Trouble installing `7zip`

[langsharpe]

I had trouble installing 7zip using this buildpack. I'm not sure if the issue is the buildpack or the package.

The repo has an Aptfile with just 7zip in it. The buildpack is the edge version (but I also had this problem with the stable version). The app uses the heroku-24 stack.

I expected that if I ran a dyno, I'd be able to execute 7z. Instead I received this error message.

~ $ 7z
/app/.apt/usr/bin/7z: 2: exec: /usr/lib/7zip/7z: not found

~ $ cat /app/.apt/usr/bin/7z
#! /bin/sh
exec /usr/lib/7zip/7z "$@"

I eventually found the binary:

~ $ find / -name 7z
find: ‘/etc/ssl/private’: Permission denied
find: ‘/lost+found’: Permission denied
find: ‘/proc/tty/driver’: Permission denied
/app/.apt/usr/bin/7z
/app/.apt/usr/lib/7zip/7z

~ $ /app/.apt/usr/lib/7zip/7z

7-Zip 23.01 (x64) : Copyright (c) 1999-2023 Igor Pavlov : 2023-06-20

Here is the relevant section from the build log:

-----> Detected Aptfile or Stack changes, flushing cache
-----> Updating APT package index
       Get:1 http://security.ubuntu.com/ubuntu noble-security InRelease [126 kB]
       Get:2 http://security.ubuntu.com/ubuntu noble-security/main amd64 Packages [777 kB]
       Get:3 http://archive.ubuntu.com/ubuntu noble InRelease [256 kB]
       Get:4 http://security.ubuntu.com/ubuntu noble-security/universe amd64 Packages [1,039 kB]
       Get:5 https://apt.postgresql.org/pub/repos/apt noble-pgdg InRelease [129 kB]
       Get:6 http://archive.ubuntu.com/ubuntu noble-updates InRelease [126 kB]
       Get:7 http://archive.ubuntu.com/ubuntu noble-backports InRelease [126 kB]
       Get:8 http://archive.ubuntu.com/ubuntu noble/universe amd64 Packages [19.3 MB]
       Get:9 https://apt.postgresql.org/pub/repos/apt noble-pgdg/main amd64 Packages [500 kB]
       Get:10 http://archive.ubuntu.com/ubuntu noble/main amd64 Packages [1,808 kB]
       Get:11 http://archive.ubuntu.com/ubuntu noble-updates/universe amd64 Packages [1,317 kB]
       Get:12 http://archive.ubuntu.com/ubuntu noble-updates/main amd64 Packages [1,100 kB]
       Get:13 http://archive.ubuntu.com/ubuntu noble-backports/universe amd64 Packages [15.1 kB]
       rm: cannot remove '/var/cache/apt/archives/partial/*.deb': Permission denied
       Fetched 26.6 MB in 2s (11.6 MB/s)
       Reading package lists...
-----> Fetching .debs for 7zip
       Reading package lists...
       Building dependency tree...
       Suggested packages:
         7zip-standalone 7zip-rar
       The following NEW packages will be installed:
         7zip
       0 upgraded, 1 newly installed, 0 to remove and 101 not upgraded.
       Need to get 1,846 kB of archives.
       After this operation, 6,306 kB of additional disk space will be used.
       Get:1 http://archive.ubuntu.com/ubuntu noble/universe amd64 7zip amd64 23.01+dfsg-11 [1,846 kB]
       Fetched 1,846 kB in 1s (2,343 kB/s)
       Download complete and in download only mode
-----> Installing 7zip_23.01+dfsg-11_amd64.deb
-----> Writing profile script
-----> Rewrite package-config files

Let me know if I can provide any more information.

[colincasey]

Hi @langsharpe, thanks for reporting this.

It looks like the buildpack installed the 7zip package correctly. The problem seems to be that the 7z executable found on the PATH (/app/.apt/usr/bin/7z) is not the actual binary but a shell script containing the following:

#! /bin/sh
exec /usr/lib/7zip/7z "$@"

Due to the way this buildpack has to relocate packages, the hardcoded path in the script above will not work since the actual path to the binary is /app/.apt/usr/lib/7zip/7z. This is why you get this error message:

~ $ 7z
/app/.apt/usr/bin/7z: 2: exec: /usr/lib/7zip/7z: not found

Hardcoded paths in packages aren't easy to accommodate for by this buildpack and, in those cases, some extra user configuration is required. One of the following workarounds may work for you:

• Build & run time - adding heroku/inline-buildpack after this buildpack and, using a bin/compile script, replace the /app/.apt/usr/bin/7z bash script with one that calls exec /app/.apt/usr/lib/7zip/7z "$@"
• Run time only - use a .profile script to prepend the /app/.apt/usr/lib/7zip directory to PATH so it comes before /app/.apt/usr/bin