From 6a09ef5170e7ce6d7ed573fbb08aacece950cecf Mon Sep 17 00:00:00 2001
From: Erik Darling <2136037+erikdarlingdata@users.noreply.github.com>
Date: Sun, 3 May 2026 10:24:11 -0400
Subject: [PATCH] CI: pin paths-filter base to previous commit on push events

dorny/paths-filter@v3 defaults to comparing against the default branch
on push events to non-default branches, which made every push to dev
match the lite_analysis filter (dev is ~1200 commits ahead of main).

Set base explicitly to github.event.before for push events; leave it
empty on pull_request so the action keeps its PR-base default.
---
 .github/workflows/build.yml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 1228aac..3c5b35c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -25,6 +25,11 @@ jobs:
         if: github.event_name != 'release'
         uses: dorny/paths-filter@v3
         with:
+          # On push events, compare against the previous commit on this branch
+          # (github.event.before). Without this, the action defaults to comparing
+          # against the default branch on non-default branch pushes, which would
+          # match every accumulated change and defeat the filter.
+          base: ${{ github.event_name == 'push' && github.event.before || '' }}
           filters: |
             lite_analysis:
               - 'Lite/Analysis/**'