SSR RPC cache: no replacement fill after the lookup's deadline

[feruzm]

Follow-up to #73 (refs #72). One commit that answered the last review thread on #73 landed on the branch after the PR had already merged, so it never shipped.

What

A coalesced reader whose queued fill was rejected retries only while its own lookup deadline has not passed; past it the lookup answers timeout and starts no replacement fill, so nothing is created for a reader that has already given up (previously the retry could start a fill after the deadline, which then consumed fill capacity and called Hive for nobody).

Tests

Suite at this commit: 152 passing (same as the merged head plus no new tests; the change narrows an existing retry path).

Summary by CodeRabbit

• Bug Fixes
  • Improved lookup reliability by limiting retries to the available time budget.
  • Added clearer timeout handling when a lookup cannot complete within the allowed time.

[qodo-free-for-open-source-projects]

PR Summary by Qodo

SSR RPC cache: prevent replacement fills after lookup deadline

🐞 Bug fix 🕐 10-20 Minutes

AI Description

• Stop retrying coalesced cache lookups once the caller’s deadline has passed.
• Treat late fill rejections as timeouts, avoiding replacement fills with no waiting readers.

Diagram

graph TD
  A["SsrRpc.Resolve()"] --> B{"Cache hit?"} --> C["Return cached"]
  B -->|"Miss"| D["InFlight pending"] --> E["Wait until deadline"] --> F{"Fill rejected?"} --> G["Retry (if before deadline)"]
  F -->|"Rejected after deadline"| H["Return timeout (no replacement fill)"]
  D --> I["Fill() worker"] --> J["Hive RPC"] --> K["Populate cache"]

Loading

High-Level Assessment

The following are alternative approaches to this PR:

1. Propagate CancellationToken/deadline to fill scheduling

• ➕ Makes deadline semantics explicit (no TickCount comparisons)
• ➕ Can stop or avoid queued work earlier with cooperative cancellation
• ➖ More invasive: requires plumbing tokens through coalescing/fill layers
• ➖ Riskier behavior change (fills currently run to completion to warm cache)

2. Track per-pending “earliest waiter deadline”

• ➕ Lets the system decide whether a replacement fill still has any interested readers
• ➕ Avoids per-reader retry logic in Resolve()
• ➖ Additional state and synchronization on Pending
• ➖ More complexity for a narrowly-scoped edge case

Recommendation: The PR’s approach is the best fit for this follow-up: it minimally constrains the existing single-retry path by the reader’s own deadline, and cleanly maps late FillRejectedException to an immediate timeout. Alternatives add complexity and broader semantic changes without clear additional benefit for this specific regression.

Files changed (1) +8 / -2

Bug fix (1) +8 / -2

SsrRpc.csGate coalesced retry on deadline; treat late fill rejections as timeouts +8/-2

Gate coalesced retry on deadline; treat late fill rejections as timeouts

• Tightens the FillRejectedException retry condition so a coalesced reader only retries before its lookup deadline. Adds a fallback FillRejectedException handler for coalesced readers to return Outcome.Timeout (and increment timeout counters) when the deadline is already exceeded, preventing replacement fills from being started after the caller has given up.

dotnet/EcencyApi/Handlers/SsrRpc.cs

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 39f7938c8a

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[chatgpt-codex-connector]

Keep pre-deadline repeat rejections unavailable

When a reader retries after coalescing onto one rejected fill and then coalesces onto another fill that is rejected immediately because the queue is full, retried is already true, so this catch returns Timeout/HTTP 504 even though the lookup deadline has not elapsed. This is possible during the queue-saturation scenario that produces FillRejectedException("fill queue full"); the second catch should be restricted to an expired deadline so a repeat rejection before the deadline retains the existing Unavailable/502 result and error accounting.

Useful? React with 👍 / 👎.

[feruzm]

Fixed in 8a6cb09: only a rejection past the lookup's deadline is reported as a timeout; a repeat rejection before it (the queue full twice) falls through to the unavailable result with its error accounting, as before.

[qodo-code-review]

Code Review by Qodo

🐞 Bugs (0) 📘 Rule violations (0) 📎 Requirement gaps (0) 🎨 UX issues (0) 🔗 Cross-repo conflicts (0) 📜 Skill insights (0)

1. Queue-full misreported timeout ✓ Resolved 🐞 Bug ≡ Correctness

Description

Resolve() now maps any coalesced FillRejectedException to Outcome.Timeout (HTTP 504) even when
the fill was rejected due to internal overload (e.g., "fill queue full"), misclassifying the failure
and incrementing the Timeout counter instead of Error/overload. This can mislead clients/monitoring
by reporting "Upstream Timeout" for a local capacity issue and can change behavior compared to the
previous 502 path.

