bootstrap/core/build_steps/
setup.rs

1//! First time setup of a dev environment
2//!
3//! These are build-and-run steps for `./x.py setup`, which allows quickly setting up the directory
4//! for modifying, building, and running the compiler and library. Running arbitrary configuration
5//! allows setting up things that cannot be simply captured inside the config.toml, in addition to
6//! leading people away from manually editing most of the config.toml values.
7
8use std::env::consts::EXE_SUFFIX;
9use std::fmt::Write as _;
10use std::fs::File;
11use std::io::Write;
12use std::path::{MAIN_SEPARATOR_STR, Path, PathBuf};
13use std::str::FromStr;
14use std::{fmt, fs, io};
15
16use sha2::Digest;
17
18use crate::core::builder::{Builder, RunConfig, ShouldRun, Step};
19use crate::utils::change_tracker::CONFIG_CHANGE_HISTORY;
20use crate::utils::exec::command;
21use crate::utils::helpers::{self, hex_encode};
22use crate::{Config, t};
23
24#[cfg(test)]
25mod tests;
26
27#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
28pub enum Profile {
29    Compiler,
30    Library,
31    Tools,
32    Dist,
33    None,
34}
35
36static PROFILE_DIR: &str = "src/bootstrap/defaults";
37
38impl Profile {
39    fn include_path(&self, src_path: &Path) -> PathBuf {
40        PathBuf::from(format!("{}/{PROFILE_DIR}/config.{}.toml", src_path.display(), self))
41    }
42
43    pub fn all() -> impl Iterator<Item = Self> {
44        use Profile::*;
45        // N.B. these are ordered by how they are displayed, not alphabetically
46        [Library, Compiler, Tools, Dist, None].iter().copied()
47    }
48
49    pub fn purpose(&self) -> String {
50        use Profile::*;
51        match self {
52            Library => "Contribute to the standard library",
53            Compiler => "Contribute to the compiler itself",
54            Tools => "Contribute to tools which depend on the compiler, but do not modify it directly (e.g. rustdoc, clippy, miri)",
55            Dist => "Install Rust from source",
56            None => "Do not modify `config.toml`"
57        }
58        .to_string()
59    }
60
61    pub fn all_for_help(indent: &str) -> String {
62        let mut out = String::new();
63        for choice in Profile::all() {
64            writeln!(&mut out, "{}{}: {}", indent, choice, choice.purpose()).unwrap();
65        }
66        out
67    }
68
69    pub fn as_str(&self) -> &'static str {
70        match self {
71            Profile::Compiler => "compiler",
72            Profile::Library => "library",
73            Profile::Tools => "tools",
74            Profile::Dist => "dist",
75            Profile::None => "none",
76        }
77    }
78}
79
80impl FromStr for Profile {
81    type Err = String;
82
83    fn from_str(s: &str) -> Result<Self, Self::Err> {
84        match s {
85            "lib" | "library" => Ok(Profile::Library),
86            "compiler" => Ok(Profile::Compiler),
87            "maintainer" | "dist" | "user" => Ok(Profile::Dist),
88            "tools" | "tool" | "rustdoc" | "clippy" | "miri" | "rustfmt" | "rls" => {
89                Ok(Profile::Tools)
90            }
91            "none" => Ok(Profile::None),
92            "llvm" | "codegen" => Err("the \"llvm\" and \"codegen\" profiles have been removed,\
93                use \"compiler\" instead which has the same functionality"
94                .to_string()),
95            _ => Err(format!("unknown profile: '{s}'")),
96        }
97    }
98}
99
100impl fmt::Display for Profile {
101    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
102        f.write_str(self.as_str())
103    }
104}
105
106impl Step for Profile {
107    type Output = ();
108    const DEFAULT: bool = true;
109
110    fn should_run(mut run: ShouldRun<'_>) -> ShouldRun<'_> {
111        for choice in Profile::all() {
112            run = run.alias(choice.as_str());
113        }
114        run
115    }
116
117    fn make_run(run: RunConfig<'_>) {
118        if run.builder.config.dry_run() {
119            return;
120        }
121
122        let path = &run.builder.config.config.clone().unwrap_or(PathBuf::from("config.toml"));
123        if path.exists() {
124            eprintln!();
125            eprintln!(
126                "ERROR: you asked for a new config file, but one already exists at `{}`",
127                t!(path.canonicalize()).display()
128            );
129
130            match prompt_user(
131                "Do you wish to override the existing configuration (which will allow the setup process to continue)?: [y/N]",
132            ) {
133                Ok(Some(PromptResult::Yes)) => {
134                    t!(fs::remove_file(path));
135                }
136                _ => {
137                    println!("Exiting.");
138                    crate::exit!(1);
139                }
140            }
141        }
142
143        // for Profile, `run.paths` will have 1 and only 1 element
144        // this is because we only accept at most 1 path from user input.
