Feat(utils): psql unique index instead of constraint (#6386)

**What**
- always return an index expression, also for unique constraints

**why**
- constraints can't be partial, meaning `UNIQUE ... WHERE` is not possible with constraints
- constraints are indicies under the hood so it doesn't change the behavior of the system when we're not using constraint specific features but just using them for `UNIQUE`

.changeset/hot-coins-itch.md

@@ -0,0 +1,5 @@
+---
+"@medusajs/utils": patch
+---
+
+feat(utils): make psql index util return index instead of constraint for unique indicies becuase partial constraints don't exist :'(

packages/utils/src/common/__tests__/create-psql-index-helper.ts

@@ -73,9 +73,9 @@ describe("createPsqlIndexStatementHelper", function () {
 
     const indexStatement = createPsqlIndexStatementHelper(options)
     expect(indexStatement).toEqual(
-      `ALTER TABLE IF EXISTS "${options.tableName}" ADD CONSTRAINT "${
-        options.name
-      }" UNIQUE (${options.columns.join(", ")}) WHERE ${options.where}`
+      `CREATE UNIQUE INDEX IF NOT EXISTS "${options.name}" ON "${
+        options.tableName
+      }" (${options.columns.join(", ")}) WHERE ${options.where}`
     )
   })
 })

packages/utils/src/common/create-psql-index-helper.ts

@@ -45,10 +45,7 @@ export function createPsqlIndexStatementHelper({
   columns = Array.isArray(columns) ? columns.join(", ") : columns
   const typeStr = type ? ` USING ${type}` : ""
   const optionsStr = where ? ` WHERE ${where}` : ""
+  const uniqueStr = unique ? "UNIQUE " : ""
 
-  if (!unique) {
-    return `CREATE INDEX IF NOT EXISTS "${name}" ON "${tableName}"${typeStr} (${columns})${optionsStr}`
-  } else {
-    return `ALTER TABLE IF EXISTS "${tableName}" ADD CONSTRAINT "${name}" UNIQUE (${columns})${optionsStr}`
-  }
+  return `CREATE ${uniqueStr}INDEX IF NOT EXISTS "${name}" ON "${tableName}"${typeStr} (${columns})${optionsStr}`
 }