[deathanatos]

> One of them being that you typically must be root to install packages.

  ./configure --prefix=$HOME/opt/$pkgname && make && make install

It's not pretty, I'll admit, and package managers could probably help here, if they're building from source.

> but can also be "reverted" back to exactly the same "pre-package-installation" state if wanted.

For system-wide packages, most package managers do support this. Since they don't support user-only packages, of course reverting an install isn't going to happen.

If you've installed it yourself, `rm -rf $HOME/opt/$pkgname`.

> The other very serious issue is that most package builds are not deterministic.

Deterministic builds are hard.

> be able to create the exact same package on different architectures and cross-check that we've got the same results

Unless you're cross-compiling, different architectures by definition nets you different builds. Even within an architecture, differences in feature sets (take advantage of Intel's shiniest instruction?) and compile time options (use this library?), where to install, etc. cause the number of possible build combinations to multiply quickly. Binary distros like Debian have it a bit easier, as they usually distribute a lowest-common-denominator binary with all features, but some distributions (I'm a Gentoo user) let you tune the system more.

Even if you had all the things you name, you still have to trust whomever is packaging your software. Or build it yourself after reading the entire source. (And then there's the chicken-and-egg problem with the compiler.)

[Dylan16807]

Manual builds work fine for some programs, but when you have to have a dozen dependencies that now also have to be built manually, and those have their own dependencies...

[e12e]

Just a quick note for those following along at home, I recommend having a look at xstow for managing custom package(trees). Basically it's:

    mkdir ~/opt/xstow
    cd /tmp
    # get package (verify signature)
    cd package
    ./cofigure --prefix=$HOME/opt
    make
    make install prefix=$HOME/opt/xstow/package-version
    cd ~/opt/xstow
    xstow package-version # xstow -D to "uninstall"

I find that helps a lot when you need to install new versions, and don't want to worry about cruft left over -- and also simplifies handling of PATH, MANPATH, LD_LIBRARY_PATH and LD_RUN_PATH.

Some packages are a little harder, but can sometimes be tricked to behave by moving ~/opt/xstow out of the way, doing a make install and then moving ~/opt to ~/opt/xstow/package-version-etc and xstow'ing.

[e12e]

That's: http://xstow.sourceforge.net/