如题，报一系列如下错误：

error: git-for-windows: signature from "Johannes Schindelin <johannes.schindelin@gmx.de>" is invalid
error: git-for-windows-mingw32: signature from "Johannes Schindelin <johannes.schindelin@gmx.de>" is invalid
error: mingw32: signature from "Christoph Reiter (MSYS2 development key) <reiter.christoph@gmail.com>" is invalid
error: mingw64: signature from "Christoph Reiter (MSYS2 development key) <reiter.christoph@gmail.com>" is invalid
error: ucrt64: signature from "Christoph Reiter (MSYS2 development key) <reiter.christoph@gmail.com>" is invalid
error: clang32: signature from "Christoph Reiter (MSYS2 development key) <reiter.christoph@gmail.com>" is invalid
error: clang64: signature from "Christoph Reiter (MSYS2 development key) <reiter.christoph@gmail.com>" is invalid
error: msys: signature from "Christoph Reiter (MSYS2 development key) <reiter.christoph@gmail.com>" is invalid
error: database 'git-for-windows' is not valid (invalid or corrupted database (PGP signature))
error: database 'git-for-windows-mingw32' is not valid (invalid or corrupted database (PGP signature))
error: database 'mingw32' is not valid (invalid or corrupted database (PGP signature))
error: database 'mingw64' is not valid (invalid or corrupted database (PGP signature))
error: database 'ucrt64' is not valid (invalid or corrupted database (PGP signature))
error: database 'clang32' is not valid (invalid or corrupted database (PGP signature))
error: database 'clang64' is not valid (invalid or corrupted database (PGP signature))
error: database 'msys' is not valid (invalid or corrupted database (PGP signature))

解决方案：删除 \var\lib\pacman\sync，然后按提示重新生成即可。