From bd810b88fdcfa9db068336951afd04653e7cf65a Mon Sep 17 00:00:00 2001
From: Farhan Yahaya <yahyafarhan48@gmail.com>
Date: Tue, 9 Dec 2025 17:11:31 +0000
Subject: [PATCH 1/7] fix: saving workflow with name same as deleted workflow

---
 .../js/collaborative-editor/types/workflow.ts |   8 +-
 .../types/workflow.test.ts                    | 101 ++++++++++++++++++
 lib/lightning/workflows.ex                    |  44 +++++++-
 lib/lightning/workflows/workflow.ex           |  13 +++
 test/lightning/workflows_test.exs             |  70 ++++++++++++
 5 files changed, 233 insertions(+), 3 deletions(-)
 create mode 100644 assets/test/collaborative-editor/types/workflow.test.ts

diff --git a/assets/js/collaborative-editor/types/workflow.ts b/assets/js/collaborative-editor/types/workflow.ts
index e8c794a079..870d2b78b0 100644
--- a/assets/js/collaborative-editor/types/workflow.ts
+++ b/assets/js/collaborative-editor/types/workflow.ts
@@ -17,14 +17,18 @@ import type { Trigger as TriggerType } from './trigger';
 /**
  * Zod schema for workflow validation
  *
- * Mirrors backend validation from lib/lightning/workflows/workflow.ex:81-89
+ * Mirrors backend validation from lib/lightning/workflows/workflow.ex:81-103
  */
 export const WorkflowSchema = z.object({
   id: z.string().uuid(),
   name: z
     .string()
     .min(1, "can't be blank")
-    .max(255, 'should be at most 255 character(s)'),
+    .max(255, 'should be at most 255 character(s)')
+    .refine(
+      name => !/_del\d*$/.test(name),
+      'cannot end with _del followed by digits'
+    ),
   lock_version: z.number().int(),
   deleted_at: z.string().nullable(),
 
diff --git a/assets/test/collaborative-editor/types/workflow.test.ts b/assets/test/collaborative-editor/types/workflow.test.ts
new file mode 100644
index 0000000000..eb52f2267d
--- /dev/null
+++ b/assets/test/collaborative-editor/types/workflow.test.ts
@@ -0,0 +1,101 @@
+import { describe, it, expect } from 'vitest';
+
+import { WorkflowSchema } from '#/collaborative-editor/types/workflow';
+
+describe('WorkflowSchema', () => {
+  describe('name validation', () => {
+    it('should reject names ending with _del followed by digits', () => {
+      const invalidData = {
+        id: '123e4567-e89b-12d3-a456-426614174000',
+        name: 'My Workflow_del0001',
+        lock_version: 1,
+        deleted_at: null,
+      };
+
+      const result = WorkflowSchema.safeParse(invalidData);
+      expect(result.success).toBe(false);
+    });
+
+    it('should reject names ending with _del without digits', () => {
+      const invalidData = {
+        id: '123e4567-e89b-12d3-a456-426614174000',
+        name: 'My Workflow_del',
+        lock_version: 1,
+        deleted_at: null,
+      };
+
+      const result = WorkflowSchema.safeParse(invalidData);
+      expect(result.success).toBe(false);
+    });
+
+    it('should reject names ending with _del followed by 3 digits', () => {
+      const invalidData = {
+        id: '123e4567-e89b-12d3-a456-426614174000',
+        name: 'My Workflow_del123',
+        lock_version: 1,
+        deleted_at: null,
+      };
+
+      const result = WorkflowSchema.safeParse(invalidData);
+      expect(result.success).toBe(false);
+    });
+
+    it('should reject names ending with _del followed by 5 digits', () => {
+      const invalidData = {
+        id: '123e4567-e89b-12d3-a456-426614174000',
+        name: 'My Workflow_del12345',
+        lock_version: 1,
+        deleted_at: null,
+      };
+
+      const result = WorkflowSchema.safeParse(invalidData);
+      expect(result.success).toBe(false);
+    });
+
+    it('should allow normal workflow names', () => {
+      const validData = {
+        id: '123e4567-e89b-12d3-a456-426614174000',
+        name: 'My Workflow',
+        lock_version: 1,
+        deleted_at: null,
+      };
+
+      const result = WorkflowSchema.safeParse(validData);
+      expect(result.success).toBe(true);
+    });
+
+    it('should allow names with _del in the middle', () => {
+      const validData = {
+        id: '123e4567-e89b-12d3-a456-426614174000',
+        name: 'My_del_Workflow',
+        lock_version: 1,
+        deleted_at: null,
+      };
+
+      const result = WorkflowSchema.safeParse(validData);
+      expect(result.success).toBe(true);
+    });
+
+    it('should reject multiple invalid formats', () => {
+      const testCases = [
+        'Test_del0001',
+        'Workflow_del9999',
+        'Another Workflow_del0000',
+        'Name_del',
+        'Workflow_del1',
+      ];
+
+      testCases.forEach(name => {
+        const data = {
+          id: '123e4567-e89b-12d3-a456-426614174000',
+          name,
+          lock_version: 1,
+          deleted_at: null,
+        };
+
+        const result = WorkflowSchema.safeParse(data);
+        expect(result.success).toBe(false);
+      });
+    });
+  });
+});
diff --git a/lib/lightning/workflows.ex b/lib/lightning/workflows.ex
index cbbfcc93d3..8c95ef4c8e 100644
--- a/lib/lightning/workflows.ex
+++ b/lib/lightning/workflows.ex
@@ -462,12 +462,16 @@ defmodule Lightning.Workflows do
         where: t.workflow_id == ^workflow.id
       )
 
