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| -rw-r--r-- | doc/devblog/day_60__damage_driven_development.mdwn | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/doc/devblog/day_60__damage_driven_development.mdwn b/doc/devblog/day_60__damage_driven_development.mdwn new file mode 100644 index 000000000..64460e86a --- /dev/null +++ b/doc/devblog/day_60__damage_driven_development.mdwn @@ -0,0 +1,36 @@ +Wrote some evil code you don't want to run today. Git.Destroyer randomly +generates Damage, and applies it to a git repository, in a way that is +reproducible -- applying the same Damage to clones of the same git repo +will always yeild the same result. + +This let me build a test harness for git-repair, which repeatedly clones, +damages, and repairs a repository. And when it fails, I can just ask it to +retry after fixing the bug and it'll re-run every attempt it's logged. + +This is already yeilding improvements to the git-repair code. +The first randomly constructed Damage that it failed to recover +turned out to be a truncated index file that hid some other +corrupted object files from being repaired. + + [Damage Empty (FileSelector 1), + Damage Empty (FileSelector 2), + Damage Empty (FileSelector 3), + Damage Reverse (FileSelector 3), + Damage (ScrambleFileMode 3) (FileSelector 5), + Damage Delete (FileSelector 9), + Damage (PrependGarbage "¥SOH¥STX¥ENQ¥f¥a¥ACK¥b¥DLE¥n") (FileSelector 9), + Damage Empty (FileSelector 12), + Damage (CorruptByte 11 25) (FileSelector 6), + Damage Empty (FileSelector 5), + Damage (ScrambleFileMode 4294967281) (FileSelector 14) + ] + +I need to improve the ranges of files that it damages -- currently QuickCheck +seems to only be selecting one of the first 20 or so files. Also, it's quite +common that it will damage `.git/config` so badly that git thinks it's not +a git repository anymore. I am not sure if that is something `git-repair` +should try to deal with. + +--- + +Today's work was sponsored by the WikiMedia Foundation. |