wallet: Validate all descriptors before rescanning in importdescriptors #33938

1. 
   psam21 commented at 1:29 pm on November 24, 2025: none

   Fixes #33655

   The importdescriptors RPC was performing expensive blockchain rescans even when descriptor validation failed, wasting time and resources.

   Changes

   This PR separates validation logic into a new ValidateDescriptorImport() function that validates all descriptors before any wallet modifications or rescanning occurs.

   Behavior

   • Before: ProcessDescriptorImport() validated and imported descriptors one by one, triggering a rescan even if some descriptors were invalid
   • After: ValidateDescriptorImport() checks all descriptors first, fails fast on any validation error, and only proceeds to ProcessDescriptorImport() and rescanning if all descriptors are valid

   Benefits

   • Fails fast on invalid descriptors without triggering rescan
   • Validates all descriptors upfront before processing any
   • Improves user experience with immediate feedback on validation errors
   • Saves significant time by avoiding unnecessary blockchain rescans
   • Follows the approach suggested by @pinheadmz in the issue discussion
2. wallet: Validate all descriptors before rescanning in importdescriptors

   The importdescriptors RPC was performing a rescan even when descriptor
   validation failed. This wasted time and resources on invalid imports.
   
   This change separates validation into a new ValidateDescriptorImport()
   function that checks all descriptors before any wallet modifications or
   rescanning occurs. If any descriptor fails validation, the function
   returns early with an error, preventing unnecessary blockchain rescans.
   
   Benefits:
   - Fails fast on invalid descriptors without triggering rescan
   - Validates all descriptors upfront before processing any
   - Improves user experience by providing immediate feedback
   - Saves time by avoiding unnecessary blockchain rescans
   
   Fixes #33655

   065e2e56c2
3. DrahtBot added the label Wallet on Nov 24, 2025
4. 
   DrahtBot commented at 1:29 pm on November 24, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33938.

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5. 
   maflcko commented at 1:56 pm on November 24, 2025: member

   thx, but LLM generated pull requests, where the author does not understand the changes themselves, are not accepted:

   • There are no tests
   • The code does not even compile
   • There is a already a pull request and you’d have to review/reflect that one first, as already mentioned previously
6. maflcko closed this on Nov 24, 2025

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Contributors
psam21 DrahtBot maflcko

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Wallet