+    new_name = generate_deleted_workflow_name(workflow)
+
     Multi.new()
     |> Multi.update(
       :workflow,
-      Workflow.request_deletion_changeset(workflow, %{
+      workflow
+      |> Workflow.request_deletion_changeset(%{
         "deleted_at" => DateTime.utc_now()
       })
+      |> Ecto.Changeset.put_change(:name, new_name)
     )
     |> Multi.insert(:audit, Audit.marked_for_deletion(workflow.id, actor))
     |> Multi.update_all(
@@ -486,6 +490,44 @@ defmodule Lightning.Workflows do
     end)
   end
 
+  defp generate_deleted_workflow_name(%Workflow{
+         name: name,
+         project_id: project_id
+       }) do
+    # Escape special regex characters in the workflow name
+    escaped_name = Regex.escape(name)
+    pattern = "^#{escaped_name}_del[0-9]+$"
+
+    # Find the workflow with the highest suffix by sorting names lexicographically
+    # This works because we zero-pad numbers: _del0001, _del0002, ..., _del0009, _del0010
+    highest_suffix_name =
+      from(w in Workflow,
+        where:
+          w.project_id == ^project_id and
+            not is_nil(w.deleted_at) and
+            fragment("? ~ ?", w.name, ^pattern),
+        order_by: [desc: w.name],
+        limit: 1,
+        select: w.name
+      )
+      |> Repo.one()
+
+    next_number =
+      case highest_suffix_name do
+        nil ->
+          1
+
+        name_with_suffix ->
+          case Regex.run(~r/_del(\d+)$/, name_with_suffix) do
+            [_, num] -> String.to_integer(num) + 1
+            _ -> 1
+          end
+      end
+
+    # Zero-pad to 4 digits to ensure proper lexicographic sorting
+    "#{name}_del#{String.pad_leading(Integer.to_string(next_number), 4, "0")}"
+  end
+
   defp notify_of_affected_kafka_triggers(%{triggers: triggers}) do
     triggers
     |> Enum.filter(&(&1.type == :kafka))
diff --git a/lib/lightning/workflows/workflow.ex b/lib/lightning/workflows/workflow.ex
index 9493f005cb..e44d795a1a 100644
--- a/lib/lightning/workflows/workflow.ex
+++ b/lib/lightning/workflows/workflow.ex
@@ -83,11 +83,24 @@ defmodule Lightning.Workflows.Workflow do
     |> assoc_constraint(:project)
     |> validate_number(:concurrency, greater_than_or_equal_to: 1)
     |> validate_required([:name])
+    |> validate_name_not_deleted_format()
     |> unique_constraint([:name, :project_id],
       message: "a workflow with this name already exists in this project."
     )
   end
 
