feat: expose lastRetry.exitCodes (all previous attempt exit codes)

[lirons-legit]

• Ran make pre-commit -B
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• Opened as draft; will mark "Ready for review" once builds are green

Fixes #12849

Motivation

lastRetry.exitCode (added in #14450) exposes only the immediately previous attempt, so an expression can't accumulate a resource across retries conditionally. For workloads that fail from more than one cause, both currently-expressible options are wrong:

• key off retries (the index) → escalates on every retry, including non-OOM ones
• lastRetry.exitCode == 137 ? base+step : base → resets to base on any interleaved non-OOM failure, so the next attempt re-OOMs

Real case: sharded scan pods that fail from both OOM (exit 137) and node ephemeral-storage eviction (non-137), interleaved within one retry chain. There is no way today to grow memory once per prior OOM and hold it across evictions.

This is Option 2 from my comment on #12849 (expose retry history, no new stored state) rather than Option 1 (store the previous attempt's applied resource request on NodeStatus). Opened as draft so maintainers can pick the shape — happy to switch to Option 1.

Modifications

Adds lastRetry.exitCodes — a comma-separated string of every previous attempt's exit code (oldest first) — to the lastRetry variables usable in expressions / podSpecPatch:

• util/variables/keys/retries.go: define lastRetry.exitCodes
• workflow/controller/operator.go: inject it (join previous child nodes' exit codes) alongside the other lastRetry.* vars
• util/template/expression_template.go: allow-list it as a late-binding expression variable
• workflow/validate/validate.go: validation placeholder
• docs/variables.md + docs/variable-flow/variables.md (regenerated)

It lets podSpecPatch grow memory once per prior OOM and hold it across evictions, e.g.:

memory: "{{= 2 + len(filter(split(lastRetry.exitCodes, ','), {# == '137'})) }}Gi"

Verification

• Added workflow/controller/operator_test.go: TestLastRetryExitCodesInPodSpecPatch — asserts the memory curve 100→200→200→300→300Mi over a [137,1,137,1] failure sequence (grows on OOM, holds across the non-OOM retries), which is exactly the behavior lastRetry.exitCode alone cannot express.
• Full CI E2E matrix is green on the current head.

Documentation

docs/variables.md and docs/variable-flow/variables.md are regenerated to list lastRetry.exitCodes alongside the existing lastRetry.* variables, so users discover it in the same place as lastRetry.exitCode. No new UI. (A feature description file via make feature-new can be added if maintainers want one for this — happy to add.)

AI

This PR was prepared with the assistance of a generative-AI coding tool (Claude Code) — including the implementation, the test, the docs regeneration, and this description — and reviewed by me before submitting. Per the Argo Generative AI policy.

Summary by CodeRabbit

• New Features

  • Added lastRetry.exitCodes, providing comma-separated exit codes from all previous retry attempts in chronological order.
  • Retry expressions can now respond to cumulative failure history, including repeatedly adjusting resources after specific failures.
  • The value is empty on the first attempt and supports conditional behavior across subsequent retries.

• Documentation

  • Documented the variable’s availability, behavior, and usage examples.

[github-actions]

✅ PR readiness: all clear

All contributor-fixable checks are passing. A maintainer will take it from here — thanks!

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 40.03%. Comparing base (79ef17f) to head (bb57662).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16841      +/-   ##
==========================================
+ Coverage   39.95%   40.03%   +0.08%     
==========================================
  Files         569      569              
  Lines       44724    44738      +14     
==========================================
+ Hits        17869    17911      +42     
+ Misses      25074    25049      -25     
+ Partials     1781     1778       -3     

Flag	Coverage Δ
unit-tests	40.01% <100.00%> (+0.07%)	⬆️
unit-tests-windows	28.85% <100.00%> (+0.05%)	⬆️

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• workflow/controller/operator.go

🚧 Files skipped from review as they are similar to previous changes (1)

• workflow/controller/operator.go

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📝 Walkthrough

Walkthrough

Adds lastRetry.exitCodes, a comma-separated history of prior retry exit codes. The controller populates it during retries. Validation and expression handling recognize it. Documentation and tests cover cumulative OOM-based resource changes.

