From 1e0d06f9be2d03cb2f7c76fa0bbbacdfe6869ac2 Mon Sep 17 00:00:00 2001
From: connoraird <c.aird@ucl.ac.uk>
Date: Thu, 13 Nov 2025 16:58:37 +0000
Subject: [PATCH 1/3] Write PR comment if regression test workflow fails

---
 .github/workflows/regression-test.yaml | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/regression-test.yaml b/.github/workflows/regression-test.yaml
index f555dcf10..b00d99e7b 100644
--- a/.github/workflows/regression-test.yaml
+++ b/.github/workflows/regression-test.yaml
@@ -18,6 +18,9 @@ on:
       - reopened
       - synchronize
 
+env:
+  REGRESSION_TEST_OUTPUT_FILE: output.txt
+
 jobs:
   regression-tests:
     if: github.event.pull_request.draft == false
@@ -54,8 +57,27 @@ jobs:
       - name: Run regression test
         run: >-
           uv run nox -s regression_tests-${{ matrix.python-version }} --
-          "$BASE_REF" "$HEAD_REF"
+          "$BASE_REF" "$HEAD_REF" | tee $REGRESSION_TEST_OUTPUT_FILE
         env:
           BASE_REF: ${{ github.event.pull_request.base.ref }}
           HEAD_REF: ${{ github.event.pull_request.head.ref }}
           FORCE_COLOR: 1
+
+      - name: Extract regression information for PR comment
+        id: extract_comment
+        if: failure()
+        run: >-
+          f=$REGRESSION_TEST_OUTPUT_FILE; start=$(grep -n -m1 'Performance has
+          regressed:' "$f" | cut -d: -f1)
+            || { echo "No match"; exit 1; };
+          s_dash=$(awk -v n=$start 'NR<=n && /^-+$/ {l=NR} END{print l}' "$f");
+          e_dash=$(awk -v n=$start 'NR>=n && /^-+$/ {print NR; exit}' "$f");
+          PR_COMMENT_MSG=$(sed -n "${s_dash},${e_dash}p" "$f"); echo
+          "PR_COMMENT_MSG=$PR_COMMENT_MSG" >> $GITHUB_OUTPUT;
+
+      - name: Write PR comment
+        if: failure()
+        uses: mshick/add-pr-comment@v2
+        with:
+          message: >-
+            ${{ steps.extract_comment.outputs.PR_COMMENT_MSG }}

From 0529911d18220b5e92a0f26fff47eec3b2c583b0 Mon Sep 17 00:00:00 2001
From: connoraird <c.aird@ucl.ac.uk>
Date: Thu, 13 Nov 2025 17:16:21 +0000
Subject: [PATCH 2/3] Don't fail job if regression test fails

---
 .github/workflows/regression-test.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/regression-test.yaml b/.github/workflows/regression-test.yaml
index b00d99e7b..da2f54c65 100644
--- a/.github/workflows/regression-test.yaml
+++ b/.github/workflows/regression-test.yaml
@@ -55,6 +55,7 @@ jobs:
         run: uv sync --only-dev
 
       - name: Run regression test
+        continue-on-error: true
         run: >-
           uv run nox -s regression_tests-${{ matrix.python-version }} --
           "$BASE_REF" "$HEAD_REF" | tee $REGRESSION_TEST_OUTPUT_FILE

From 75a8e34a9989727a39cfa2d1428d6095132d609a Mon Sep 17 00:00:00 2001
From: connoraird <c.aird@ucl.ac.uk>
Date: Tue, 18 Nov 2025 16:25:29 +0000
Subject: [PATCH 3/3] double escape in workflow

---
 .github/workflows/regression-test.yaml | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/regression-test.yaml b/.github/workflows/regression-test.yaml
index da2f54c65..3a8db2082 100644
--- a/.github/workflows/regression-test.yaml
+++ b/.github/workflows/regression-test.yaml
@@ -58,7 +58,7 @@ jobs:
         continue-on-error: true
         run: >-
           uv run nox -s regression_tests-${{ matrix.python-version }} --
-          "$BASE_REF" "$HEAD_REF" | tee $REGRESSION_TEST_OUTPUT_FILE
+          "${BASE_REF}" "${HEAD_REF}" | tee ${REGRESSION_TEST_OUTPUT_FILE}
         env:
           BASE_REF: ${{ github.event.pull_request.base.ref }}
           HEAD_REF: ${{ github.event.pull_request.head.ref }}
@@ -68,13 +68,13 @@ jobs:
         id: extract_comment
         if: failure()
         run: >-
-          f=$REGRESSION_TEST_OUTPUT_FILE; start=$(grep -n -m1 'Performance has
-          regressed:' "$f" | cut -d: -f1)
+          f=${REGRESSION_TEST_OUTPUT_FILE}; start=$(grep -n -m1 'Performance has
+          regressed:' "${f}" | cut -d: -f1)
             || { echo "No match"; exit 1; };
-          s_dash=$(awk -v n=$start 'NR<=n && /^-+$/ {l=NR} END{print l}' "$f");
-          e_dash=$(awk -v n=$start 'NR>=n && /^-+$/ {print NR; exit}' "$f");
-          PR_COMMENT_MSG=$(sed -n "${s_dash},${e_dash}p" "$f"); echo
-          "PR_COMMENT_MSG=$PR_COMMENT_MSG" >> $GITHUB_OUTPUT;
+          s_dash=$(awk -v n=${start} 'NR<=n && /^-+$/ {l=NR} END{print l}'
+          "${f}"); e_dash=$(awk -v n=${start} 'NR>=n && /^-+$/ {print NR; exit}'
+          "${f}"); PR_COMMENT_MSG=$(sed -n "${s_dash},${e_dash}p" "${f}"); echo
+          "PR_COMMENT_MSG=${PR_COMMENT_MSG}" >> ${GITHUB_OUTPUT};
 
       - name: Write PR comment
         if: failure()