+  defp validate_name_not_deleted_format(changeset) do
+    validate_change(changeset, :name, fn :name, name ->
+      if Regex.match?(~r/_del\d*$/, name) do
+        [
+          name: "cannot end with _del followed by digits"
+        ]
+      else
+        []
+      end
+    end)
+  end
+
   def request_deletion_changeset(workflow, attrs) do
     workflow
     |> cast(attrs, [:deleted_at])
diff --git a/test/lightning/workflows_test.exs b/test/lightning/workflows_test.exs
index edd6d80755..73db9286c4 100644
--- a/test/lightning/workflows_test.exs
+++ b/test/lightning/workflows_test.exs
@@ -833,6 +833,76 @@ defmodule Lightning.WorkflowsTest do
       assert_received %KafkaTriggerUpdated{trigger_id: ^kafka_trigger_2_id}
       assert_received %KafkaTriggerUpdated{trigger_id: ^kafka_trigger_1_id}
     end
+
+    test "mark_for_deletion/3 renames workflow with _del suffix" do
+      # Use a separate project to avoid pollution from setup
+      project = insert(:project)
+      user = insert(:user)
+      w1 = insert(:workflow, project: project, name: "Test Workflow")
+
+      assert {:ok, %{workflow: workflow}} = Workflows.mark_for_deletion(w1, user)
+      assert workflow.name == "Test Workflow_del0001"
+
+      # Test incrementing when deleting another workflow with the same name
+      w2 = insert(:workflow, project: project, name: "Test Workflow")
+
+      assert {:ok, %{workflow: workflow2}} =
+               Workflows.mark_for_deletion(w2, user)
+
+      assert workflow2.name == "Test Workflow_del0002"
+
+      # Test incrementing again
+      w3 = insert(:workflow, project: project, name: "Test Workflow")
+
+      assert {:ok, %{workflow: workflow3}} =
+               Workflows.mark_for_deletion(w3, user)
+
+      assert workflow3.name == "Test Workflow_del0003"
+    end
+
+    test "change_workflow/2 rejects names ending with _del followed by digits" do
+      project = insert(:project)
+      workflow = insert(:workflow, project: project, name: "Original Name")
+
+      # Should reject _del with any digits
+      changeset =
+        Workflows.change_workflow(workflow, %{name: "My Workflow_del0001"})
+
+      refute changeset.valid?
+
+      assert %{name: [error]} = errors_on(changeset)
+
+      assert error =~
+               "cannot end with _del followed by digits"
+
+      # Should also reject _del with no digits
+      changeset = Workflows.change_workflow(workflow, %{name: "My Workflow_del"})
+      refute changeset.valid?
+
+      assert %{name: [error]} = errors_on(changeset)
+      assert error =~ "cannot end with _del followed by digits"
+
+      # Should also reject _del with 3 digits
+      changeset =
+        Workflows.change_workflow(workflow, %{name: "My Workflow_del123"})
+
+      refute changeset.valid?
+
+      assert %{name: [error]} = errors_on(changeset)
+      assert error =~ "cannot end with _del followed by digits"
+
+      # Valid names should work (not ending with _del)
+      changeset = Workflows.change_workflow(workflow, %{name: "My Workflow"})
+      errors = errors_on(changeset)
+      assert Map.get(errors, :name) == nil
+
+      # Valid name with _del in the middle
+      changeset =
+        Workflows.change_workflow(workflow, %{name: "My_del_Workflow"})
+
+      errors = errors_on(changeset)
+      assert Map.get(errors, :name) == nil
+    end
   end
 
   describe "get_workflows_for/2" do

From ffb24cb66f3bd1f3c530aeda10db88733994076a Mon Sep 17 00:00:00 2001
From: Farhan Yahaya <yahyafarhan48@gmail.com>
Date: Tue, 9 Dec 2025 17:49:08 +0000
Subject: [PATCH 2/7] chore: update changelog

---
 CHANGELOG.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fce59acdec..7547a1cb92 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,9 @@ and this project adheres to
 
 ### Fixed
 
+- Fix saving workflow with same name as deleted workflow
+  [#4165](https://github.com/OpenFn/lightning/pull/4165)
+
 ## [2.15.0-pre4] - 2025-12-08
 
 ### Added

From fbfa34d99d7bbaff99570752e38e364525d5c776 Mon Sep 17 00:00:00 2001
From: Farhan Yahaya <yahyafarhan48@gmail.com>
Date: Wed, 10 Dec 2025 11:54:29 +0000
Subject: [PATCH 3/7] fix: update wording & reduce collision

---
 .../js/collaborative-editor/types/workflow.ts |   6 +-
 .../types/workflow.test.ts                    | 101 ------------------
 lib/lightning/workflows.ex                    |   5 +-
 lib/lightning/workflows/workflow.ex           |  16 +--
 test/lightning/workflows/workflow_test.exs    |   2 +-
 test/lightning/workflows_test.exs             |  69 ++++++------
 .../live/workflow_live/edit_test.exs          |   4 +-
 7 files changed, 39 insertions(+), 164 deletions(-)
 delete mode 100644 assets/test/collaborative-editor/types/workflow.test.ts

diff --git a/assets/js/collaborative-editor/types/workflow.ts b/assets/js/collaborative-editor/types/workflow.ts
index 870d2b78b0..cace5d8c13 100644
--- a/assets/js/collaborative-editor/types/workflow.ts
+++ b/assets/js/collaborative-editor/types/workflow.ts
@@ -24,11 +24,7 @@ export const WorkflowSchema = z.object({
   name: z
     .string()
     .min(1, "can't be blank")
-    .max(255, 'should be at most 255 character(s)')
-    .refine(
-      name => !/_del\d*$/.test(name),
-      'cannot end with _del followed by digits'
-    ),
+    .max(255, 'should be at most 255 character(s)'),
   lock_version: z.number().int(),
   deleted_at: z.string().nullable(),
 