Changes

Retry exit code history

Layer / File(s)	Summary
Variable contract and resolution util/variables/keys/retries.go, workflow/validate/validate.go, util/template/expression_template.go, workflow/validate/validate_test.go, docs/variables.md, docs/variable-flow/variables.md, .features/pending/last-retry-exit-codes.md	Defines and registers lastRetry.exitCodes as a retry variable. Expression handling treats it as late-bound. Validation, feature documentation, and variable catalogs describe its cumulative retry history.
Runtime history injection workflow/controller/operator.go, workflow/controller/operator_test.go	Collects prior child exit codes in oldest-first order and injects them into retry templates. Tests verify memory increases once per prior OOM exit and remains unchanged across non-OOM retries.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to bb576

The PR adds access to prior retry exit codes so resource adjustments can persist across mixed failure causes. No actionable merge-blocking risk remains, so it is merge-ready after normal checks and review.

Sequence Diagram(s)

sequenceDiagram
  participant RetryController
  participant PriorChildNodes
  participant TemplateExpression
  participant PodSpecPatch
  RetryController->>PriorChildNodes: Collect prior exit codes
  PriorChildNodes-->>RetryController: Return oldest-first history
  RetryController->>TemplateExpression: Inject lastRetry.exitCodes
  TemplateExpression->>PodSpecPatch: Evaluate resource expression
  PodSpecPatch-->>RetryController: Apply memory limit

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🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The PR addresses the linked issue's use case by exposing prior exit-code history, but it does not implement the issue's stated primary requirement to add the previous resource request to lastRetry [#1…	Obtain explicit maintainer approval to use the exit-code-history approach as the solution for #12849, or implement and expose the previous resource request as requested by the issue.
Docstring Coverage	⚠️ Warning	Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 6 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the primary change: exposing all previous retry exit codes through lastRetry.exitCodes.
Description check	✅ Passed	The description includes the motivation, modifications, verification, documentation, linked issue, and AI declaration. Some process checklist items remain unchecked, but the required change details ar…
Out of Scope Changes check	✅ Passed	The implementation, validation changes, tests, feature document, and regenerated documentation all support the retry exit-code history feature. No unrelated code changes are evident.

Full details: Description check

Explanation

The description includes the motivation, modifications, verification, documentation, linked issue, and AI declaration. Some process checklist items remain unchecked, but the required change details are mostly complete.

Full details: Linked Issues check

Explanation

The PR addresses the linked issue's use case by exposing prior exit-code history, but it does not implement the issue's stated primary requirement to add the previous resource request to lastRetry [#12849].

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Actionable comments posted: 1

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Inline comments:
In `@workflow/controller/operator.go`:
- Line 2546: Populate varkeys.RetriesExitCodes.Template() in
buildRetryStrategyLocalScope before processNodeRetries evaluates
retryStrategy.Expression, using the completed oldest-first lastRetryExitCodes
history. Ensure the retry expression receives lastRetry.exitCodes while
preserving the existing localParams assignment behavior.

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📒 Files selected for processing (9)

• .features/pending/last-retry-exit-codes.md
• docs/variable-flow/variables.md
• docs/variables.md
• util/template/expression_template.go
• util/variables/keys/retries.go
• workflow/controller/operator.go
• workflow/controller/operator_test.go
• workflow/validate/validate.go
• workflow/validate/validate_test.go

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[lirons-legit]

Flagging for reviewers re: the linked-issue check — this PR intentionally implements the exit-code-history approach (Option 2 in my comment on #12849) rather than the literal "add the previous resource request to lastRetry" (Option 1).

Rationale: Option 1 requires persisting the applied resource requests on NodeStatus — they live on the Pod, which is GC'd by retry time — i.e. a new stored field. Option 2 reuses each child node's existing Outputs.ExitCode, adds no stored state, and stays in the same lane as #14450. It still solves the issue's motivating use case (accumulate memory per prior OOM) via base + count(prior 137s) * step.

Kept as draft pending a maintainer's call on which shape you'd accept — happy to implement Option 1 (the NodeStatus field) instead if that's preferred.