Bitbucket pipeline installing the wrong version of cmake - linux

Question

When I apt-get install cmake in my Bitbucket pipeline, it installs version 3.0.2. This then leads to an error "CMake 3.7.2 or higher is required. You are running version 3.0.2". How can I install cmake version 3.7.2 or higher in my .yml?
bitbucket-pipelines.yml
image: gcc:6.5
pipelines:
default:
- step:
script: # Modify the commands below to build your repository.
- apt-get update && apt-get -y install cmake
- cmake -B build .
Error:
+ cmake -B build .
CMake Error at CMakeLists.txt:1 (cmake_minimum_required):
CMake 3.7.2 or higher is required. You are running version 3.0.2

Answer 1

This isn't really a pipelines issue. I'll walk through the troubleshooting process to identify the problem and a possible solution. You could pursue other solutions to install your desired version but hopefully following the approach here will help you in future.
Full disclosure, I work for Atlassian - though not on the Bitbucket Pipelines team :)
The version of cmake that you see being installed is actually related to the third party base image you're using, gcc:6.5. You can test/verify this on your own machine:
$ docker run --rm -it gcc:6.5 bash
root#77d4fde67119:/# apt-get update && apt-get -y install cmake
root#77d4fde67119:/# cmake --version
cmake version 3.0.2
CMake suite maintained and supported by Kitware (kitware.com/cmake).
We can see the gcc:6.5 image is based on Debian Jessie:
root#77d4fde67119:/# cat /etc/os-release | grep PRETTY
PRETTY_NAME="Debian GNU/Linux 8 (jessie)"
If you look up the default cmake package for Jessie you'll find that it's v3.0.2: https://packages.debian.org/jessie/devel/cmake
A little more digging will show you that newer Debian versions package newer versions of cmake by default: Stretch or Buster will package 3.7 or 3.13 respectively. So the solution to your issue is using a newer version of the gcc base image based on a more recent Debian version:
Let's try it again with the gcc:7 base image:
$ docker run --rm -it gcc:7 bash
root#26e82f7b5e56:/# cat /etc/os-release | grep PRETTY
PRETTY_NAME="Debian GNU/Linux 10 (buster)"
Well, that's a good sign: gcc:7 is based on Debian Buster. Buster ships 3.13: https://packages.debian.org/buster/devel/cmake
root#26e82f7b5e56:/# apt-get update && apt-get -y install cmake
root#26e82f7b5e56:/# cmake --version
cmake version 3.13.4
CMake suite maintained and supported by Kitware (kitware.com/cmake).
There you have it: a version above 3.7.
If you can't use this version of gcc, of course, you'll need to look at a different solution. But hopefully this helps to illustrate the source of your issue and how you can investigate these kinds of issues in future.