diff --git a/assets/test/collaborative-editor/types/workflow.test.ts b/assets/test/collaborative-editor/types/workflow.test.ts
deleted file mode 100644
index eb52f2267d..0000000000
--- a/assets/test/collaborative-editor/types/workflow.test.ts
+++ /dev/null
@@ -1,101 +0,0 @@
-import { describe, it, expect } from 'vitest';
-
-import { WorkflowSchema } from '#/collaborative-editor/types/workflow';
-
-describe('WorkflowSchema', () => {
-  describe('name validation', () => {
-    it('should reject names ending with _del followed by digits', () => {
-      const invalidData = {
-        id: '123e4567-e89b-12d3-a456-426614174000',
-        name: 'My Workflow_del0001',
-        lock_version: 1,
-        deleted_at: null,
-      };
-
-      const result = WorkflowSchema.safeParse(invalidData);
-      expect(result.success).toBe(false);
-    });
-
-    it('should reject names ending with _del without digits', () => {
-      const invalidData = {
-        id: '123e4567-e89b-12d3-a456-426614174000',
-        name: 'My Workflow_del',
-        lock_version: 1,
-        deleted_at: null,
-      };
-
-      const result = WorkflowSchema.safeParse(invalidData);
-      expect(result.success).toBe(false);
-    });
-
-    it('should reject names ending with _del followed by 3 digits', () => {
-      const invalidData = {
-        id: '123e4567-e89b-12d3-a456-426614174000',
-        name: 'My Workflow_del123',
-        lock_version: 1,
-        deleted_at: null,
-      };
-
-      const result = WorkflowSchema.safeParse(invalidData);
-      expect(result.success).toBe(false);
-    });
-
-    it('should reject names ending with _del followed by 5 digits', () => {
-      const invalidData = {
-        id: '123e4567-e89b-12d3-a456-426614174000',
-        name: 'My Workflow_del12345',
-        lock_version: 1,
-        deleted_at: null,
-      };
-
-      const result = WorkflowSchema.safeParse(invalidData);
-      expect(result.success).toBe(false);
-    });
-
-    it('should allow normal workflow names', () => {
-      const validData = {
-        id: '123e4567-e89b-12d3-a456-426614174000',
-        name: 'My Workflow',
-        lock_version: 1,
-        deleted_at: null,
-      };
-
-      const result = WorkflowSchema.safeParse(validData);
-      expect(result.success).toBe(true);
-    });
-
-    it('should allow names with _del in the middle', () => {
-      const validData = {
-        id: '123e4567-e89b-12d3-a456-426614174000',
-        name: 'My_del_Workflow',
-        lock_version: 1,
-        deleted_at: null,
-      };
-
-      const result = WorkflowSchema.safeParse(validData);
-      expect(result.success).toBe(true);
-    });
-
-    it('should reject multiple invalid formats', () => {
-      const testCases = [
-        'Test_del0001',
-        'Workflow_del9999',
-        'Another Workflow_del0000',
-        'Name_del',
-        'Workflow_del1',
-      ];
-
-      testCases.forEach(name => {
-        const data = {
-          id: '123e4567-e89b-12d3-a456-426614174000',
-          name,
-          lock_version: 1,
-          deleted_at: null,
-        };
-
-        const result = WorkflowSchema.safeParse(data);
-        expect(result.success).toBe(false);
-      });
-    });
-  });
-});
diff --git a/lib/lightning/workflows.ex b/lib/lightning/workflows.ex
index 8c95ef4c8e..878ddba367 100644
--- a/lib/lightning/workflows.ex
+++ b/lib/lightning/workflows.ex
@@ -499,7 +499,7 @@ defmodule Lightning.Workflows do
     pattern = "^#{escaped_name}_del[0-9]+$"
 
     # Find the workflow with the highest suffix by sorting names lexicographically
-    # This works because we zero-pad numbers: _del0001, _del0002, ..., _del0009, _del0010
+    # This works because we zero-pad numbers: _del01, _del02, ..., _del09, _del10
     highest_suffix_name =
       from(w in Workflow,
         where:
@@ -524,8 +524,7 @@ defmodule Lightning.Workflows do
           end
       end
 
-    # Zero-pad to 4 digits to ensure proper lexicographic sorting
-    "#{name}_del#{String.pad_leading(Integer.to_string(next_number), 4, "0")}"
+    "#{name}_del#{String.pad_leading(Integer.to_string(next_number), 2, "0")}"
   end
 
   defp notify_of_affected_kafka_triggers(%{triggers: triggers}) do
diff --git a/lib/lightning/workflows/workflow.ex b/lib/lightning/workflows/workflow.ex
index e44d795a1a..d6bfc2f9ce 100644
--- a/lib/lightning/workflows/workflow.ex
+++ b/lib/lightning/workflows/workflow.ex
@@ -83,24 +83,12 @@ defmodule Lightning.Workflows.Workflow do
     |> assoc_constraint(:project)
     |> validate_number(:concurrency, greater_than_or_equal_to: 1)
     |> validate_required([:name])
-    |> validate_name_not_deleted_format()
     |> unique_constraint([:name, :project_id],
-      message: "a workflow with this name already exists in this project."
+      message:
+        "a workflow with this name already exists(possibly pending deletion) in this project."
     )
   end
 
