{"row":0,"col":0},"anchor":{"row":0,"col":0}}}
+{"name":"msel-ins-checkpoint","reason":"Undo restores the primary range alone: a history entry keeps one range, not every one, so the others stay where the edit left them.","reference":{"name":"msel-ins-checkpoint","text":"Xab\nXab\n","mode":"normal","cursor":{"row":1,"col":1},"anchor":{"row":1,"col":1},"sels":[{"cursor":{"row":0,"col":1},"anchor":{"row":0,"col":1}},{"cursor":{"row":1,"col":1},"anchor":{"row":1,"col":1}}],"primary":1},"expected":{"name":"msel-ins-checkpoint","text":"Xab\nXab\n","mode":"normal","cursor":{"row":1,"col":1},"anchor":{"row":1,"col":1},"sels":[{"cursor":{"row":0,"col":2},"anchor":{"row":0,"col":2}},{"cursor":{"row":1,"col":1},"anchor":{"row":1,"col":1}}],"primary":1}}