145        // If user calls `x.py setup` without arguments, the interactive TUI
146        // will guide user to provide one.
147        let profile = if run.paths.len() > 1 {
148            // HACK: `builder` runs this step with all paths if no path was passed.
149            t!(interactive_path())
150        } else {
151            run.paths
152                .first()
153                .unwrap()
154                .assert_single_path()
155                .path
156                .as_path()
157                .as_os_str()
158                .to_str()
159                .unwrap()
160                .parse()
161                .unwrap()
162        };
163
164        run.builder.ensure(profile);
165    }
166
167    fn run(self, builder: &Builder<'_>) {
168        setup(&builder.build.config, self);
169    }
170}
171
172pub fn setup(config: &Config, profile: Profile) {
173    let suggestions: &[&str] = match profile {
174        Profile::Compiler | Profile::None => &["check", "build", "test"],
175        Profile::Tools => &[
176            "check",
177            "build",
178            "test tests/rustdoc*",
179            "test src/tools/clippy",
180            "test src/tools/miri",
181            "test src/tools/rustfmt",
182        ],
183        Profile::Library => &["check", "build", "test library/std", "doc"],
184        Profile::Dist => &["dist", "build"],
185    };
186
187    println!();
188
189    println!("To get started, try one of the following commands:");
190    for cmd in suggestions {
191        println!("- `x.py {cmd}`");
192    }
193
194    if profile != Profile::Dist {
195        println!(
196            "For more suggestions, see https://rustc-dev-guide.rust-lang.org/building/suggested.html"
197        );
198    }
199
200    if profile == Profile::Tools {
201        eprintln!();
202        eprintln!(
203            "NOTE: the `tools` profile sets up the `stage2` toolchain (use \
204            `rustup toolchain link 'name' build/host/stage2` to use rustc)"
205        )
206    }
207
208    let path = &config.config.clone().unwrap_or(PathBuf::from("config.toml"));
209    setup_config_toml(path, profile, config);
210}
211
212fn setup_config_toml(path: &Path, profile: Profile, config: &Config) {
213    if profile == Profile::None {
214        return;
215    }
216
217    let latest_change_id = CONFIG_CHANGE_HISTORY.last().unwrap().change_id;
218    let settings = format!(
219        "# Includes one of the default files in {PROFILE_DIR}\n\
220    profile = \"{profile}\"\n\
221    change-id = {latest_change_id}\n"
222    );
223
224    t!(fs::write(path, settings));
225
226    let include_path = profile.include_path(&config.src);
227    println!("`x.py` will now use the configuration at {}", include_path.display());
228}
229
230/// Creates a toolchain link for stage1 using `rustup`
231#[derive(Clone, Debug, Eq, PartialEq, Hash)]
232pub struct Link;
233impl Step for Link {
234    type Output = ();
235    const DEFAULT: bool = true;
236
237    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
238        run.alias("link")
239    }
240
241    fn make_run(run: RunConfig<'_>) {
242        if run.builder.config.dry_run() {
243            return;
244        }
245        if let [cmd] = &run.paths[..] {
246            if cmd.assert_single_path().path.as_path().as_os_str() == "link" {
247                run.builder.ensure(Link);
248            }
249        }
250    }
251    fn run(self, builder: &Builder<'_>) -> Self::Output {
252        let config = &builder.config;
253
254        if config.dry_run() {
255            return;
256        }
257
258        if !rustup_installed(builder) {
259            println!("WARNING: `rustup` is not installed; Skipping `stage1` toolchain linking.");
260            return;
