Add x.py setup

[jyn514]

Closes #76503.

• Suggest x.py setup if config.toml doesn't exist yet
• Prompt for a profile if not given on the command line
• Print the configuration that will be used
• Print helpful starting commands after setup
• Link to the dev-guide after finishing

[jyn514]

Example output:

$ ./x.py check
Updating only changed submodules
Submodules updated in 0.01 seconds
    Finished dev [unoptimized + debuginfo] target(s) in 0.09s
warning: you have not made a `config.toml`
help: consider running `x.py setup` or copying `config.toml.example`
...
$ ./x.py setup
Updating only changed submodules
Submodules updated in 0.01 seconds
    Finished dev [unoptimized + debuginfo] target(s) in 0.09s
Welcome to the Rust project! What do you want to do with x.py?
a) Contribute to the standard library
b) Contribute to the compiler
c) Contribute to the compiler, and also modify LLVM or codegen
d) Install Rust from source
Please choose one (a/b/c/d): a
`x.py` will now use the configuration at /home/joshua/rustc2/src/bootstrap/defaults/config.toml.library
To get started, try one of the following commands:
- `x.py check`
- `x.py build`
- `x.py test library/std`
- `x.py doc`
For more suggestions, see https://rustc-dev-guide.rust-lang.org/building/suggested.html
Build completed successfully in 0:00:05
$ ./x.py setup
Welcome to the Rust project! What do you want to do with x.py?
a) Contribute to the standard library
b) Contribute to the compiler
c) Contribute to the compiler, and also modify LLVM or codegen
d) Install Rust from source
Please choose one (a/b/c/d): a
error: you asked `x.py` to setup a new config file, but one already exists at `config.toml`
help: try adding `profile = "library"` at the top of config.toml
note: this will use the configuration in /home/joshua/rustc2/src/bootstrap/defaults/config.toml.library
failed to run: /home/joshua/rustc2/build/bootstrap/debug/bootstrap setup
Build completed unsuccessfully in 0:00:01

[est31]

In my personal workflow, I cp config.toml.example to config.toml and then adjust the settings I want adjusted. That way their documentation is next to them and I always know what they do. I regularly re-do this step so that it doesn't bitrot too much as new options are being added/old ones removed. But maybe it is smarter to just have that single line instead plus 1 comment.

[jyn514]

I regularly re-do this step so that it doesn't bitrot too much as new options are being added/old ones removed.

This is the main reason for having the defaults in a separate file tracked by git - I don't want people to have to rerun this command as options are changed. I also want to avoid overwhelming people with too many options, I've had a lot of people say config.toml.example is so big it's hard to find anything. The defaults in src/bootstrap/defaults only have a few options, and each of them are commented.

[jyn514]

Before merging this I'd like to also print the help message mentioned at the end of #76503:

Done.

[jyn514]

r? @Mark-Simulacrum

[jyn514]

cc @Lokathor and @thomcc - is there anything else you'd like this to do? Is the output too verbose?

[jyn514]

Ooh, this could also link to https://rustc-dev-guide.rust-lang.org/building/suggested.html once it finishes.

[jyn514]

@Mark-Simulacrum do you have suggestions for setting profile = "user" by default in configure.py? I tried this, but it's not working:

diff --git a/src/bootstrap/configure.py b/src/bootstrap/configure.py
index 47673ce1e87..ac213b55873 100755
--- a/src/bootstrap/configure.py
+++ b/src/bootstrap/configure.py
@@ -34,6 +34,8 @@ def v(*args):
 o("debug", "rust.debug", "enables debugging environment; does not affect optimization of bootstrapped code (use `--disable-optimize` for that)")
 o("docs", "build.docs", "build standard library documentation")
 o("compiler-docs", "build.compiler-docs", "build compiler documentation")
+v("profile", "profile", "the latest version of the x.py changelog viewed")
 o("optimize-tests", "rust.optimize-tests", "build tests with optimizations")
 o("parallel-compiler", "rust.parallel-compiler", "build a multi-threaded rustc")
 o("verbose-tests", "rust.verbose-tests", "enable verbose output when running tests")
@@ -279,6 +281,7 @@ def set(key, value):
     arr = config
     parts = key.split('.')
     for i, part in enumerate(parts):
+        print(i, part)
         if i == len(parts) - 1:
             arr[part] = value
         else:
@@ -362,6 +365,7 @@ set('build.configure-args', sys.argv[1:])
 sections = {}
 cur_section = None
 sections[None] = []
+sections[0] = ["profile"]
 section_order = [None]
 targets = {}
 
@@ -392,6 +396,8 @@ for target in configured_targets:
     targets[target] = sections['target'][:]
     targets[target][0] = targets[target][0].replace("x86_64-unknown-linux-gnu", target)
 
+# Set the default profile to 'user', since contributors won't be using `configure`
+set("profile", "user")
 
 def is_number(value):
     try:

$ ./configure 
configure: processing command line
configure: 
configure: build.configure-args := []
0 build
1 configure-args
configure: profile              := user
0 profile
Traceback (most recent call last):
  File "./src/bootstrap/configure.py", line 449, in <module>
    raise RuntimeError("config key {} not in sections".format(section_key))
RuntimeError: config key profile not in sections

[jyn514]

The other option is to leave that for later so we can land this quickly and then improve the defaults for distro maintainers in a follow-up.

[Mark-Simulacrum]

Yeah, I'm not sure. I would leave it to a future PR.

[jyn514]

Ok, in that case I think this is ready to merge :)

[jyn514]

Because github isn't showing it, the last change I made was

commit 7304b64d28415841c6d1b07501194471109f917e
Author: Joshua Nelson <jyn514@gmail.com>
Date:   Thu Sep 24 10:31:54 2020 -0400

    Note that distro maintainers will see the changelog warning
    
    My previous TODO was incorrect

diff --git a/src/bootstrap/bin/main.rs b/src/bootstrap/bin/main.rs
index 8290420ec06..669dd7a33de 100644
--- a/src/bootstrap/bin/main.rs
+++ b/src/bootstrap/bin/main.rs
@@ -15,7 +15,8 @@ fn main() {
 
     let changelog_suggestion = check_version(&config);
 
-    // TODO: `./configure` should show a warning about the changelog, not `x.py setup`
+    // NOTE: Since `./configure` generates a `config.toml`, distro maintainers will see the
+    // changelog warning, not the `x.py setup` message.
     let suggest_setup = !config.config.exists() && !matches!(config.cmd, Subcommand::Setup { .. });
     if suggest_setup {
         println!("warning: you have not made a `config.toml`");

[Mark-Simulacrum]

@bors r+

[bors]

📌 Commit 9baa601 has been approved by Mark-Simulacrum