From cc8c708295ff36352b309d843fddb14418b5a6be Mon Sep 17 00:00:00 2001
From: Johannes Schauer Marin Rodrigues <josch@mister-muffin.de>
Date: Sat, 25 Nov 2023 08:00:19 +0100
Subject: [PATCH] HACKING: how to bisect

---
 HACKING | 39 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/HACKING b/HACKING
index 1c77ee9..ff9784b 100644
--- a/HACKING
+++ b/HACKING
@@ -27,6 +27,41 @@ Making a new release
 
  - Build and upload to pypi:
 
-    $ rm dist/*
+    $ rm -rf dist/*
     $ python3 setup.py sdist
-    $ twine upload --sign dist/*
+    $ twine upload dist/*
+
+Using debbisect to find regressions
+-----------------------------------
+
+    $ debbisect --cache=./cache  --depends="git,ca-certificates,python3,
+           ghostscript,imagemagick,mupdf-tools,poppler-utils,python3-pil,
+           python3-pytest,python3-numpy,python3-scipy,python3-pikepdf" \
+      --verbose  2023-09-16 2023-10-24 \
+      'chroot "$1" sh -c "
+           git clone https://gitlab.mister-muffin.de/josch/img2pdf.git
+           && cd img2pdf
+           && pytest 'src/img2pdf_test.py::test_jpg_2000_rgba8[internal]"'
+
+Using debbisect cache
+---------------------
+
+    $ mmdebstrap --variant=apt --aptopt='Acquire::Check-Valid-Until "false"' \
+          --include=git,ca-certificates,python3,ghostscript,imagemagick \
+          --include=mupdf-tools,poppler-utils,python3-pil,python3-pytest \
+          --include=python3-numpy,python3-scipy,python3-pikepdf \
+          --hook-dir=/usr/share/mmdebstrap/hooks/file-mirror-automount \
+          --setup-hook='mkdir -p "$1/home/josch/git/devscripts/cache/pool/"' \
+          --setup-hook='mount -o ro,bind /home/josch/git/devscripts/cache/pool/ "$1/home/josch/git/devscripts/cache/pool/"' \
+          --chrooted-customize-hook=bash
+          unstable /dev/null
+          file:///home/josch/git/devscripts/cache/archive/debian/20231022T090139Z/
+
+Bisecting imagemagick
+---------------------
+
+    $ git clean -fdx && git reset --hard
+    $ ./configure --prefix=$(pwd)/prefix
+    $ make -j$(nproc)
+    $ make install
+    $ LD_LIBRARY_PATH=$(pwd)/prefix/lib prefix/bin/compare ...