261        }
262
263        let stage_path =
264            ["build", config.build.rustc_target_arg(), "stage1"].join(MAIN_SEPARATOR_STR);
265
266        if stage_dir_exists(&stage_path[..]) && !config.dry_run() {
267            attempt_toolchain_link(builder, &stage_path[..]);
268        }
269    }
270}
271
272fn rustup_installed(builder: &Builder<'_>) -> bool {
273    let mut rustup = command("rustup");
274    rustup.arg("--version");
275
276    rustup.allow_failure().run_always().run_capture_stdout(builder).is_success()
277}
278
279fn stage_dir_exists(stage_path: &str) -> bool {
280    match fs::create_dir(stage_path) {
281        Ok(_) => true,
282        Err(_) => Path::new(&stage_path).exists(),
283    }
284}
285
286fn attempt_toolchain_link(builder: &Builder<'_>, stage_path: &str) {
287    if toolchain_is_linked(builder) {
288        return;
289    }
290
291    if !ensure_stage1_toolchain_placeholder_exists(stage_path) {
292        eprintln!(
293            "Failed to create a template for stage 1 toolchain or confirm that it already exists"
294        );
295        return;
296    }
297
298    if try_link_toolchain(builder, stage_path) {
299        println!(
300            "Added `stage1` rustup toolchain; try `cargo +stage1 build` on a separate rust project to run a newly-built toolchain"
301        );
302    } else {
303        eprintln!("`rustup` failed to link stage 1 build to `stage1` toolchain");
304        eprintln!(
305            "To manually link stage 1 build to `stage1` toolchain, run:\n
306            `rustup toolchain link stage1 {}`",
307            &stage_path
308        );
309    }
310}
311
312fn toolchain_is_linked(builder: &Builder<'_>) -> bool {
313    match command("rustup")
314        .allow_failure()
315        .args(["toolchain", "list"])
316        .run_capture_stdout(builder)
317        .stdout_if_ok()
318    {
319        Some(toolchain_list) => {
320            if !toolchain_list.contains("stage1") {
321                return false;
322            }
323            // The toolchain has already been linked.
324            println!(
325                "`stage1` toolchain already linked; not attempting to link `stage1` toolchain"
326            );
327        }
328        None => {
329            // In this case, we don't know if the `stage1` toolchain has been linked;
330            // but `rustup` failed, so let's not go any further.
331            println!(
332                "`rustup` failed to list current toolchains; not attempting to link `stage1` toolchain"
333            );
334        }
335    }
336    true
337}
338
339fn try_link_toolchain(builder: &Builder<'_>, stage_path: &str) -> bool {
340    command("rustup")
341        .args(["toolchain", "link", "stage1", stage_path])
342        .run_capture_stdout(builder)
343        .is_success()
344}
345
346fn ensure_stage1_toolchain_placeholder_exists(stage_path: &str) -> bool {
347    let pathbuf = PathBuf::from(stage_path);
348
349    if fs::create_dir_all(pathbuf.join("lib")).is_err() {
350        return false;
351    };
352
353    let pathbuf = pathbuf.join("bin");
354    if fs::create_dir_all(&pathbuf).is_err() {
355        return false;
356    };
357
358    let pathbuf = pathbuf.join(format!("rustc{EXE_SUFFIX}"));
359
360    if pathbuf.exists() {
361        return true;
362    }
363
364    // Take care not to overwrite the file
365    let result = File::options().append(true).create(true).open(&pathbuf);
366    if result.is_err() {
367        return false;
368    }
369
370    true
371}
372
373// Used to get the path for `Subcommand::Setup`
374pub fn interactive_path() -> io::Result<Profile> {
375    fn abbrev_all() -> impl Iterator<Item = ((String, String), Profile)> {
376        ('a'..)
377            .zip(1..)
