From 07d02e345e852b814dbd302d53d7e424c24a027c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Petazzoni?= <jerome.petazzoni@gmail.com>
Date: Tue, 4 Jan 2022 12:50:20 +0100
Subject: [PATCH] =?UTF-8?q?=F0=9F=9B=A0=EF=B8=8F=20=20Add=20script=20to=20?=
 =?UTF-8?q?find=20unmerged=20changes?=
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---
 slides/find-unmerged-changes.sh | 60 +++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100755 slides/find-unmerged-changes.sh

diff --git a/slides/find-unmerged-changes.sh b/slides/find-unmerged-changes.sh
new file mode 100755
index 00000000..5baf8c1c
--- /dev/null
+++ b/slides/find-unmerged-changes.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+
+# The materials for a given training live in their own branch.
+# Sometimes, we write custom content (or simply new content) for a training,
+# and that content doesn't get merged back to main. This script tries to
+# detect that with the following heuristics:
+# - list all remote branches
+# - for each remote branch, list the changes that weren't merged into main
+#   (using "diff main...$BRANCH", three dots)
+# - ignore a bunch of training-specific files that change all the time anyway
+# - for the remaining files, compute the diff between main and the branch
+#   (using "diff main..$BRANCH", two dots)
+# - ignore changes of less than 10 lines
+# - also ignore a few red herrings
+# - display whatever is left
+
+# For "git diff" (in the filter function) to work correctly, we must be
+# at the root of the repo.
+cd $(git rev-parse --show-toplevel)
+
+BRANCHES=$(git branch -r | grep -v origin/HEAD | grep origin/2)
+
+filter() {
+  threshold=10
+  while read filename; do
+    case $filename in
+      # Generic training-specific files
+      slides/*.html) continue;;
+      slides/*.yml) continue;;
+      slides/logistics*.md) continue;;
+      # Specific content that can be ignored
+      #slides/containers/Local_Environment.md) threshold=100;;
+      # Content that was moved/refactored enough to confuse us
+      slides/containers/Local_Environment.md) threshold=100;;
+      slides/exercises.md) continue;;
+      slides/k8s/batch-jobs) threshold=20;;
+      # Renames
+      */{*}*) continue;;
+    esac
+    git diff --find-renames --numstat main..$BRANCH -- "$filename" | {
+      # If the files are identical, the diff will be empty, and "read" will fail.
+      read plus minus filename || return
+      # Ignore binary files (FIXME though?)
+      if [ $plus = - ]; then
+        return
+      fi
+      diff=$((plus-minus))
+      if [ $diff -gt $threshold ]; then
+        echo git diff main..$BRANCH -- $filename
+      fi
+    }
+  done
+}
+
+for BRANCH in $BRANCHES; do
+  if FILES=$(git diff --find-renames --name-only main...$BRANCH | filter | grep .); then
+    echo "🌳 $BRANCH:"
+    echo "$FILES"
+  fi
+done