~/win64-6.4
$ git bisect bad
2631040cfa306940028c830be647cc474604fa17 is the first bad commit
commit 2631040cfa306940028c830be647cc474604fa17
Author: Norbert Thiebaud <nthiebaud@gmail.com>
Date:   Tue Sep 17 00:05:32 2019 -0700

    source sha:c56bf1479cc71d1a2b0639f6383e90c1f7e3655b

    source sha:c56bf1479cc71d1a2b0639f6383e90c1f7e3655b

:040000 040000 e7b367eaebb91ead5e514dd2d8b608299714c14a fb21767b6c4f2130ab7e3ab6228991dee1922c8c M      instdir

~/win64-6.4
$ git bisect log
# bad: [75af2782b7f006d1c31ad11e84d5ab6bd7f74ed0] source sha:20be5cd0bdc57d812bf34a2debfe48caa51de881
# good: [8d1eaf05d47fd1c56ddecbe57a9a7c8289ede7f4] source sha:c98b1f1cd43b3e109bcaf6324ef2d1f449b34099
git bisect start 'origin/master' 'oldest'
# good: [e13037966b62b9d258d5cf6d96586de5e2bafea8] source sha:4a0b2b8024fa6fb8a0ab3e474b7d64fc455028b5
git bisect good e13037966b62b9d258d5cf6d96586de5e2bafea8
# bad: [7cba838374e1acd7b8a6e114d7b12bf6370cd7ab] source sha:d6ea967e040d01ec69649ac689472018e477db34
git bisect bad 7cba838374e1acd7b8a6e114d7b12bf6370cd7ab
# bad: [f57765d2816781c79fc36e1d4955bff1c5c92f8d] source sha:130b0ffd491015df2dc1d6b272952d76980f0465
git bisect bad f57765d2816781c79fc36e1d4955bff1c5c92f8d
# good: [a5806767f5af962cc752a93c633c2a8eb53b7ada] source sha:17f9aa97f8753b895db30e8080481f5f6d696b82
git bisect good a5806767f5af962cc752a93c633c2a8eb53b7ada
# bad: [41393e001db669c50f2ccc3fef02010fc57b3b47] source sha:ea4f3099d6e0cf30d80caa8b2121c7a358f80fdd
git bisect bad 41393e001db669c50f2ccc3fef02010fc57b3b47
# good: [f04a861f07d91a46ce9048e9de0bdd6def5c6a0c] source sha:0d90da9ea0a23c9c4afac62025208559b1496a0e
git bisect good f04a861f07d91a46ce9048e9de0bdd6def5c6a0c
# bad: [84b842cc360f2743a5a8b7b414ae89a4b3b577dc] source sha:77fc63f39c7990ccd3f152ad9311656b58f718a2
git bisect bad 84b842cc360f2743a5a8b7b414ae89a4b3b577dc
# bad: [ec2d30657314bd519cb8442e77df2776d7183ec9] source sha:1e202ec8aa177d427c5173c5290e09aec1e5c720
git bisect bad ec2d30657314bd519cb8442e77df2776d7183ec9
# good: [53e55108c33aa9827ca4c9dec33a5a4f7a0d0e9f] source sha:813cca94cd3a08d98c09fc7c34afddd02dc912ce
git bisect good 53e55108c33aa9827ca4c9dec33a5a4f7a0d0e9f
# bad: [25a6406a056f20cd33f75074917a6af30e0a526a] source sha:5ba30f588d6e41a13d68b1461345fca7a7ca61ac
git bisect bad 25a6406a056f20cd33f75074917a6af30e0a526a
# bad: [6e9d0cf40e05309331c9dbe7726189cb3e23d991] source sha:a944d4c2aacafdac78eabd7fb0f8909a66d935eb
git bisect bad 6e9d0cf40e05309331c9dbe7726189cb3e23d991
# bad: [08503867ad3e26a8a86fe14dadb4cb31f75594b9] source sha:8083ccef3759b2d838df86965c0d1b42f9098848
git bisect bad 08503867ad3e26a8a86fe14dadb4cb31f75594b9
# bad: [2631040cfa306940028c830be647cc474604fa17] source sha:c56bf1479cc71d1a2b0639f6383e90c1f7e3655b
git bisect bad 2631040cfa306940028c830be647cc474604fa17
# first bad commit: [2631040cfa306940028c830be647cc474604fa17] source sha:c56bf1479cc71d1a2b0639f6383e90c1f7e3655b