378            .map(|(letter, number)| (letter.to_string(), number.to_string()))
379            .zip(Profile::all())
380    }
381
382    fn parse_with_abbrev(input: &str) -> Result<Profile, String> {
383        let input = input.trim().to_lowercase();
384        for ((letter, number), profile) in abbrev_all() {
385            if input == letter || input == number {
386                return Ok(profile);
387            }
388        }
389        input.parse()
390    }
391
392    println!("Welcome to the Rust project! What do you want to do with x.py?");
393    for ((letter, _), profile) in abbrev_all() {
394        println!("{}) {}: {}", letter, profile, profile.purpose());
395    }
396    let template = loop {
397        print!(
398            "Please choose one ({}): ",
399            abbrev_all().map(|((l, _), _)| l).collect::<Vec<_>>().join("/")
400        );
401        io::stdout().flush()?;
402        let mut input = String::new();
403        io::stdin().read_line(&mut input)?;
404        if input.is_empty() {
405            eprintln!("EOF on stdin, when expecting answer to question.  Giving up.");
406            crate::exit!(1);
407        }
408        break match parse_with_abbrev(&input) {
409            Ok(profile) => profile,
410            Err(err) => {
411                eprintln!("ERROR: {err}");
412                eprintln!("NOTE: press Ctrl+C to exit");
413                continue;
414            }
415        };
416    };
417    Ok(template)
418}
419
420#[derive(PartialEq)]
421enum PromptResult {
422    Yes,   // y/Y/yes
423    No,    // n/N/no
424    Print, // p/P/print
425}
426
427/// Prompt a user for a answer, looping until they enter an accepted input or nothing
428fn prompt_user(prompt: &str) -> io::Result<Option<PromptResult>> {
429    let mut input = String::new();
430    loop {
431        print!("{prompt} ");
432        io::stdout().flush()?;
433        input.clear();
434        io::stdin().read_line(&mut input)?;
435        match input.trim().to_lowercase().as_str() {
436            "y" | "yes" => return Ok(Some(PromptResult::Yes)),
437            "n" | "no" => return Ok(Some(PromptResult::No)),
438            "p" | "print" => return Ok(Some(PromptResult::Print)),
439            "" => return Ok(None),
440            _ => {
441                eprintln!("ERROR: unrecognized option '{}'", input.trim());
442                eprintln!("NOTE: press Ctrl+C to exit");
443            }
444        };
445    }
446}
447
448/// Installs `src/etc/pre-push.sh` as a Git hook
449#[derive(Clone, Debug, Eq, PartialEq, Hash)]
450pub struct Hook;
451
452impl Step for Hook {
453    type Output = ();
454    const DEFAULT: bool = true;
455
456    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
457        run.alias("hook")
458    }
459
460    fn make_run(run: RunConfig<'_>) {
461        if let [cmd] = &run.paths[..] {
462            if cmd.assert_single_path().path.as_path().as_os_str() == "hook" {
463                run.builder.ensure(Hook);
464            }
465        }
466    }
467
468    fn run(self, builder: &Builder<'_>) -> Self::Output {
469        let config = &builder.config;
470
471        if config.dry_run() || !config.rust_info.is_managed_git_subrepository() {
472            return;
473        }
474
475        t!(install_git_hook_maybe(builder, config));
476    }
477}
478
479// install a git hook to automatically run tidy, if they want
480fn install_git_hook_maybe(builder: &Builder<'_>, config: &Config) -> io::Result<()> {
481    let git = helpers::git(Some(&config.src))
482        .args(["rev-parse", "--git-common-dir"])
483        .run_capture(builder)
484        .stdout();
485    let git = PathBuf::from(git.trim());
486    let hooks_dir = git.join("hooks");
487    let dst = hooks_dir.join("pre-push");
488    if dst.exists() {
489        // The git hook has already been set up, or the user already has a custom hook.
490        return Ok(());
491    }
492
493    println!(
494        "\nRust's CI will automatically fail if it doesn't pass `tidy`, the internal tool for ensuring code quality.
495If you'd like, x.py can install a git hook for you that will automatically run `test tidy` before
496pushing your code to ensure your code is up to par. If you decide later that this behavior is
497undesirable, simply delete the `pre-push` file from .git/hooks."
498    );
499
500    if prompt_user("Would you like to install the git hook?: [y/N]")? != Some(PromptResult::Yes) {
501        println!("Ok, skipping installation!");
502        return Ok(());
503    }
504    if !hooks_dir.exists() {
505        // We need to (try to) create the hooks directory first.
