./configure + homebrew: recommend the script .homebrew-build-env

[jhpalmieri]

When homebrew is detected, the "hints" at the end of running ./configure should suggest running the script .homebrew-build-env.

[Marking it as critical because it has the potential of reducing the number of support questions for release 9.1]

CC: @mkoeppe @dimpase @dcoudert

Component: build: configure

Author: Matthias Koeppe

Branch/Commit: ec64fb6

Reviewer: John Palmieri

Issue created by migration from https://trac.sagemath.org/ticket/29504

[jhpalmieri]

comment:1

Questions:

• should .homebrew-build-env have a #!... line at the top?
• with zsh, the new default shell on OS X, . .homebrew-build-env fails, but source .homebrew-build-env works. Do we always suggest source .homebrew..., or is there a reason to suggest . .homebrew..., for example when using bash? With zsh:

% . .homebrew-build-env     
.: no such file or directory: .homebrew-build-env

I guess in zsh, the correct invocation with . would be . ./.homebrew-...: you have to specify the path.

[mkoeppe]

comment:2

Replying to @jhpalmieri:

Questions:

• should .homebrew-build-env have a #!... line at the top?
• with zsh, the new default shell on OS X, . .homebrew-build-env fails, but source .homebrew-build-env works. Do we always suggest source .homebrew..., or is there a reason to suggest . .homebrew..., for example when using bash? With zsh:

% . .homebrew-build-env     
.: no such file or directory: .homebrew-build-env

I guess in zsh, the correct invocation with . would be . ./.homebrew-...: you have to specify the path.

Good idea. We should recommend source ./.homebrew-build-env then.

No #! because it must be sourced, not executed

[mkoeppe]

comment:3

References:

_ environment variables - What is the difference between '.' and 'source' in shells? - Unix & Linux Stack Exchange
https://unix.stackexchange.com/questions/58514/what-is-the-difference-between-and-source-in-shells

bash - running script with ". " and with "source " - Unix & Linux Stack Exchange
https://unix.stackexchange.com/questions/17815/running-script-with-and-with-source

[mkoeppe]

Branch: u/mkoeppe/__configure___homebrew__recommend_the_script__homebrew_build_env

[mkoeppe]

New commits:

1bb30bf

build/bin/sage-print-system-package-command [homebrew]: Advertise .homebrew-build-env

[mkoeppe]

Author: Matthias Koeppe

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1,2 +1,3 @@
 When homebrew is detected, the "hints" at the end of running `./configure` should suggest running the script `.homebrew-build-env`.
 
+[Marking it as critical because it has the potential of reducing the number of support questions for release 9.1]

[mkoeppe]

Commit: 1bb30bf

[jhpalmieri]

comment:6

Thank you for working on this, but this only prints the message if there are uninstalled homebrew packages. Otherwise, this code gets executed before the message has a chance to be printed:

if [ -z "$system_packages" ]; then
    # No command needed to install nothing
    exit 0
fi

[mwageringel]

Replying to @jhpalmieri:

When homebrew is detected, the "hints" at the end of running ./configure should suggest running the script .homebrew-build-env.

If one sources this file, one would always need to make sure that it is sourced whenever one runs make or sage -b, right? If so, the hint should mention this. Still, I would probably forget about it sooner or later and end up with a broken build.

[jhpalmieri]

comment:8

Replying to @mwageringel:

Replying to @jhpalmieri:

When homebrew is detected, the "hints" at the end of running ./configure should suggest running the script .homebrew-build-env.

If one sources this file, one would always need to make sure that it is sourced whenever one runs make or sage -b, right? If so, the hint should mention this. Still, I would probably forget about it sooner or later and end up with a broken build.

Are you suggesting deleting the file altogether, or automatically running it every time?