prep release: v1.61.0

[lrlna]

Note

When approved, this PR will merge into the 1.61.0 branch which will — upon being approved itself — merge into main.

Things to review in this PR:

• Changelog correctness (There is a preview below, but it is not necessarily the most up to date. See the Files Changed for the true reality.)
• Version bumps
• That it targets the right release branch (1.61.0 in this case!).

---

🚀 Features

Query planner dry-run option (PR #6656)

This PR adds a new dry-run option to the Apollo-Expose-Query-Plan header value that emits the query plans back to Studio for visualizations. This new value will only emit the query plan, and abort execution. This can be helpful for tools like rover, where query plan generation is needed but not full runtime, or for potentially prewarming query plan caches out of band.

By @aaronArinder and @lennyburdette in #6656.

Enable Remote Proxy Downloads

This enables users without direct download access to specify a remote proxy mirror location for the github download of
the Apollo Router releases.

By @LongLiveCHIEF in #6667

🐛 Fixes

Header propagation rules passthrough (PR #6690)

Header propagation contains logic to prevent headers from being propagated more than once. This was broken
in #6281 which always considered a header propagated regardless if a rule
actually matched.

This PR alters the logic so that a header is marked as fixed only when it's populated.

The following will now work again:

headers:
  all:
    request:
      - propagate:
          named: a
          rename: b
      - propagate:
          named: b

Note that defaulting a header WILL populate it, so make sure to include your defaults last in your propagation
rules.

headers:
  all:
    request:
      - propagate:
          named: a
          rename: b
          default: defaulted # This will prevent any further rule evaluation for header `b`
      - propagate:
          named: b

Instead, make sure that your headers are defaulted last:

headers:
  all:
    request:
      - propagate:
          named: a
          rename: b
      - propagate:
          named: b
          default: defaulted # OK

By @BrynCooke in #6690

Entity cache: fix directive conflicts in cache-control header (Issue #6441)

Unnecessary cache-control directives are created in cache-control header. The router will now filter out unnecessary values from the cache-control header when the request resolves. So if there's max-age=10, no-cache, must-revalidate, no-store, the expected value for the cache-control header would simply be no-store. Please see the MDN docs for justification of this reasoning: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control#preventing_storing

By @bnjjj in #6543

Query Planning: fix __typename selections in sibling typename optimization

The query planner uses an optimization technique called "sibling typename", which attaches __typename selections to their sibling selections so the planner won't need to plan them separately.

Previously, when there were multiple identical selections and one of them has a __typename attached, the query planner could pick the one without the attachment, effectively losing a __typename selection.

Now, the query planner favors the one with a __typename attached without losing the __typename selection.

By @duckki in #6824

📃 Configuration

promote experimental_otlp_tracing_sampler from experimental (PR #6070)

The router's otlp tracing sampler feature that was previously experimental is now generally available.

If you used its experimental configuration, you should migrate to the new configuration option:

• telemetry.apollo.experimental_otlp_tracing_sampler is now telemetry.apollo.otlp_tracing_sampler

The experimental configuration option is now deprecated. It remains functional but will log warnings.

By @garypen in #6070

Remove experimental_ prefix for PQ local_manifests configuration

The experimental_local_manifests PQ configuration option is being promoted to stable. This change updates the configuration option name and any references to it, as well as the related documentation. The experimental_ usage remains valid as an alias for existing usages.

By @trevor-scheer in #6564

🛠 Maintenance

Reduce demand control allocations on start/reload (PR #6754)

When demand control is enabled, the router now preallocates capacity for demand control's processed schema and shrinks to fit after processing. When it's disabled, the router skips the type processing entirely to minimize startup impact.

By @tninesling in #6754

[svc-apollo-docs]

⚠️ Docs preview not attached to branch

The preview was not built because the PR's base branch 1.61.0 is not in the list of sources.

An Apollo team member can comment one of the following commands to dictate which branch to attach the preview to:

• !docs set-base-branch dev
• !docs set-base-branch 1.x

Build ID: 7ee4d09f7493a932f779ee38