fix: race condition in Retry function

[deblasis]

This PR introduces a test to repro the data race issue and also the fix for it in a separate commit.

Issue discovered in getsops/sops integration tests.
Related: getsops/sops#1226
Failed job: https://github.com/getsops/sops/actions/runs/18238383955/job/51962367579?pr=1226

How to Review

Step 1: Reproduce the Bug (Commit f38c967)

# Checkout the first commit (test only, no fix)
git checkout f38c967789

# Run test with race detector
cd common
go test -race -run TestRetry_RaceCondition

# Expected output (BUGGY):
# WARNING: DATA RACE
# Write at 0x... by goroutine X: retry.go:871
# Previous read at 0x... by goroutine Y: retry.go:907
# Found 1 data race(s)
# exit status 66
# FAIL

Step 2: Verify the Fix (Commit 7770835)

# Checkout the fix commit
git checkout 7770835982

# Run same test with race detector
cd common
go test -race -run TestRetry_RaceCondition

# Expected output (FIXED):
# PASS
# ok    github.com/oracle/oci-go-sdk/v65/common 1.020s
# ✅ No race detected!

Step 3: Run Full Test Suite

# Run all common package tests with race detector
go test -race ./common/ -v

# Run broader test suite
go test -race ./... -short

Problem Description

Root Cause

The Retry function had a data race when the context was cancelled:

// Line 807: Shared variable
var response OCIResponse
var err error

go func() {
    // Line 871: Goroutine WRITES to response
    response, err = operation(ctx, request, rsc, extraHeaders)
    // ...
}()

// Lines 905-910: RACE CONDITION
select {
case <-ctx.Done():
    // Line 907: Main thread READS response (concurrent access!)
    return response, ctx.Err()
case result := <-retrierChannel:
    return result.response, result.err
}

Impact

• Data Race: Undefined behavior per Go memory model
• Panic Risk: nil pointer dereference when accessing response fields
• Production Impact: Discovered in getsops/sops integration tests

Original Error

panic: runtime error: invalid memory address or nil pointer dereference
at github.com/oracle/oci-go-sdk/v65/common.newServiceFailureFromResponse
    common/errors.go:111

Solution

Changes Made

The fix ensures the retry goroutine checks for context cancellation and exits promptly:

1. Added context check before each retry attempt
2. Made sleep interruptible
3. Removed the racing select statement

Signed-off-by: Alessandro De Blasis [email protected]

[oracle-contributor-agreement]

Thank you for your pull request and welcome to our community! To contribute, please sign the Oracle Contributor Agreement (OCA).
The following contributors of this PR have not signed the OCA:

• PR author: [email protected] (@deblasis)

To sign the OCA, please create an Oracle account and sign the OCA in Oracle's Contributor Agreement Application.

When signing the OCA, please provide your GitHub username. After signing the OCA and getting an OCA approval from Oracle, this PR will be automatically updated.

If you are an Oracle employee, please make sure that you are a member of the main Oracle GitHub organization, and your membership in this organization is public.

[oracle-contributor-agreement]

Thank you for signing the OCA.