-  defp validate_name_not_deleted_format(changeset) do
-    validate_change(changeset, :name, fn :name, name ->
-      if Regex.match?(~r/_del\d*$/, name) do
-        [
-          name: "cannot end with _del followed by digits"
-        ]
-      else
-        []
-      end
-    end)
-  end
-
   def request_deletion_changeset(workflow, attrs) do
     workflow
     |> cast(attrs, [:deleted_at])
diff --git a/test/lightning/workflows/workflow_test.exs b/test/lightning/workflows/workflow_test.exs
index 652bfd5026..26204d90e4 100644
--- a/test/lightning/workflows/workflow_test.exs
+++ b/test/lightning/workflows/workflow_test.exs
@@ -79,7 +79,7 @@ defmodule Lightning.Workflows.WorkflowTest do
         |> Workflow.changeset(%{name: "w1", project_id: p1.id})
         |> Repo.insert()
 
-      assert "a workflow with this name already exists in this project." in errors_on(
+      assert "a workflow with this name already exists(possibly pending deletion) in this project." in errors_on(
                cs
              ).name
 
diff --git a/test/lightning/workflows_test.exs b/test/lightning/workflows_test.exs
index 73db9286c4..c8721068bf 100644
--- a/test/lightning/workflows_test.exs
+++ b/test/lightning/workflows_test.exs
@@ -52,7 +52,7 @@ defmodule Lightning.WorkflowsTest do
 
       assert %{
                name: [
-                 "a workflow with this name already exists in this project."
+                 "a workflow with this name already exists(possibly pending deletion) in this project."
                ]
              } = errors_on(changeset)
 
@@ -841,7 +841,7 @@ defmodule Lightning.WorkflowsTest do
       w1 = insert(:workflow, project: project, name: "Test Workflow")
 
       assert {:ok, %{workflow: workflow}} = Workflows.mark_for_deletion(w1, user)
-      assert workflow.name == "Test Workflow_del0001"
+      assert workflow.name == "Test Workflow_del01"
 
       # Test incrementing when deleting another workflow with the same name
       w2 = insert(:workflow, project: project, name: "Test Workflow")
@@ -849,7 +849,7 @@ defmodule Lightning.WorkflowsTest do
       assert {:ok, %{workflow: workflow2}} =
                Workflows.mark_for_deletion(w2, user)
 
-      assert workflow2.name == "Test Workflow_del0002"
+      assert workflow2.name == "Test Workflow_del02"
 
       # Test incrementing again
       w3 = insert(:workflow, project: project, name: "Test Workflow")
@@ -857,51 +857,42 @@ defmodule Lightning.WorkflowsTest do
       assert {:ok, %{workflow: workflow3}} =
                Workflows.mark_for_deletion(w3, user)
 
-      assert workflow3.name == "Test Workflow_del0003"
+      assert workflow3.name == "Test Workflow_del03"
     end
 
-    test "change_workflow/2 rejects names ending with _del followed by digits" do
+    test "allows reusing workflow name after marking for deletion, then validates error when using deleted workflow name" do
       project = insert(:project)
-      workflow = insert(:workflow, project: project, name: "Original Name")
-
-      # Should reject _del with any digits
-      changeset =
-        Workflows.change_workflow(workflow, %{name: "My Workflow_del0001"})
-
-      refute changeset.valid?
-
-      assert %{name: [error]} = errors_on(changeset)
-
-      assert error =~
-               "cannot end with _del followed by digits"
-
-      # Should also reject _del with no digits
-      changeset = Workflows.change_workflow(workflow, %{name: "My Workflow_del"})
-      refute changeset.valid?
-
-      assert %{name: [error]} = errors_on(changeset)
-      assert error =~ "cannot end with _del followed by digits"
+      user = insert(:user)
+      w1 = insert(:workflow, project: project, name: "My Workflow")
 
-      # Should also reject _del with 3 digits
-      changeset =
-        Workflows.change_workflow(workflow, %{name: "My Workflow_del123"})
+      # Mark workflow for deletion
+      assert {:ok, %{workflow: deleted_workflow}} =
+               Workflows.mark_for_deletion(w1, user)
 
-      refute changeset.valid?
+      assert deleted_workflow.name == "My Workflow_del01"
 
-      assert %{name: [error]} = errors_on(changeset)
-      assert error =~ "cannot end with _del followed by digits"
+      # Should be able to create a new workflow with the original name
+      assert {:ok, new_workflow} =
+               Workflows.save_workflow(
+                 %{name: "My Workflow", project_id: project.id},
+                 user
+               )
 