Code

dotnet/EcencyApi/Handlers/SsrRpc.cs[R281-285]

+        catch (FillRejectedException) when (coalesced)
+        {
+            Interlocked.Increment(ref counter.Timeout);
+            return new Resolution(Outcome.Timeout, Array.Empty<byte>(), "budget exceeded");
+        }

Relevance

●● Moderate

Accepted history supports timeout for expired coalesced fills, but lacks precedent distinguishing
queue saturation from budget expiry.

PR-#73

ⓘ Recommendations generated based on similar findings in past PRs

Evidence

The new catch block unconditionally converts coalesced FillRejectedException into a timeout, but
FillRejectedException is thrown not only for budget expiry but also for internal queue saturation.
Since Outcome.Timeout is mapped to HTTP 504 with an "Upstream Timeout" body, this change
misreports internal overload as upstream timeout and skews the Timeout counter.

dotnet/EcencyApi/Handlers/SsrRpc.cs[271-285]
dotnet/EcencyApi/Handlers/SsrRpc.cs[328-343]
dotnet/EcencyApi/Handlers/SsrRpc.cs[411-416]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`Resolve()` now catches `FillRejectedException` for coalesced readers and always returns `Outcome.Timeout` with `"budget exceeded"`. But `FillRejectedException` is also thrown for internal overload (`"fill queue full"`), which should not be reported as an upstream timeout (HTTP 504) and should not increment the Timeout counter.
### Issue Context
- `Fill()` can throw `FillRejectedException("fill queue full")` when the local fill queue limit is exceeded.
- `Rpc()` maps `Outcome.Timeout` to HTTP 504 + `{ "error": "Upstream Timeout" }`, which is inaccurate for local queue saturation.
### Fix Focus Areas
- dotnet/EcencyApi/Handlers/SsrRpc.cs[271-295]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[399-416]
### Suggested fix
1. Make `FillRejectedException` carry a typed reason (e.g., `enum FillRejectReason { ExpiredInQueue, QueueFull }`), or introduce two distinct exception types.
2. In `Resolve()`:
- Keep the "retry once" path for `ExpiredInQueue` (only while `TickCount64 < deadline`).
- If the rejection is `QueueFull`, return a non-timeout outcome (e.g., `Outcome.Unavailable` or a new `Outcome.Overloaded`) and increment an appropriate counter (likely `Error` or a new `Overload`).
- For `ExpiredInQueue` after the deadline, return `Outcome.Timeout`.
3. Ensure the HTTP mapping matches the outcome (avoid returning 504/"Upstream Timeout" for local overload).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

2. Overbroad FillRejected timeout ✓ Resolved 🐞 Bug ≡ Correctness

Description

Resolve() now catches any FillRejectedException for coalesced readers and returns
Outcome.Timeout, even if the reader’s lookup deadline has not passed (e.g., a second rejection
after retry, or a quick “fill queue full”). This misclassifies internal capacity/errors as timeouts
and can make two concurrent callers of the same key observe different outcomes/status codes for the
same underlying failure.

Code

dotnet/EcencyApi/Handlers/SsrRpc.cs[R281-284]

+        catch (FillRejectedException) when (coalesced)
+        {
+            Interlocked.Increment(ref counter.Timeout);
+            return new Resolution(Outcome.Timeout, Array.Empty<byte>(), "budget exceeded");

Evidence

The new catch unconditionally maps all coalesced FillRejectedException to timeout, regardless of
deadline, but FillRejectedException can be thrown immediately for capacity reasons (“fill queue
full”), not just after a reader’s budget is exhausted. Also, retried is only used to allow one
retry; a second rejection while still before deadline will now be treated as a timeout because the
broad coalesced catch has no deadline guard.

