Add a check for Xcode.app presence

[nesnrve]

The Xcode application ships all the tools from the standalone CLT at /Applications/Xcode.app/Contents/Developer, but installing brew currently forces a duplicate CLT installation separate from the Xcode application. This change should now make the install script respect the Xcode application if present.

[SMillerDev]

Those are not the same. The CLT from Xcode does not completely match the Command Line Tools package.

[nesnrve]

@SMillerDev that'd be news to me... what's your references?

Edit: I compared the binaries included from the Xcode application and the standalone CLT. As I had expected, Xcode ships all binaries and headers present in the standalone CLT, and more.

The two Xcode paths in interest:

• /Applications/Xcode.app/Contents/Developer
• /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain

vimdiff for binaries:

vimdiff <( (ls /Applications/Xcode.app/Contents/Developer/usr/bin; ls /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin) | sort ) <( ls /Library/Developer/CommandLineTools/usr/bin | sort )

vimdiff for headers:

vimdiff <( (ls /Applications/Xcode.app/Contents/Developer/usr/lib; ls /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib; ls /Applications/Xcode.app/Contents/Developer/Makefiles/pb_makefiles) | sort ) <( ls /Library/Developer/CommandLineTools/usr/lib | sort )

Unless there is something else to it (waiting for @SMillerDev's response), I'll rehearse that I don't think it makes sense having a dependency on the standalone CLT installation when the Xcode application is present, this should be reconsidered and reopened @carlocab.

[carlocab]

This has been discussed at length very many times in various issues and pull requests here and at Homebrew/brew. Please read those instead.

[nesnrve]

@carlocab Cc: @SMillerDev

I've now read #509, #586, #757 and #340. All of which are rehearsing the same statement made in here, that the standalone CLT is "not the same thing" as those provided by the Xcode application, without any references to support that claim whatsoever.

As to my observation above, the Xcode application ships everything you get from the standalone CLT installation, so if a dependance can be declared on the latter then I see no reason why not the former... it'd be sensible if it were vice versa given the standalone CLT doesn't ship everything that's available from the Xcode application, but that appears to not be the case. I'd be pleased to be enlightened further.

[p-linnane]

The fact that major formulae like gcc and [email protected] have issues without CLT being installed is reason enough. Check out the formula files if you want, but there are comments explaining issues with incorrect sysroot, headers that can't be found, etc. unless CLT is installed.

Further, multiple maintainers have stated both in this thread, and the ones you linked, that we won't support this. There's no real obligation on our part to 'prove' to you, or anyone else, why that is.

[MikeMcQuaid]

without any references to support that claim whatsoever.

Here's a reference: we're Homebrew maintainers. I've been doing this for 16 years. I'm in direct communication with Apple around things like the CLT. Homebrew is part of the reason the CLT exists. We know than you about this. We're not obliged (nor is it a good use of our time) to explain to you any more details than have already been provided.