[Breaking change]: Remove NUGET_ENABLE_ENHANCED_HTTP_RETRY from NuGet, removing the ability to disable exponential retry

[nkolev92]

Description

Starting 6.0.300, NuGet introduced exponential retry back-off for failed http calls.

Sometimes restores would overwhelm servers and wouldn't be able to handle all package requests. Exponential retry allowed these requests to succeed.

Given that it's been a default for nearly 4 years and we have not received any feedback with issues, it is safe to remove this fallback.

Version

.NET 10 Preview 6

Previous behavior

NUGET_ENABLE_ENHANCED_HTTP_RETRY being set to false would go back to the old 200ms delay between calls.

New behavior

NUGET_ENABLE_ENHANCED_HTTP_RETRY does nothing.

Type of breaking change

• Binary incompatible: Existing binaries might encounter a breaking change in behavior, such as failure to load or execute, and if so, require recompilation.
• Source incompatible: When recompiled using the new SDK or component or to target the new runtime, existing source code might require source changes to compile successfully.
• Behavioral change: Existing binaries might behave differently at run time.

Reason for change

The fallback has outlived it's utility.

Recommended action

No action required.

Feature area

Other (please put exact area in description textbox)

Affected APIs

N/A