fix(#799): preserve child pre_script during base forge composition

[fullsend-ai-coder]

Summary

• Fix base-composition bug where a child harness's explicit pre_script was silently overwritten by the base's forge.<platform>.pre_script during ResolveForge
• After mergeForgeBlocks, clear forge-level pre_script/post_script entries inherited from the base when the child explicitly declared the corresponding top-level field
• Preserve child-authored forge-level scripts (only base-inherited values are cleared)
• Add triage-specific runAgent tests verifying pre-script abort on exit 1 and proceed on exit 0

Root cause

mergeBaseIntoChild correctly preserves the child's top-level pre_script during scalar merge. However, it also merges the base's forge section via mergeForgeBlocks. When the child has no forge section, it inherits the base's forge configs entirely — including forge.github.pre_script. Later, ResolveForge unconditionally overwrites the top-level pre_script with the non-empty forge-level value, silently dropping the child's explicit declaration.

Test plan

• TestMergeBaseIntoChild_ChildPreScriptSurvivesBaseForge — child top-level pre_script survives when base has forge.github.pre_script
• TestMergeBaseIntoChild_ChildForgePreScriptPreserved — child-authored forge-level pre_script is preserved (not cleared)
• TestLoadWithBase_ChildPreScriptSurvivesBaseForgeResolution — end-to-end: child pre_script survives full LoadWithBase + ResolveForge pipeline
• TestLoadWithBase_BaseForgePreScriptInheritedWhenChildOmits — existing behavior unchanged: base forge pre_script inherited when child omits
• TestRunAgent_TriagePreScriptExitsNonZero — triage agent aborts on pre-script exit 1
• TestRunAgent_TriagePreScriptExitsZero_ProceedsToSandbox — triage agent proceeds past pre-script on exit 0
• All existing harness and CLI tests pass

🤖 Generated with Claude Code

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Closes #799

Post-script verification

• Branch is not main/master (agent/799-triage-pre-script)
• Secret scan passed (gitleaks — ba77dbdbbd17e9bb18c47bf6efa023c98b697158..HEAD)
• PR body secret scan passed (gitleaks — no-git)
• Pre-commit hooks passed (authoritative run on runner)
• Tests ran inside sandbox

[fullsend-ai-review]

🤖 Finished Review · ✅ Success · Started 3:16 AM UTC · Completed 3:31 AM UTC
Commit: ab9850b · View workflow run →

[fullsend-ai-review]

Review

Findings

Low

• [naming-consistency] internal/harness/compose.go — The parameter childForgeScripts in clearInheritedForgeScripts and the caller variable childForgeSnap in mergeBaseIntoChild use different abbreviated forms for the same map[string]forgeScriptSnapshot value. Aligning the names would reduce cognitive overhead.

Previous run

Review

Findings

Low

• [architectural-coherence] internal/harness/compose.go:591 — ADR-0045 states forge blocks use "same merge rules" but the fix introduces forge-specific clearing logic that creates an exception for pre_script/post_script during base composition. The inline code comments are thorough, but the ADR itself does not document this exception. Consider adding a brief addendum to ADR-0045 noting that forge-level scripts inherited from a base are cleared when the child declares top-level equivalents.

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Labels: PR fixes a bug in harness base composition (forge script inheritance), part of the dispatch/composition system

[guyoron1]

/fs-fix

[fullsend-ai-coder]

🤖 Finished Fix · ✅ Success · Started 6:48 AM UTC · Completed 6:53 AM UTC
Commit: ab9850b · View workflow run →

[fullsend-ai-coder]

🔧 Fix agent — iteration 1 (human-triggered)

Addressed 1 review finding: added a brief addendum to ADR-0045 documenting the forge-script clearing exception introduced by the #799 fix. The annotation notes that inherited forge-level pre_script/post_script values are cleared when the child declares top-level equivalents, preventing ResolveForge from silently overriding child-authored scripts.

Fixed (1):

1. ADR-0045 does not document forge-script clearing exception (docs/ADRs/0045-forge-portable-harness-schema.md): Added a brief annotation to the base-child merge rules in ADR-0045 documenting that forge-level pre_script/post_script inherited from a base are cleared when the child explicitly declares the corresponding top-level field. This is permitted under ADR rules as a minor annotation (cross-reference to Triage runner does not execute pre_script from harness configuration #799).

Tests: passed

Next steps:

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  _{Updated by fullsend fix agent}

[fullsend-ai-review]

🤖 Finished Review · ✅ Success · Started 6:58 AM UTC · Completed 7:11 AM UTC
Commit: 7239ee3 · View workflow run →

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