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@greptileai

Greptile Overview

Greptile Summary

This PR replaces wasteful OOPIF reload logic with an elegant clone-and-replace approach for shadow root piercing. Previously, when the shadow root piercer was injected after custom elements had already created their shadow roots, the code would reload entire iframes to trigger re-creation. The new approach walks the DOM, identifies custom elements missing tracked shadow roots, and clones/replaces them to trigger the connectedCallback() lifecycle method, which re-creates the shadow root under the patched attachShadow() hook.

Key Changes

• Removed complex iframe reload logic (~66 lines) including waitingForDebugger parameter handling and 3-second load timeouts
• Added rerenderMissingShadows.runtime.ts with safe, focused logic to clone and replace custom elements
• Simplified onAttachedToTarget() flow by removing timing-sensitive reload coordination
• Changed ensurePiercer() to return boolean for better error handling
• Added build process for new rerender script in genDomScripts.ts

Analysis

The implementation is well-designed with proper error handling at multiple levels (try-catch in rerender loop, catch blocks on CDP calls). The clone-and-replace approach is more predictable than page reloads and avoids race conditions. The only edge case is custom elements that create shadow roots in constructors before connection, which is already discouraged by web component best practices.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk - it replaces fragile reload logic with a cleaner approach
• Score of 5 reflects well-architected solution with comprehensive error handling, removal of timing-sensitive reload logic, proper integration with existing piercer system, and extensive try-catch blocks preventing failures. The approach is more deterministic than the previous reload-based solution.
• No files require special attention

Important Files Changed

File Analysis

Sequence Diagram

sequenceDiagram
    participant Browser as Chrome/Browser
    participant CDP as CDP Session
    participant Context as V3Context
    participant Piercer as installV3PiercerIntoSession
    participant Document as OOPIF Document
    participant CustomEl as Custom Elements

    Browser->>CDP: Target.attachedToTarget (OOPIF)
    CDP->>Context: onAttachedToTarget()
    Context->>Context: executionContexts.attachSession()
    Context->>Piercer: ensurePiercer(session)
    
    Note over Piercer: Install shadow root piercer
    Piercer->>Document: Page.addScriptToEvaluateOnNewDocument(v3ScriptContent)
    Piercer->>Document: Runtime.evaluate(v3ScriptContent)
    Note over Document: attachShadow() now patched
    
    Note over Piercer: Run rerender script
    Piercer->>Document: Runtime.evaluate(reRenderScriptContent)
    Document->>Document: createTreeWalker() - find custom elements
    Document->>Document: filter elements with missing shadow roots
    
    loop For each missing shadow root
        Document->>CustomEl: cloneNode(true)
        Document->>CustomEl: replaceWith(clone)
        CustomEl->>CustomEl: connectedCallback() triggered
        CustomEl->>Document: attachShadow() [PATCHED]
        Note over Document: Shadow root now tracked!
    end
    
    Piercer-->>Context: return true (success)
    Context->>Context: Continue OOPIF initialization