https://github.com/davidcole1340/ext-php-rs/blob/060c8bfb2dacffe35cffb558d4f3738d86a5d34c/crates/cli/src/lib.rs#L224
The problem
If you are outside docker and/or don't have permissions to write into PHP's config directory.
cargo php install will fail if normal user don't have permissions to copy file or write to .ini file.
sudo cargo php install is likely to fail with cargo not found error since cargo is typically installed in user's ~/.cargo/bin directory.
sudo ~/.cargo/bin/cargo php install is likely to rebuild and change the owner to root of many intermediate files to make normal cargo b to fail.
Solution: before copying file or editing INI file, check if it requires admin privilege and use sudo2 or elevate crate to escalate privilege.