Fix workflow migrations: remove redundant duplicates that break fresh-DB migrate

[IzBrain67]

Fixes #65.

Problem

On a clean setup the backend crash-loops on startup — manage.py migrate fails with:

django.db.utils.ProgrammingError: column "workflow_context" of relation "flow_projects" already exists

This blocks every fresh environment (new clone, CI, docker compose down -v reset, a new contributor's first run). Databases that were already migrated are unaffected, which is why it went unnoticed on main.

Root cause

The migration set is internally inconsistent. 0001_initial was regenerated into a full snapshot in commit 8d9fdb23 ("Track Django migrations and stop auto-generation") — it already creates FlowProject.workflow_context and the WorkflowRun model. After that, main was a consistent 3-migration chain.

PR #55 (98af506a) then added a parallel branch of locally auto-generated migrations on top of that snapshot:

Migration	Operation	Already done by
0002_flowproject_workflow_context	AddField workflow_context	0001_initial
0003_workflowrun	CreateModel WorkflowRun	0001_initial
0004_flowproject_hpc_target_flowproject_reference_and_more	AddField hpc_target, reference, visibility	0002_flowproject_visibility + 0003_flowproject_reference_hpc_target
0005_merge_20260524_1609	(empty merge)	—

98af506a does not change models.py, so these are not migrations for a new model change — they are duplicates of what the snapshot already builds (the 0005_merge is a leftover makemigrations --merge artifact). Startup runs migrate only, so the redundant ops execute against the schema 0001_initial already created → DuplicateColumn.

Fix

Delete the 4 redundant migrations, leaving the consistent chain:

0001_initial → 0002_flowproject_visibility → 0003_flowproject_reference_hpc_target

which reproduces the current models.py schema exactly (workflow_context, visibility, reference, hpc_target, WorkflowRun); 0003_flowproject_reference_hpc_target already uses ADD COLUMN IF NOT EXISTS.

No data migration is needed: on databases that already applied the redundant migrations the deleted records become harmless phantom entries, and migrate resolves the remaining single-leaf graph without error.

Verification

Ran migrate against a brand-new empty database with this branch's code:

Applying workflow.0001_initial... OK
Applying workflow.0002_flowproject_visibility... OK
Applying workflow.0003_flowproject_reference_hpc_target... OK

No DuplicateColumn, no crash loop. (Before this change, the same fresh-DB migrate fails at 0002_flowproject_workflow_context.)

Notes / follow-ups

• The box app has an analogous redundancy (0002–0005 alter_pythonfile_category), but those are AlterField ops that don't break migrate — left out of scope here as a follow-up cleanup.
• Prevention: the repo has no CI. Since pytest/pytest-django builds its test DB by running migrations, a minimal CI job running the backend test suite against a fresh Postgres would catch this class of bug automatically. Recommended as a separate task.

[Copilot]

Pull request overview

Removes a redundant/duplicated branch of Django migrations in the workflow app that caused manage.py migrate to fail on a fresh database due to duplicate schema operations (e.g., workflow_context already existing), restoring a single consistent migration chain.

Changes:

• Deleted duplicate workflow migrations that re-applied schema already created by 0001_initial.
• Removed an empty merge migration that only existed to reconcile the duplicated migration branches.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
gui/workflow_backend/django-project/app/workflow/migrations/0002_flowproject_workflow_context.py	Deleted redundant migration that re-added FlowProject.workflow_context already present in 0001_initial.
gui/workflow_backend/django-project/app/workflow/migrations/0003_workflowrun.py	Deleted redundant migration that re-created WorkflowRun already present in 0001_initial.
gui/workflow_backend/django-project/app/workflow/migrations/0004_flowproject_hpc_target_flowproject_reference_and_more.py	Deleted redundant migration that re-added fields already covered by the remaining migration chain.
gui/workflow_backend/django-project/app/workflow/migrations/0005_merge_20260524_1609.py	Deleted empty merge migration that only existed due to the duplicated branch.

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