Add solution for gin challenge-3-validation-errors by yogtanko

[yogtanko]

gin challenge-3-validation-errors Solution

Submitted by: @yogtanko
Package: gin
Challenge: challenge-3-validation-errors

Description

This PR contains my solution for gin challenge-3-validation-errors.

Changes

• Added solution file to packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go

Testing

• Solution passes all test cases
• Code follows Go best practices

Thank you for reviewing my submission! 🚀

[coderabbitai]

Walkthrough

Adds a Gin-based HTTP service providing in-memory product and category models, field and cross-field validation, sanitization, endpoints for single/bulk creation and validation checks, a validation-rules endpoint, and server startup on :8080.

Changes

Product & Category API with Validation

Layer / File(s)	Summary
Data Types & Validation Contracts packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go	Product, Category, Image, and Inventory types are defined with JSON tags and binding constraints. ValidationError and APIResponse provide structured error and response envelopes.
Validation Helpers & Core Logic packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go	In-memory product/category stores with sync.RWMutex, SKU/slug/currency/warehouse validators, validateProduct for field and cross-field checks, and sanitizeProduct for normalization and inventory computation.
Product Creation packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go	createProduct binds, validates, sanitizes, assigns an ID, and persists a product. createProductsBulk validates items independently, returns per-index results, persists valid items with incrementing IDs, and returns summary counts.
Category & Validation Endpoints packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go	createCategory enforces slug format and case-insensitive name uniqueness under a write lock. validateSKUEndpoint checks SKU format/duplication. validateProductEndpoint validates payloads without saving.
Rules Endpoint & Server Setup packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go	getValidationRules returns supported currencies and warehouse codes. setupRouter wires routes and main starts the Gin server on :8080.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• RezaSi/go-interview-practice#662: Implements the same Gin “challenge-3-validation-errors” solution with matching models and endpoints.
• RezaSi/go-interview-practice#1499: Contains a highly similar Gin-based implementation of the same challenge, sharing validators and handler structure.

Poem

🐰 In a meadow of JSON and code I hop,
I trim the strings and make stray spaces stop,
I validate SKUs and counts with care,
I stamp timestamps and store them there,
Hopping off—products neat, tidy, and top!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: adding a solution file for a specific gin challenge by a named author.
Description check	✅ Passed	The description is clearly related to the changeset, explaining the challenge submission, file location, and validation checks performed.
Docstring Coverage	✅ Passed	Docstring coverage is 86.67% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 golangci-lint (2.12.2)

level=error msg="[linters_context] typechecking error: pattern ./...: directory prefix . does not contain main module or its selected dependencies"

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[coderabbitai]

Actionable comments posted: 4

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 89300fce-03da-4b40-b9a5-3871abb87189

📥 Commits

Reviewing files that changed from the base of the PR and between aa037e3 and fd0f48f.

📒 Files selected for processing (1)

• packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go

[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (2)

packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go (2)

157-164: ⚠️ Potential issue | 🟠 Major | ⚡ Quick win

SKU uniqueness is still not enforced at write time.

validateProduct checks SKU format only, and both create paths append without an atomic uniqueness guard. Concurrent requests can persist duplicate SKUs.

Suggested fix

 func createProduct(c *gin.Context) {
@@
 	sanitizeProduct(&product)
-    mu.Lock()
-    defer mu.Unlock()
+	mu.Lock()
+	for _, existing := range products {
+		if strings.EqualFold(existing.SKU, product.SKU) {
+			mu.Unlock()
+			c.JSON(http.StatusBadRequest, APIResponse{
+				Success: false,
+				Message: "sku already exists",
+			})
+			return
+		}
+	}
 	product.ID = nextProductID
 	nextProductID++
 	products = append(products, product)
+	mu.Unlock()

 	c.JSON(201, APIResponse{
@@
 	for i, product := range inputProducts {
@@
 		} else {
 			sanitizeProduct(&product)
 			mu.Lock()
+			duplicate := false
+			for _, existing := range products {
+				if strings.EqualFold(existing.SKU, product.SKU) {
+					duplicate = true
+					break
+				}
+			}
+			if duplicate {
+				mu.Unlock()
+				results = append(results, BulkResult{
+					Index:   i,
+					Success: false,
+					Errors: []ValidationError{{
+						Field:   "sku",
+						Message: "sku already exists",
+					}},
+				})
+				continue
+			}
 			product.ID = nextProductID
 			nextProductID++
 			products = append(products, product)
 			mu.Unlock()

Also applies to: 251-256, 299-303

---

118-120: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Category validation is case-sensitive and inconsistent with category creation rules.

isValidCategory uses exact match, while category uniqueness uses strings.EqualFold. This can reject otherwise valid category names by casing alone.

Suggested fix

-	for _, cur := range categories {
-		if cur.Name == categoryName {
+	for _, cur := range categories {
+		if strings.EqualFold(cur.Name, categoryName) {
 			return true
 		}
 	}

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 39ff678e-148d-4b61-a375-63086fa912b0

📥 Commits

Reviewing files that changed from the base of the PR and between fd0f48f and f2091c3.

📒 Files selected for processing (1)

• packages/gin/challenge-3-validation-errors/submissions/yogtanko/solution.go

[github-actions]

🎉 Auto-merged!

This PR was automatically merged after 2 days with all checks passing.

Thank you for your contribution, @yogtanko!

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