dotnet/EcencyApi/Handlers/SsrRpc.cs[218-285]
dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`Resolve()` added `catch (FillRejectedException) when (coalesced)` which always maps fill rejection to `Outcome.Timeout` and increments `counter.Timeout`. This is broader than the PR intent (“past the lookup deadline, answer timeout and start no replacement fill”) and can:
- return 504 Timeout even when the lookup deadline has **not** passed (e.g., on a second `FillRejectedException` after the single retry)
- mask non-timeout rejection causes such as `"fill queue full"`
### Issue Context
`FillRejectedException` is thrown for at least two distinct reasons: queue capacity (`"fill queue full"`) and expiry (`"fill expired in queue"`). Only the post-deadline case should be forced into a timeout response per the PR description; otherwise preserve the original behavior (surface as `Unavailable` with the underlying message) or retry while budget remains.
### Fix Focus Areas
- dotnet/EcencyApi/Handlers/SsrRpc.cs[266-295]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]
### Suggested change
Narrow the new catch so it only returns `Outcome.Timeout` when the deadline has passed (e.g., `when (coalesced && Environment.TickCount64 >= deadline)`), and let other `FillRejectedException` cases fall through to the existing general exception handler (or handle them explicitly with `Outcome.Unavailable` and `e.Message`).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

3. Queue-full misreported timeout ✓ Resolved 🐞 Bug ≡ Correctness

Description

Resolve() now maps any coalesced FillRejectedException to Outcome.Timeout (HTTP 504) even when
the fill was rejected due to internal overload (e.g., "fill queue full"), misclassifying the failure
and incrementing the Timeout counter instead of Error/overload. This can mislead clients/monitoring
by reporting "Upstream Timeout" for a local capacity issue and can change behavior compared to the
previous 502 path.

Code

dotnet/EcencyApi/Handlers/SsrRpc.cs[R281-285]

+        catch (FillRejectedException) when (coalesced)
+        {
+            Interlocked.Increment(ref counter.Timeout);
+            return new Resolution(Outcome.Timeout, Array.Empty<byte>(), "budget exceeded");
+        }

Relevance

●● Moderate

Accepted history supports timeout for expired coalesced fills, but lacks precedent distinguishing
queue saturation from budget expiry.

PR-#73

ⓘ Recommendations generated based on similar findings in past PRs

Evidence

The new catch block unconditionally converts coalesced FillRejectedException into a timeout, but
FillRejectedException is thrown not only for budget expiry but also for internal queue saturation.
Since Outcome.Timeout is mapped to HTTP 504 with an "Upstream Timeout" body, this change
misreports internal overload as upstream timeout and skews the Timeout counter.

dotnet/EcencyApi/Handlers/SsrRpc.cs[271-285]
dotnet/EcencyApi/Handlers/SsrRpc.cs[328-343]
dotnet/EcencyApi/Handlers/SsrRpc.cs[411-416]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`Resolve()` now catches `FillRejectedException` for coalesced readers and always returns `Outcome.Timeout` with `"budget exceeded"`. But `FillRejectedException` is also thrown for internal overload (`"fill queue full"`), which should not be reported as an upstream timeout (HTTP 504) and should not increment the Timeout counter.
### Issue Context
- `Fill()` can throw `FillRejectedException("fill queue full")` when the local fill queue limit is exceeded.
- `Rpc()` maps `Outcome.Timeout` to HTTP 504 + `{ "error": "Upstream Timeout" }`, which is inaccurate for local queue saturation.
### Fix Focus Areas
- dotnet/EcencyApi/Handlers/SsrRpc.cs[271-295]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[399-416]
### Suggested fix
1. Make `FillRejectedException` carry a typed reason (e.g., `enum FillRejectReason { ExpiredInQueue, QueueFull }`), or introduce two distinct exception types.
2. In `Resolve()`:
- Keep the "retry once" path for `ExpiredInQueue` (only while `TickCount64 < deadline`).
- If the rejection is `QueueFull`, return a non-timeout outcome (e.g., `Outcome.Unavailable` or a new `Outcome.Overloaded`) and increment an appropriate counter (likely `Error` or a new `Overload`).
- For `ExpiredInQueue` after the deadline, return `Outcome.Timeout`.
3. Ensure the HTTP mapping matches the outcome (avoid returning 504/"Upstream Timeout" for local overload).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

View medium (2)

4. Overbroad FillRejected timeout ✓ Resolved 🐞 Bug ≡ Correctness

Description

Resolve() now catches any FillRejectedException for coalesced readers and returns
Outcome.Timeout, even if the reader’s lookup deadline has not passed (e.g., a second rejection
after retry, or a quick “fill queue full”). This misclassifies internal capacity/errors as timeouts
and can make two concurrent callers of the same key observe different outcomes/status codes for the
same underlying failure.

