fix: add missing return after WriteErr in GetPods handler to prevent superfluous response write

[WorrierKhushal]

What type of PR is this?

/kind bug

What this PR does / why we need it:

In pkg/yurthub/otaupdate/ota.go, the GetPods HTTP handler calls
util.EncodePods(podList) and, on failure, correctly calls
util.WriteErr(w, "Encode pod list failed", http.StatusInternalServerError)
to write a 500 response — but was missing a return statement
immediately after.

Without the return, execution falls through to
util.WriteJSONResponse(w, data) with data == nil, which attempts to
call w.WriteHeader(http.StatusOK) (200) on a response that has already
been committed with a 500 status. This produces a Go HTTP warning
(http: superfluous response.WriteHeader call) and appends null to the
response body after the 500 error payload, corrupting the HTTP response
for any client hitting this error path.

Every other error branch in this same file (lines 70, 76, 85, 110, 115,
123, 131, 136, 145, 153) already follows the convention of
util.WriteErr(...) immediately followed by return — this single
branch was the only one missing it.

This PR adds the missing return statement and adds
TestGetPods_EncodePodsError to verify that on an encoding failure only
the 500 status is written and the handler returns cleanly.

Which issue(s) this PR fixes:

Fixes #2771

Special notes for your reviewer:

• go build ./pkg/yurthub/otaupdate/... — clean
• go vet ./pkg/yurthub/otaupdate/... — clean
• go test -v ./pkg/yurthub/otaupdate/... — all tests pass, including the new TestGetPods_EncodePodsError
• One-line change, zero risk of behavioral regression on the success path
• No exported function signatures changed

Does this PR introduce a user-facing change?

NONE

other Note

[codecov]

Codecov Report

❌ Patch coverage is 56.81818% with 38 lines in your changes missing coverage. Please review.
✅ Project coverage is 46.24%. Comparing base (ddf22f7) to head (52ac954).
⚠️ Report is 7 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/yurthub/util/dumpstack.go	0.00%	20 Missing ⚠️
pkg/yurthub/configuration/manager.go	33.33%	5 Missing and 1 partial ⚠️
pkg/yurthub/filter/manager/manager.go	89.36%	3 Missing and 2 partials ⚠️
...ub/proxy/multiplexer/testing/fake_filtermanager.go	0.00%	4 Missing ⚠️
cmd/yurthub/app/config/config.go	0.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2772      +/-   ##
==========================================
+ Coverage   46.20%   46.24%   +0.04%     
==========================================
  Files         405      405              
  Lines       27540    27633      +93     
==========================================
+ Hits        12724    12779      +55     
- Misses      13649    13676      +27     
- Partials     1167     1178      +11     

Flag	Coverage Δ
unittests	46.24% <56.81%> (+0.04%)	⬆️

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[WorrierKhushal]

Hi maintainers @zyjhtangtang @luc99hen sir
i just wanted to tell about my this pr :

• The Bug: In pkg/yurthub/otaupdate/ota.go, the GetPods handler was missing a return statement right after util.WriteErr(...) when EncodePods failed. This caused a fall-through to WriteJSONResponse, resulting in a Go HTTP warning (superfluous response.WriteHeader call) and response corruption.

• The Fix: Added the missing return statement (consistent with every other error branch in this file) and added a new unit test TestGetPods_EncodePodsError to prevent regressions.

Everything builds cleanly and all tests pass. Would love a quick review when you get a chance! Thanks!