[RanaPriyansh]

Which issue does this PR close?

• Closes GoogleCloudStorageBuilder with_skip_signature(true) still attempting to fetch credentials #520.

Rationale for this change

GCS upload requests fetched credentials and added a Bearer header even when with_skip_signature(true) was set. Request::send bypassed the existing skip-aware credential helper.

What changes are included in this PR?

Route upload requests through GoogleCloudStorageConfig::get_credential() and the optional Bearer-auth helper. Add a mock-server regression that checks credential calls and Authorization headers with signing enabled and disabled.

Are there any user-facing changes?

GCS uploads with skip_signature=true no longer fetch credentials at request time or send an Authorization header. The public API is unchanged.

Validation:

• The new regression failed on the upstream base: the skipped request called the credential provider, raising the count from 1 to 2.
• The focused regression passed after the repair.
• cargo test --features=aws,azure,gcp,http passed: 264 unit tests, 3 integration tests, 1 HTTP test, and 57 doctests. Six unit tests and two doctests were ignored.
• Strict Clippy passed for --features gcp and --no-default-features --features gcp-base. Formatting and diff checks passed.
• cargo test --features gcp had one unrelated doctest failure: a doctest imports Azure when the Azure feature is disabled. The doctest passed with the repository CI feature set above.

Live GCS and custom-connector behavior were not tested. Builder-time credential-file parsing is unchanged.

Codex used.

[alamb]

Marking as draft per #873 (comment) so i can find the PRs that need attention. Thank you

[alamb]

Reviewing this one per #873

[alamb]

@andrewhamon and @kylebarron -- any chance you are up for helping to review this PR?

[RanaPriyansh]

The test uses an explicit concrete Arc clone before conversion to the credential-provider trait object. This addresses the reported clone_on_ref_ptr finding while preserving the shared provider and existing assertions.

Formatting passed on the source committed as b9ea759. Local cargo test stopped during offline dependency resolution. The GCP regression and Clippy did not run locally. Hosted validation remains pending.

The prior emulator job failed while pulling the MinIO image, before its tests.

Codex used.

[kylebarron]

I've never used GCS nor anonymous auth on GCS, so I don't have a way to validate this PR myself

[RanaPriyansh]

The public-API regression passed locally on b9ea759: one test passed, with zero failures. It needs no GCS account.

The test uploads through put to a local HTTP server. With signing enabled, it asserts one credential-provider call and the received Bearer test-token header. With skip_signature=true, it asserts no additional credential call and no received Authorization header.

cargo test --features gcp --lib gcp::test::gcs_skip_signature_skips_credentials_and_authorization -- --exact --nocapture

Hosted Clippy also passed for this revision, including all targets. Live GCS anonymous uploads and bucket permissions remain untested.

Codex used.