-      # Valid names should work (not ending with _del)
-      changeset = Workflows.change_workflow(workflow, %{name: "My Workflow"})
-      errors = errors_on(changeset)
-      assert Map.get(errors, :name) == nil
+      assert new_workflow.name == "My Workflow"
+      assert new_workflow.deleted_at == nil
 
-      # Valid name with _del in the middle
-      changeset =
-        Workflows.change_workflow(workflow, %{name: "My_del_Workflow"})
+      # Should NOT be able to create another workflow with the deleted workflow's name
+      assert {:error, changeset} =
+               Workflows.save_workflow(
+                 %{name: "My Workflow_del01", project_id: project.id},
+                 user
+               )
 
-      errors = errors_on(changeset)
-      assert Map.get(errors, :name) == nil
+      assert errors_on(changeset) == %{
+               name: [
+                 "a workflow with this name already exists(possibly pending deletion) in this project."
+               ]
+             }
     end
   end
 
diff --git a/test/lightning_web/live/workflow_live/edit_test.exs b/test/lightning_web/live/workflow_live/edit_test.exs
index efbaafaeea..5461bde623 100644
--- a/test/lightning_web/live/workflow_live/edit_test.exs
+++ b/test/lightning_web/live/workflow_live/edit_test.exs
@@ -1229,7 +1229,9 @@ defmodule LightningWeb.WorkflowLive.EditTest do
         })
         |> render_submit()
 
-      assert html =~ "a workflow with this name already exists in this project."
+      assert html =~
+               "a workflow with this name already exists(possibly pending deletion) in this project."
+
       assert html =~ "Workflow could not be saved"
 
       assert view

From 6d7c8a4215260f56105e96ae4fd502b51dabe286 Mon Sep 17 00:00:00 2001
From: Taylor Downs <taylor@openfn.org>
Date: Wed, 10 Dec 2025 18:18:07 +0100
Subject: [PATCH 4/7] fix small typo and caps in validation message

---
 lib/lightning/workflows/workflow.ex                 | 2 +-
 test/lightning/workflows/workflow_test.exs          | 2 +-
 test/lightning/workflows_test.exs                   | 4 ++--
 test/lightning_web/live/workflow_live/edit_test.exs | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/lightning/workflows/workflow.ex b/lib/lightning/workflows/workflow.ex
index d6bfc2f9ce..1bc3cc02c4 100644
--- a/lib/lightning/workflows/workflow.ex
+++ b/lib/lightning/workflows/workflow.ex
@@ -85,7 +85,7 @@ defmodule Lightning.Workflows.Workflow do
     |> validate_required([:name])
     |> unique_constraint([:name, :project_id],
       message:
-        "a workflow with this name already exists(possibly pending deletion) in this project."
+        "A workflow with this name already exists (possibly pending deletion) in this project."
     )
   end
 
diff --git a/test/lightning/workflows/workflow_test.exs b/test/lightning/workflows/workflow_test.exs
index 26204d90e4..fb70ebf476 100644
--- a/test/lightning/workflows/workflow_test.exs
+++ b/test/lightning/workflows/workflow_test.exs
@@ -79,7 +79,7 @@ defmodule Lightning.Workflows.WorkflowTest do
         |> Workflow.changeset(%{name: "w1", project_id: p1.id})
         |> Repo.insert()
 
-      assert "a workflow with this name already exists(possibly pending deletion) in this project." in errors_on(
+      assert "a workflow with this name already exists (possibly pending deletion) in this project." in errors_on(
                cs
              ).name
 
diff --git a/test/lightning/workflows_test.exs b/test/lightning/workflows_test.exs
index c8721068bf..ca1abaf810 100644
--- a/test/lightning/workflows_test.exs
+++ b/test/lightning/workflows_test.exs
@@ -52,7 +52,7 @@ defmodule Lightning.WorkflowsTest do
 
       assert %{
                name: [
-                 "a workflow with this name already exists(possibly pending deletion) in this project."
+                 "A workflow with this name already exists (possibly pending deletion) in this project."
                ]
              } = errors_on(changeset)
 
@@ -890,7 +890,7 @@ defmodule Lightning.WorkflowsTest do
 
       assert errors_on(changeset) == %{
                name: [
-                 "a workflow with this name already exists(possibly pending deletion) in this project."
+                 "a workflow with this name already exists (possibly pending deletion) in this project."
                ]
              }
     end
diff --git a/test/lightning_web/live/workflow_live/edit_test.exs b/test/lightning_web/live/workflow_live/edit_test.exs
index 5461bde623..b0ff7b0717 100644
--- a/test/lightning_web/live/workflow_live/edit_test.exs
+++ b/test/lightning_web/live/workflow_live/edit_test.exs
@@ -1230,7 +1230,7 @@ defmodule LightningWeb.WorkflowLive.EditTest do
         |> render_submit()
 
       assert html =~
-               "a workflow with this name already exists(possibly pending deletion) in this project."
+               "A workflow with this name already exists (possibly pending deletion) in this project."
 