Code

dotnet/EcencyApi/Handlers/SsrRpc.cs[R281-284]

+        catch (FillRejectedException) when (coalesced)
+        {
+            Interlocked.Increment(ref counter.Timeout);
+            return new Resolution(Outcome.Timeout, Array.Empty<byte>(), "budget exceeded");

Evidence

The new catch unconditionally maps all coalesced FillRejectedException to timeout, regardless of
deadline, but FillRejectedException can be thrown immediately for capacity reasons (“fill queue
full”), not just after a reader’s budget is exhausted. Also, retried is only used to allow one
retry; a second rejection while still before deadline will now be treated as a timeout because the
broad coalesced catch has no deadline guard.

dotnet/EcencyApi/Handlers/SsrRpc.cs[218-285]
dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`Resolve()` added `catch (FillRejectedException) when (coalesced)` which always maps fill rejection to `Outcome.Timeout` and increments `counter.Timeout`. This is broader than the PR intent (“past the lookup deadline, answer timeout and start no replacement fill”) and can:
- return 504 Timeout even when the lookup deadline has **not** passed (e.g., on a second `FillRejectedException` after the single retry)
- mask non-timeout rejection causes such as `"fill queue full"`
### Issue Context
`FillRejectedException` is thrown for at least two distinct reasons: queue capacity (`"fill queue full"`) and expiry (`"fill expired in queue"`). Only the post-deadline case should be forced into a timeout response per the PR description; otherwise preserve the original behavior (surface as `Unavailable` with the underlying message) or retry while budget remains.
### Fix Focus Areas
- dotnet/EcencyApi/Handlers/SsrRpc.cs[266-295]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]
### Suggested change
Narrow the new catch so it only returns `Outcome.Timeout` when the deadline has passed (e.g., `when (coalesced && Environment.TickCount64 >= deadline)`), and let other `FillRejectedException` cases fall through to the existing general exception handler (or handle them explicitly with `Outcome.Unavailable` and `e.Message`).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

5. Queue-full misreported timeout ✓ Resolved 🐞 Bug ≡ Correctness

Description

Resolve() now maps any coalesced FillRejectedException to Outcome.Timeout (HTTP 504) even when
the fill was rejected due to internal overload (e.g., "fill queue full"), misclassifying the failure
and incrementing the Timeout counter instead of Error/overload. This can mislead clients/monitoring
by reporting "Upstream Timeout" for a local capacity issue and can change behavior compared to the
previous 502 path.

Code

dotnet/EcencyApi/Handlers/SsrRpc.cs[R281-285]

+        catch (FillRejectedException) when (coalesced)
+        {
+            Interlocked.Increment(ref counter.Timeout);
+            return new Resolution(Outcome.Timeout, Array.Empty<byte>(), "budget exceeded");
+        }

Relevance

●● Moderate

Accepted history supports timeout for expired coalesced fills, but lacks precedent distinguishing
queue saturation from budget expiry.

PR-#73

ⓘ Recommendations generated based on similar findings in past PRs

Evidence

The new catch block unconditionally converts coalesced FillRejectedException into a timeout, but
FillRejectedException is thrown not only for budget expiry but also for internal queue saturation.
Since Outcome.Timeout is mapped to HTTP 504 with an "Upstream Timeout" body, this change
misreports internal overload as upstream timeout and skews the Timeout counter.

dotnet/EcencyApi/Handlers/SsrRpc.cs[271-285]
dotnet/EcencyApi/Handlers/SsrRpc.cs[328-343]
dotnet/EcencyApi/Handlers/SsrRpc.cs[411-416]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`Resolve()` now catches `FillRejectedException` for coalesced readers and always returns `Outcome.Timeout` with `"budget exceeded"`. But `FillRejectedException` is also thrown for internal overload (`"fill queue full"`), which should not be reported as an upstream timeout (HTTP 504) and should not increment the Timeout counter.
### Issue Context
- `Fill()` can throw `FillRejectedException("fill queue full")` when the local fill queue limit is exceeded.
- `Rpc()` maps `Outcome.Timeout` to HTTP 504 + `{ "error": "Upstream Timeout" }`, which is inaccurate for local queue saturation.
### Fix Focus Areas
- dotnet/EcencyApi/Handlers/SsrRpc.cs[271-295]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[399-416]
### Suggested fix
1. Make `FillRejectedException` carry a typed reason (e.g., `enum FillRejectReason { ExpiredInQueue, QueueFull }`), or introduce two distinct exception types.
2. In `Resolve()`:
- Keep the "retry once" path for `ExpiredInQueue` (only while `TickCount64 < deadline`).
- If the rejection is `QueueFull`, return a non-timeout outcome (e.g., `Outcome.Unavailable` or a new `Outcome.Overloaded`) and increment an appropriate counter (likely `Error` or a new `Overload`).
- For `ExpiredInQueue` after the deadline, return `Outcome.Timeout`.
3. Ensure the HTTP mapping matches the outcome (avoid returning 504/"Upstream Timeout" for local overload).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

