[Go] defer file close

[wing328]

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---

Summary by cubic

Fixes multipart file uploads in generated Go clients by closing the file after copying to the form part, preventing read-on-closed-file errors and ensuring proper resource cleanup.

• Bug Fixes
  • Update addFile to create the form part, copy file contents, then close the file.
  • Regenerate Go sample clients to include the fix.

^{Written for commit 6ca94d0. Summary will update automatically on new commits.}

[cubic-dev-ai]

9 issues found across 9 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="samples/openapi3/client/petstore/go/go-petstore/client.go">

<violation number="1" location="samples/openapi3/client/petstore/go/go-petstore/client.go:541">
P2: Resource leak: if `CreateFormFile` or `io.Copy` fails, the file handle is never closed. Use `defer file.Close()` immediately after opening the file to ensure cleanup in all error paths.</violation>
</file>

<file name="modules/openapi-generator/src/main/resources/go/client.mustache">

<violation number="1" location="modules/openapi-generator/src/main/resources/go/client.mustache:606">
P2: File descriptor leak on error paths. If `CreateFormFile` or `io.Copy` fails, the function returns without closing the file. Use `defer file.Close()` immediately after opening the file to ensure proper cleanup regardless of how the function exits.</violation>
</file>

<file name="samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/client.go">

<violation number="1" location="samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/client.go:491">
P2: File handle leak on error paths. If `CreateFormFile` or `io.Copy` fails, the function returns without closing the file. Use `defer file.Close()` immediately after opening the file to ensure proper cleanup in all code paths.</violation>
</file>

<file name="samples/client/echo_api/go-external-refs/client.go">

<violation number="1" location="samples/client/echo_api/go-external-refs/client.go:517">
P2: File handle may leak if `CreateFormFile` or `io.Copy` fails before `file.Close()` is reached. Use `defer file.Close()` immediately after the successful `os.Open()` to ensure the file is always closed regardless of error paths.</violation>
</file>

<file name="samples/openapi3/client/petstore/go-petstore-withXml/client.go">

<violation number="1" location="samples/openapi3/client/petstore/go-petstore-withXml/client.go:513">
P2: File handle will leak if `CreateFormFile` or `io.Copy` fails. Use `defer file.Close()` immediately after opening the file to ensure proper cleanup in all error paths.</violation>
</file>

<file name="samples/openapi3/client/petstore/go/go-petstore-aws-signature/client.go">

<violation number="1" location="samples/openapi3/client/petstore/go/go-petstore-aws-signature/client.go:545">
P2: File handle leak: if `CreateFormFile` or `io.Copy` fails, the function returns early without closing the opened file. Use `defer file.Close()` immediately after `os.Open()` to ensure the file is always closed.</violation>
</file>

<file name="samples/client/echo_api/go/client.go">

<violation number="1" location="samples/client/echo_api/go/client.go:517">
P2: File handle leaks if `CreateFormFile` or `io.Copy` fails. Add `defer file.Close()` immediately after opening the file to ensure the file is closed on all error paths. This is the idiomatic Go pattern for resource cleanup.</violation>
</file>

<file name="samples/client/petstore/go/go-petstore/client.go">

<violation number="1" location="samples/client/petstore/go/go-petstore/client.go:523">
P2: Resource leak: if `CreateFormFile` or `io.Copy` fails, the file handle is never closed. Use `defer file.Close()` immediately after opening the file to ensure cleanup on all error paths.</violation>
</file>

<file name="samples/openapi3/client/petstore/go-petstore-generateMarshalJSON-false/client.go">

<violation number="1" location="samples/openapi3/client/petstore/go-petstore-generateMarshalJSON-false/client.go:513">
P2: File resource leak on error paths. If `CreateFormFile` or `io.Copy` fails, the file handle is never closed. Use `defer file.Close()` immediately after opening the file to ensure cleanup on all code paths.</violation>
</file>

_{Reply to cubic to teach it or ask questions. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: Resource leak: if CreateFormFile or io.Copy fails, the file handle is never closed. Use defer file.Close() immediately after opening the file to ensure cleanup on all error paths.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/client/petstore/go/go-petstore/client.go, line 523:

<comment>Resource leak: if `CreateFormFile` or `io.Copy` fails, the file handle is never closed. Use `defer file.Close()` immediately after opening the file to ensure cleanup on all error paths.</comment>

<file context>
@@ -519,17 +519,18 @@ func addFile(w *multipart.Writer, fieldName, path string) error {
 	}
-	err = file.Close()
+
+	part, err := w.CreateFormFile(fieldName, filepath.Base(path))
 	if err != nil {
 		return err
</file context>