       assert html =~ "Workflow could not be saved"
 

From 7a168946d0fa4dea5ffa614bcdcf13f8ac8ce4a3 Mon Sep 17 00:00:00 2001
From: Taylor Downs <taylor@openfn.org>
Date: Wed, 10 Dec 2025 18:19:04 +0100
Subject: [PATCH 5/7] save work

---
 test/lightning/workflows/workflow_test.exs | 2 +-
 test/lightning/workflows_test.exs          | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/lightning/workflows/workflow_test.exs b/test/lightning/workflows/workflow_test.exs
index fb70ebf476..efccdec483 100644
--- a/test/lightning/workflows/workflow_test.exs
+++ b/test/lightning/workflows/workflow_test.exs
@@ -79,7 +79,7 @@ defmodule Lightning.Workflows.WorkflowTest do
         |> Workflow.changeset(%{name: "w1", project_id: p1.id})
         |> Repo.insert()
 
-      assert "a workflow with this name already exists (possibly pending deletion) in this project." in errors_on(
+      assert "A workflow with this name already exists (possibly pending deletion) in this project." in errors_on(
                cs
              ).name
 
diff --git a/test/lightning/workflows_test.exs b/test/lightning/workflows_test.exs
index ca1abaf810..ab5f9a0c54 100644
--- a/test/lightning/workflows_test.exs
+++ b/test/lightning/workflows_test.exs
@@ -890,7 +890,7 @@ defmodule Lightning.WorkflowsTest do
 
       assert errors_on(changeset) == %{
                name: [
-                 "a workflow with this name already exists (possibly pending deletion) in this project."
+                 "A workflow with this name already exists (possibly pending deletion) in this project."
                ]
              }
     end

From b2e9e0cc8f8361bcb733ee38fae443b499d21463 Mon Sep 17 00:00:00 2001
From: Taylor Downs <taylor@openfn.org>
Date: Thu, 11 Dec 2025 11:23:15 +0100
Subject: [PATCH 6/7] more

---
 lib/lightning/workflows.ex        | 41 +++++++++++--------------------
 test/lightning/workflows_test.exs | 31 +++++++++++++++++++----
 2 files changed, 40 insertions(+), 32 deletions(-)

diff --git a/lib/lightning/workflows.ex b/lib/lightning/workflows.ex
index 878ddba367..277076f749 100644
--- a/lib/lightning/workflows.ex
+++ b/lib/lightning/workflows.ex
@@ -462,7 +462,7 @@ defmodule Lightning.Workflows do
         where: t.workflow_id == ^workflow.id
       )
 
-    new_name = generate_deleted_workflow_name(workflow)
+    new_name = append_del_to_name(workflow)
 
     Multi.new()
     |> Multi.update(
@@ -490,41 +490,28 @@ defmodule Lightning.Workflows do
     end)
   end
 
-  defp generate_deleted_workflow_name(%Workflow{
-         name: name,
-         project_id: project_id
-       }) do
-    # Escape special regex characters in the workflow name
-    escaped_name = Regex.escape(name)
-    pattern = "^#{escaped_name}_del[0-9]+$"
+  defp append_del_to_name(%Workflow{name: name, project_id: project_id}) do
+    base_name = "#{name}_del"
 
-    # Find the workflow with the highest suffix by sorting names lexicographically
-    # This works because we zero-pad numbers: _del01, _del02, ..., _del09, _del10
-    highest_suffix_name =
+    existing_names =
       from(w in Workflow,
         where:
           w.project_id == ^project_id and
-            not is_nil(w.deleted_at) and
-            fragment("? ~ ?", w.name, ^pattern),
-        order_by: [desc: w.name],
-        limit: 1,
+            (w.name == ^base_name or like(w.name, ^"#{base_name}%")),
         select: w.name
       )
-      |> Repo.one()
+      |> Repo.all()
+      |> MapSet.new()
 
-    next_number =
-      case highest_suffix_name do
-        nil ->
-          1
+    find_available_name(base_name, existing_names)
+  end
 
-        name_with_suffix ->
-          case Regex.run(~r/_del(\d+)$/, name_with_suffix) do
-            [_, num] -> String.to_integer(num) + 1
-            _ -> 1
-          end
-      end
+  defp find_available_name(base_name, existing_names, n \\ 0) do
+    candidate = if n == 0, do: base_name, else: "#{base_name}#{n}"
 