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💡 Did you know, you can tweak Display preferences with a live preview to see your comment before it ships

More tips ↗ | Customize Qodo ↗ | Qodo docs ↗

[qodo-free-for-open-source-projects]

Code Review by Qodo

🐞 Bugs (2) 📘 Rule violations (0) 📎 Requirement gaps (0) 📜 Skill insights (0)

1. Overbroad FillRejected timeout 🐞 Bug ≡ Correctness ⭐ New

Description

Resolve() now catches any FillRejectedException for coalesced readers and returns
Outcome.Timeout, even if the reader’s lookup deadline has not passed (e.g., a second rejection
after retry, or a quick “fill queue full”). This misclassifies internal capacity/errors as timeouts
and can make two concurrent callers of the same key observe different outcomes/status codes for the
same underlying failure.

Code

dotnet/EcencyApi/Handlers/SsrRpc.cs[R281-284]

+        catch (FillRejectedException) when (coalesced)
+        {
+            Interlocked.Increment(ref counter.Timeout);
+            return new Resolution(Outcome.Timeout, Array.Empty<byte>(), "budget exceeded");

Evidence

The new catch unconditionally maps all coalesced FillRejectedException to timeout, regardless of
deadline, but FillRejectedException can be thrown immediately for capacity reasons (“fill queue
full”), not just after a reader’s budget is exhausted. Also, retried is only used to allow one
retry; a second rejection while still before deadline will now be treated as a timeout because the
broad coalesced catch has no deadline guard.

dotnet/EcencyApi/Handlers/SsrRpc.cs[218-285]
dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

### Issue description
`Resolve()` added `catch (FillRejectedException) when (coalesced)` which always maps fill rejection to `Outcome.Timeout` and increments `counter.Timeout`. This is broader than the PR intent (“past the lookup deadline, answer timeout and start no replacement fill”) and can:
- return 504 Timeout even when the lookup deadline has **not** passed (e.g., on a second `FillRejectedException` after the single retry)
- mask non-timeout rejection causes such as `"fill queue full"`

### Issue Context
`FillRejectedException` is thrown for at least two distinct reasons: queue capacity (`"fill queue full"`) and expiry (`"fill expired in queue"`). Only the post-deadline case should be forced into a timeout response per the PR description; otherwise preserve the original behavior (surface as `Unavailable` with the underlying message) or retry while budget remains.

### Fix Focus Areas
- dotnet/EcencyApi/Handlers/SsrRpc.cs[266-295]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]

### Suggested change
Narrow the new catch so it only returns `Outcome.Timeout` when the deadline has passed (e.g., `when (coalesced && Environment.TickCount64 >= deadline)`), and let other `FillRejectedException` cases fall through to the existing general exception handler (or handle them explicitly with `Outcome.Unavailable` and `e.Message`).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

2. Queue-full misreported timeout 🐞 Bug ≡ Correctness

Description

Resolve() now maps any coalesced FillRejectedException to Outcome.Timeout (HTTP 504) even when
the fill was rejected due to internal overload (e.g., "fill queue full"), misclassifying the failure
and incrementing the Timeout counter instead of Error/overload. This can mislead clients/monitoring
by reporting "Upstream Timeout" for a local capacity issue and can change behavior compared to the
previous 502 path.

Code

dotnet/EcencyApi/Handlers/SsrRpc.cs[R281-285]

+        catch (FillRejectedException) when (coalesced)
+        {
+            Interlocked.Increment(ref counter.Timeout);
+            return new Resolution(Outcome.Timeout, Array.Empty<byte>(), "budget exceeded");
+        }

Relevance

●● Moderate

Accepted history supports timeout for expired coalesced fills, but lacks precedent distinguishing
queue saturation from budget expiry.

