compare_force_pushes.sh

#!/usr/bin/env bash

# Got these from the event that reads like:
#  "dbalatero force-pushed the my-feature-branch branch from 7c66458 to c559af0"
old_head=7c66458
new_head=c559af0

echo "CASE 1: A force-pushed branch that has no branch changes, just the latest master"
echo "  e.g. they just did git rebase master && git push --force-with-lease"
echo
echo "With PR: https://github.com/dbalatero/test-repo/pull/1"
echo "It had been force pushed from $old_head to $new_head, with no distinguishable changes."
echo

old_diff=$(curl --silent -H 'Accept: application/vnd.github.v3.diff' \
  https://github.com/dbalatero/test-repo/compare/master...$old_head.diff)

echo "Patch from $old_head:"
echo "===="
echo "$old_diff"
echo
echo "MD5 sum: $(echo "$old_diff" | md5sum)"
echo

new_diff=$(curl --silent -H 'Accept: application/vnd.github.v3.diff' \
  https://github.com/dbalatero/test-repo/compare/master...$new_head.diff)

echo "Patch from $new_head:"
echo "===="
echo "$new_diff"
echo
echo "MD5 sum: $(echo "$new_diff" | md5sum)"
echo

#############################################

old_head=eabdef5
new_head=e20185f

echo "================================"
echo
echo "CASE 2: A branch that pushed changes, then did more work and rebased master, then force pushed"
echo
echo "With PR: https://github.com/dbalatero/test-repo/pull/3"
echo

old_diff=$(curl --silent -H 'Accept: application/vnd.github.v3.diff' \
  https://github.com/dbalatero/test-repo/compare/master...$old_head.diff)

echo "Patch from $old_head:"
echo "===="
echo "$old_diff"
echo
echo "MD5 sum: $(echo "$old_diff" | md5sum)"
echo

new_diff=$(curl --silent -H 'Accept: application/vnd.github.v3.diff' \
  https://github.com/dbalatero/test-repo/compare/master...$new_head.diff)

echo "Patch from $new_head:"
echo "===="
echo "$new_diff"
echo
echo "MD5 sum: $(echo "$new_diff" | md5sum)"
echo

output.txt

CASE 1: A force-pushed branch that has no branch changes, just the latest master
  e.g. they just did git rebase master && git push --force-with-lease

With PR: https://github.com/dbalatero/test-repo/pull/1
It had been force pushed from 7c66458 to c559af0, with no distinguishable changes.

Patch from 7c66458:
====
diff --git a/new-file b/new-file
new file mode 100644
index 0000000..e69de29

MD5 sum: 5dd247d9772a9986e1aaa72f864827b0  -

Patch from c559af0:
====
diff --git a/new-file b/new-file
new file mode 100644
index 0000000..e69de29

MD5 sum: 5dd247d9772a9986e1aaa72f864827b0  -

================================

CASE 2: A branch that pushed changes, then did more work and rebased master, then force pushed

With PR: https://github.com/dbalatero/test-repo/pull/3

Patch from eabdef5:
====
diff --git a/file1 b/file1
new file mode 100644
index 0000000..e69de29

MD5 sum: 46040c4064f8683521177d7aee92aebc  -

Patch from e20185f:
====
diff --git a/file1 b/file1
new file mode 100644
index 0000000..e69de29
diff --git a/file2 b/file2
new file mode 100644
index 0000000..e69de29

MD5 sum: afba85eabc2d5d5d50b3b64da6151b48  -