506        let _ = fs::create_dir(hooks_dir);
507    }
508    let src = config.src.join("src").join("etc").join("pre-push.sh");
509    match fs::hard_link(src, &dst) {
510        Err(e) => {
511            eprintln!(
512                "ERROR: could not create hook {}: do you already have the git hook installed?\n{}",
513                dst.display(),
514                e
515            );
516            return Err(e);
517        }
518        Ok(_) => println!("Linked `src/etc/pre-push.sh` to `.git/hooks/pre-push`"),
519    };
520    Ok(())
521}
522
523/// Handles editor-specific setup differences
524#[derive(Clone, Debug, Eq, PartialEq)]
525enum EditorKind {
526    Vscode,
527    Vim,
528    Emacs,
529    Helix,
530}
531
532impl EditorKind {
533    fn prompt_user() -> io::Result<Option<EditorKind>> {
534        let prompt_str = "Available editors:
5351. vscode
5362. vim
5373. emacs
5384. helix
539
540Select which editor you would like to set up [default: None]: ";
541
542        let mut input = String::new();
543        loop {
544            print!("{}", prompt_str);
545            io::stdout().flush()?;
546            input.clear();
547            io::stdin().read_line(&mut input)?;
548            match input.trim().to_lowercase().as_str() {
549                "1" | "vscode" => return Ok(Some(EditorKind::Vscode)),
550                "2" | "vim" => return Ok(Some(EditorKind::Vim)),
551                "3" | "emacs" => return Ok(Some(EditorKind::Emacs)),
552                "4" | "helix" => return Ok(Some(EditorKind::Helix)),
553                "" => return Ok(None),
554                _ => {
555                    eprintln!("ERROR: unrecognized option '{}'", input.trim());
556                    eprintln!("NOTE: press Ctrl+C to exit");
557                }
558            };
559        }
560    }
561
562    /// A list of historical hashes of each LSP settings file
563    /// New entries should be appended whenever this is updated so we can detect
564    /// outdated vs. user-modified settings files.
565    fn hashes(&self) -> Vec<&str> {
566        match self {
567            EditorKind::Vscode | EditorKind::Vim => vec![
568                "ea67e259dedf60d4429b6c349a564ffcd1563cf41c920a856d1f5b16b4701ac8",
569                "56e7bf011c71c5d81e0bf42e84938111847a810eee69d906bba494ea90b51922",
570                "af1b5efe196aed007577899db9dae15d6dbc923d6fa42fa0934e68617ba9bbe0",
571                "3468fea433c25fff60be6b71e8a215a732a7b1268b6a83bf10d024344e140541",
572                "47d227f424bf889b0d899b9cc992d5695e1b78c406e183cd78eafefbe5488923",
573                "b526bd58d0262dd4dda2bff5bc5515b705fb668a46235ace3e057f807963a11a",
574                "828666b021d837a33e78d870b56d34c88a5e2c85de58b693607ec574f0c27000",
575                "811fb3b063c739d261fd8590dd30242e117908f5a095d594fa04585daa18ec4d",
576                "4eecb58a2168b252077369da446c30ed0e658301efe69691979d1ef0443928f4",
577                "c394386e6133bbf29ffd32c8af0bb3d4aac354cba9ee051f29612aa9350f8f8d",
578            ],
579            EditorKind::Emacs => vec![
580                "51068d4747a13732440d1a8b8f432603badb1864fa431d83d0fd4f8fa57039e0",
581                "d29af4d949bbe2371eac928a3c31cf9496b1701aa1c45f11cd6c759865ad5c45",
582            ],
583            EditorKind::Helix => {
584                vec!["2d3069b8cf1b977e5d4023965eb6199597755e6c96c185ed5f2854f98b83d233"]
585            }
586        }
587    }
588
589    fn settings_path(&self, config: &Config) -> PathBuf {
590        config.src.join(self.settings_short_path())
591    }
592
593    fn settings_short_path(&self) -> PathBuf {
594        self.settings_folder().join(match self {
595            EditorKind::Vscode => "settings.json",
596            EditorKind::Vim => "coc-settings.json",
597            EditorKind::Emacs => ".dir-locals.el",
598            EditorKind::Helix => "languages.toml",
599        })
600    }
601
602    fn settings_folder(&self) -> PathBuf {
603        match self {
604            EditorKind::Vscode => PathBuf::from(".vscode"),
605            EditorKind::Vim => PathBuf::from(".vim"),
606            EditorKind::Emacs => PathBuf::new(),
607            EditorKind::Helix => PathBuf::from(".helix"),
608        }
609    }
610
611    fn settings_template(&self) -> &str {
612        match self {
613            EditorKind::Vscode | EditorKind::Vim => {
614                include_str!("../../../../etc/rust_analyzer_settings.json")
615            }
616            EditorKind::Emacs => include_str!("../../../../etc/rust_analyzer_eglot.el"),
617            EditorKind::Helix => include_str!("../../../../etc/rust_analyzer_helix.toml"),
618        }
619    }
620
621    fn backup_extension(&self) -> String {
622        format!("{}.bak", self.settings_short_path().extension().unwrap().to_str().unwrap())
623    }