PR-#73

ⓘ Recommendations generated based on similar findings in past PRs

Evidence

The new catch block unconditionally converts coalesced FillRejectedException into a timeout, but
FillRejectedException is thrown not only for budget expiry but also for internal queue saturation.
Since Outcome.Timeout is mapped to HTTP 504 with an "Upstream Timeout" body, this change
misreports internal overload as upstream timeout and skews the Timeout counter.

dotnet/EcencyApi/Handlers/SsrRpc.cs[271-285]
dotnet/EcencyApi/Handlers/SsrRpc.cs[328-343]
dotnet/EcencyApi/Handlers/SsrRpc.cs[411-416]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`Resolve()` now catches `FillRejectedException` for coalesced readers and always returns `Outcome.Timeout` with `"budget exceeded"`. But `FillRejectedException` is also thrown for internal overload (`"fill queue full"`), which should not be reported as an upstream timeout (HTTP 504) and should not increment the Timeout counter.
### Issue Context
- `Fill()` can throw `FillRejectedException("fill queue full")` when the local fill queue limit is exceeded.
- `Rpc()` maps `Outcome.Timeout` to HTTP 504 + `{ "error": "Upstream Timeout" }`, which is inaccurate for local queue saturation.
### Fix Focus Areas
- dotnet/EcencyApi/Handlers/SsrRpc.cs[271-295]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[320-343]
- dotnet/EcencyApi/Handlers/SsrRpc.cs[399-416]
### Suggested fix
1. Make `FillRejectedException` carry a typed reason (e.g., `enum FillRejectReason { ExpiredInQueue, QueueFull }`), or introduce two distinct exception types.
2. In `Resolve()`:
 - Keep the "retry once" path for `ExpiredInQueue` (only while `TickCount64 < deadline`).
 - If the rejection is `QueueFull`, return a non-timeout outcome (e.g., `Outcome.Unavailable` or a new `Outcome.Overloaded`) and increment an appropriate counter (likely `Error` or a new `Overload`).
 - For `ExpiredInQueue` after the deadline, return `Outcome.Timeout`.
3. Ensure the HTTP mapping matches the outcome (avoid returning 504/"Upstream Timeout" for local overload).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

Context sources

✅ Tickets: 🎫 Internal SSR RPC cache route for vision-web server renders

Review mode: ⚖️ Balanced: This is a localized but behavior-changing concurrency/cache-path fix involving deadline handling and fill capacity, so a careful full review is warranted.

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📥 Commits

Reviewing files that changed from the base of the PR and between 39f7938 and d762fd5.

📒 Files selected for processing (2)

• dotnet/EcencyApi.Tests/SsrRpcTests.cs
• dotnet/EcencyApi/Handlers/SsrRpc.cs

📝 Walkthrough

Walkthrough

Resolve now limits coalesced fill retries to the remaining lookup budget. When the budget expires, it increments the timeout counter and returns a timeout resolution.

Changes

Coalesced fill timeout handling

Layer / File(s)	Summary
Resolve deadline check dotnet/EcencyApi/Handlers/SsrRpc.cs	Resolve retries a coalesced fill rejection only when time remains. Otherwise, it records a timeout and returns a timeout resolution.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: 🔵 Low · up to 39f79

The change stops replacement fills after a reader’s deadline expires, avoiding work for readers that have already timed out; the bounded remaining risk is that this behavior lacks a direct regression test, so the PR is mergeable with explicit owner follow-up.

Poem

I’m a rabbit guarding time,
Rejects retry only in the prime.
When the deadline hops away,
Timeout marks the end of play.
The lookup path now stays precise.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: preventing replacement fills after the SSR RPC cache lookup deadline expires.
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Actionable comments posted: 1

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Inline comments:
In `@dotnet/EcencyApi/Handlers/SsrRpc.cs`:
- Around line 271-285: Add a regression test in SsrRpcTests covering a coalesced
reader whose deadline expires before FillRejectedException is handled. Assert
the resolution outcome is Timeout, the timeout counter increments, and no
replacement Hive call is started after the deadline, using the existing test
setup and call-count mechanisms.

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• dotnet/EcencyApi/Handlers/SsrRpc.cs

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[feruzm]

Added 683b100 after watching the cache on staging: every bridge.* lookup failed with Could not find API bridge while condenser_api.* reads were hitting. Cause: the cache used the legacy {"method":"call","params":[api, method, params]} envelope, which hived resolves only for its own APIs; hivemind's bridge is routed by the dotted method name. HiveRpcClient.CallMethod now sends "method":"bridge.get_post" (modern JSON-RPC form, works for condenser_api too) and the SSR cache uses it for every read. The stub emulates hived's refusal of the legacy form, so the new test fails the old way and passes now.

[feruzm]

Correction: 683b100 landed on this branch after the merge, so it is not on main. The same change is #75.