Merge pull request #214 from fiddlerwoaroof/wave/km71-edit-formula

improvise-km71: edit a formula from the formula panel, in place

context/test-evidence/command.md

@@ -5655,6 +5655,46 @@ across two independently built ones. If a future refactor made the fixture
 share one map, or share one `RandomState`, the second assertion fails. Without
 this test the law would then pass everything and look healthy.
 
+### changing_the_target_renames_the_formula_in_its_own_place
+
+improvise-km71. This is the test that separates "edit" from "add". The rival
+was the first build: `commit-buffer formula` was resolved in `parse_commit_kind`,
+where the registry's parse-first rule never reaches the mode, so every edit
+became an `AddFormula`. `committing_an_edit_replaces_the_formula_in_place`
+**passed** under that rival, because `add_formula` upserts by
+`(target, target_category)` and an edit that keeps its target lands in the same
+slot. Injected on purpose (the commit emits `AddFormula` for the replace kind):
+this test, the rename-status test, the collision test, the parse-error test and
+both concurrency-refusal tests fail, and the in-place test passes. A rename is the input the upsert cannot fake. The fixture has three
+formulas with the cursor on index 1, so "the one under the cursor" is not also
+"the first" or "the last".
+
+### an_edit_lands_on_its_formula_after_an_earlier_one_is_deleted_meanwhile
+
+improvise-km71. The capture is made when the editor opens and never re-read
+from the cursor. Rival: `ReplaceFormula` resolves its formula from
+`formula_cursor` at commit. The fixture deletes `Profit` (index 0) while the
+editor is open on `Tax` (index 1), so cursor 1 now names `Margin`. The rival
+rewrote `Margin`, and this test fails, along with
+`an_edit_whose_formula_was_deleted_meanwhile_refuses_out_loud` and
+`an_edit_whose_formula_was_changed_meanwhile_refuses_out_loud`. The other nine
+formula-edit tests pass under it, because none of them moves the list.
+
+### an_edit_whose_formula_was_changed_meanwhile_refuses_out_loud
+
+improvise-km71. Another client rewrote `Tax`'s text but kept its target, so the
+id still resolves. Only the `was` check can see this. Rival: the `was` filter
+deleted. This test is the only one that fails. That is the case for keeping
+`was` after improvise-sboz gives formulas a stable id: a concurrent replace
+keeps the id.
+
+### a_rename_onto_another_formulas_target_refuses_and_keeps_both
+
+improvise-km71. Rival: `Model::replace_formula`'s collision check disabled.
+This test and `replace_formula_refuses_to_displace_another_formula` fail.
+Without the check, renaming `Tax` to `Margin` leaves two formulas with one
+identity, and `formula(&id)` then finds the first.
+
 ### a_fresh_session_has_no_history_to_step_back_through
 
 improvise-lxg0. `project.rs::fresh_view` built a new session's slice by folding
@@ -5930,6 +5970,16 @@ host's `Normal`, and nothing else different. `install_workbook` needs no
 change of its own, because both of its callers (`LoadModel`,
 `AcceptWizardModel`) run inside `apply_effects`, which settles after the batch.
 
+### renaming_a_formula_outside_measure_refuses_and_keeps_the_editor
+
+improvise-kb1d, found by the pre-merge review of #214 and by ChatGPT Codex (P1).
+The fixture has a Region-targeted formula at index 1, between two `_Measure`
+formulas, because every other km71 test used `_Measure`, whose items are
+derived from the formula list and cannot show a stranded item. Rival: the guard
+in `Model::replace_formula` disabled. This test fails on the formula list, and
+`replace_formula_refuses_to_rename_a_target_outside_measure` in core fails too.
+
+
 ### `an_untouched_pivot_edit_of_a_misread_value_writes_nothing`
 ### `an_untouched_records_edit_of_a_misread_value_writes_nothing`