-    "#{name}_del#{String.pad_leading(Integer.to_string(next_number), 2, "0")}"
+    if MapSet.member?(existing_names, candidate),
+      do: find_available_name(base_name, existing_names, n + 1),
+      else: candidate
   end
 
   defp notify_of_affected_kafka_triggers(%{triggers: triggers}) do
diff --git a/test/lightning/workflows_test.exs b/test/lightning/workflows_test.exs
index ab5f9a0c54..aae13233fc 100644
--- a/test/lightning/workflows_test.exs
+++ b/test/lightning/workflows_test.exs
@@ -841,7 +841,7 @@ defmodule Lightning.WorkflowsTest do
       w1 = insert(:workflow, project: project, name: "Test Workflow")
 
       assert {:ok, %{workflow: workflow}} = Workflows.mark_for_deletion(w1, user)
-      assert workflow.name == "Test Workflow_del01"
+      assert workflow.name == "Test Workflow_del"
 
       # Test incrementing when deleting another workflow with the same name
       w2 = insert(:workflow, project: project, name: "Test Workflow")
@@ -849,7 +849,7 @@ defmodule Lightning.WorkflowsTest do
       assert {:ok, %{workflow: workflow2}} =
                Workflows.mark_for_deletion(w2, user)
 
-      assert workflow2.name == "Test Workflow_del02"
+      assert workflow2.name == "Test Workflow_del1"
 
       # Test incrementing again
       w3 = insert(:workflow, project: project, name: "Test Workflow")
@@ -857,7 +857,28 @@ defmodule Lightning.WorkflowsTest do
       assert {:ok, %{workflow: workflow3}} =
                Workflows.mark_for_deletion(w3, user)
 
-      assert workflow3.name == "Test Workflow_del03"
+      assert workflow3.name == "Test Workflow_del2"
+    end
+
+    test "mark_for_deletion/3 does not conflict with active workflows ending in _del" do
+      # An active workflow named "water_gap_analysis_del" (where _del is Delaware)
+      # should not interfere with deleting "water_gap_analysis"
+      project = insert(:project)
+      user = insert(:user)
+
+      # Active workflow with name ending in _del (not deleted)
+      _delaware_workflow =
+        insert(:workflow, project: project, name: "water_gap_analysis_del")
+
+      # Workflow to be deleted
+      w1 = insert(:workflow, project: project, name: "water_gap_analysis")
+
+      # Should still get _del suffix since the existing _del workflow is not deleted
+      assert {:ok, %{workflow: deleted}} = Workflows.mark_for_deletion(w1, user)
+      assert deleted.name == "water_gap_analysis_del1"
+
+      assert {:ok, %{workflow: deleted}} = Workflows.mark_for_deletion(w1, user)
+      assert deleted.name == "water_gap_analysis_del2"
     end
 
     test "allows reusing workflow name after marking for deletion, then validates error when using deleted workflow name" do
@@ -869,7 +890,7 @@ defmodule Lightning.WorkflowsTest do
       assert {:ok, %{workflow: deleted_workflow}} =
                Workflows.mark_for_deletion(w1, user)
 
-      assert deleted_workflow.name == "My Workflow_del01"
+      assert deleted_workflow.name == "My Workflow_del"
 
       # Should be able to create a new workflow with the original name
       assert {:ok, new_workflow} =
@@ -884,7 +905,7 @@ defmodule Lightning.WorkflowsTest do
       # Should NOT be able to create another workflow with the deleted workflow's name
       assert {:error, changeset} =
                Workflows.save_workflow(
-                 %{name: "My Workflow_del01", project_id: project.id},
+                 %{name: "My Workflow_del", project_id: project.id},
                  user
                )
 

From 039c8620051b3c571476c42c32ee4a206b698d37 Mon Sep 17 00:00:00 2001
From: Taylor Downs <taylor@openfn.org>
Date: Thu, 11 Dec 2025 14:00:48 +0100
Subject: [PATCH 7/7] what's in a name

---
 lib/lightning/workflows.ex | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/lightning/workflows.ex b/lib/lightning/workflows.ex
index 277076f749..1999c4e036 100644
--- a/lib/lightning/workflows.ex
+++ b/lib/lightning/workflows.ex
@@ -462,7 +462,7 @@ defmodule Lightning.Workflows do
         where: t.workflow_id == ^workflow.id
       )
 
-    new_name = append_del_to_name(workflow)
+    new_name = resolve_name_for_pending_deletion(workflow)
 
     Multi.new()
     |> Multi.update(
@@ -490,7 +490,10 @@ defmodule Lightning.Workflows do
     end)
   end
 
-  defp append_del_to_name(%Workflow{name: name, project_id: project_id}) do
+  defp resolve_name_for_pending_deletion(%Workflow{
+         name: name,
+         project_id: project_id
+       }) do
     base_name = "#{name}_del"
 
     existing_names =