624}
625
626/// Sets up or displays the LSP config for one of the supported editors
627#[derive(Clone, Debug, Eq, PartialEq, Hash)]
628pub struct Editor;
629
630impl Step for Editor {
631    type Output = ();
632    const DEFAULT: bool = true;
633
634    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
635        run.alias("editor")
636    }
637
638    fn make_run(run: RunConfig<'_>) {
639        if run.builder.config.dry_run() {
640            return;
641        }
642        if let [cmd] = &run.paths[..] {
643            if cmd.assert_single_path().path.as_path().as_os_str() == "editor" {
644                run.builder.ensure(Editor);
645            }
646        }
647    }
648
649    fn run(self, builder: &Builder<'_>) -> Self::Output {
650        let config = &builder.config;
651        if config.dry_run() {
652            return;
653        }
654        match EditorKind::prompt_user() {
655            Ok(editor_kind) => {
656                if let Some(editor_kind) = editor_kind {
657                    while !t!(create_editor_settings_maybe(config, editor_kind.clone())) {}
658                } else {
659                    println!("Ok, skipping editor setup!");
660                }
661            }
662            Err(e) => eprintln!("Could not determine the editor: {e}"),
663        }
664    }
665}
666
667/// Create the recommended editor LSP config file for rustc development, or just print it
668/// If this method should be re-called, it returns `false`.
669fn create_editor_settings_maybe(config: &Config, editor: EditorKind) -> io::Result<bool> {
670    let hashes = editor.hashes();
671    let (current_hash, historical_hashes) = hashes.split_last().unwrap();
672    let settings_path = editor.settings_path(config);
673    let settings_short_path = editor.settings_short_path();
674    let settings_filename = settings_short_path.to_str().unwrap();
675    // If None, no settings file exists
676    // If Some(true), is a previous version of settings.json
677    // If Some(false), is not a previous version (i.e. user modified)
678    // If it's up to date we can just skip this
679    let mut mismatched_settings = None;
680    if let Ok(current) = fs::read_to_string(&settings_path) {
681        let mut hasher = sha2::Sha256::new();
682        hasher.update(&current);
683        let hash = hex_encode(hasher.finalize().as_slice());
684        if hash == *current_hash {
685            return Ok(true);
686        } else if historical_hashes.contains(&hash.as_str()) {
687            mismatched_settings = Some(true);
688        } else {
689            mismatched_settings = Some(false);
690        }
691    }
692    println!(
693        "\nx.py can automatically install the recommended `{settings_filename}` file for rustc development"
694    );
695
696    match mismatched_settings {
697        Some(true) => {
698            eprintln!("WARNING: existing `{settings_filename}` is out of date, x.py will update it")
699        }
700        Some(false) => eprintln!(
701            "WARNING: existing `{settings_filename}` has been modified by user, x.py will back it up and replace it"
702        ),
703        _ => (),
704    }
705    let should_create = match prompt_user(&format!(
706        "Would you like to create/update `{settings_filename}`? (Press 'p' to preview values): [y/N]"
707    ))? {
708        Some(PromptResult::Yes) => true,
709        Some(PromptResult::Print) => false,
710        _ => {
711            println!("Ok, skipping settings!");
712            return Ok(true);
713        }
714    };
715    if should_create {
716        let settings_folder_path = config.src.join(editor.settings_folder());
717        if !settings_folder_path.exists() {
718            fs::create_dir(settings_folder_path)?;
719        }
720        let verb = match mismatched_settings {
721            // exists but outdated, we can replace this
722            Some(true) => "Updated",
723            // exists but user modified, back it up
724            Some(false) => {
725                // exists and is not current version or outdated, so back it up
726                let backup = settings_path.clone().with_extension(editor.backup_extension());
727                eprintln!(
728                    "WARNING: copying `{}` to `{}`",
729                    settings_path.file_name().unwrap().to_str().unwrap(),
730                    backup.file_name().unwrap().to_str().unwrap(),
731                );
732                fs::copy(&settings_path, &backup)?;
733                "Updated"
734            }
735            _ => "Created",
736        };
737        fs::write(&settings_path, editor.settings_template())?;
738        println!("{verb} `{}`", settings_filename);
739    } else {
740        println!("\n{}", editor.settings_template());
741    }
742    Ok(should_create)
743}