Auto merge of #8707 - dtolnay:plain, r=ehuss

Add plain message format for locate-project

Supersedes #8683, as recommended in #8683 (comment). This PR adds a flag `--message-format` to `cargo locate-project` with possible values `json` (default) and `plain`.

```console
$ cargo locate-project --message-format json
{"root":"/git/cargo/Cargo.toml"}

$ cargo locate-project --message-format plain
/git/cargo/Cargo.toml
```

Closes #8009.

Author: bors

src/bin/cargo/commands/locate_project.rs

@@ -1,11 +1,20 @@
 use crate::command_prelude::*;
+use anyhow::bail;
+use cargo::{drop_println, CargoResult};
 use serde::Serialize;
 
 pub fn cli() -> App {
     subcommand("locate-project")
         .about("Print a JSON representation of a Cargo.toml file's location")
         .arg(opt("quiet", "No output printed to stdout").short("q"))
         .arg_manifest_path()
+        .arg(
+            opt(
+                "message-format",
+                "Output representation [possible values: json, plain]",
+            )
+            .value_name("FMT"),
+        )
         .after_help("Run `cargo help locate-project` for more detailed information.\n")
 }
 
@@ -29,6 +38,29 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
 
     let location = ProjectLocation { root };
 
-    config.shell().print_json(&location);
+    match MessageFormat::parse(args)? {
+        MessageFormat::Json => config.shell().print_json(&location),
+        MessageFormat::Plain => drop_println!(config, "{}", location.root),
+    }
+
     Ok(())
 }
+
+enum MessageFormat {
+    Json,
+    Plain,
+}
+
+impl MessageFormat {
+    fn parse(args: &ArgMatches<'_>) -> CargoResult<Self> {
+        let fmt = match args.value_of("message-format") {
+            Some(fmt) => fmt,
+            None => return Ok(MessageFormat::Json),
+        };
+        match fmt.to_ascii_lowercase().as_str() {
+            "json" => Ok(MessageFormat::Json),
+            "plain" => Ok(MessageFormat::Plain),
+            s => bail!("invalid message format specifier: `{}`", s),
+        }
+    }
+}

src/doc/man/cargo-locate-project.md

@@ -21,6 +21,14 @@ workspace root.
 ### Display Options
 
 {{#options}}
+
+{{#option "`--message-format` _fmt_" }}
+The representation in which to print the project location. Valid values:
+
+- `json` (default): JSON object with the path under the key "root".
+- `plain`: Just the path.
+{{/option}}
+
 {{> options-display }}
 {{/options}}
 

src/doc/man/generated_txt/cargo-locate-project.txt

@@ -16,6 +16,14 @@ DESCRIPTION
 
 OPTIONS
    Display Options
+       --message-format fmt
+           The representation in which to print the project location. Valid
+           values:
+
+           o  json (default): JSON object with the path under the key "root".
+
+           o  plain: Just the path.
+
        -v, --verbose
            Use verbose output. May be specified twice for "very verbose" output
            which includes extra output such as dependency warnings and build

src/doc/src/commands/cargo-locate-project.md

@@ -21,6 +21,15 @@ workspace root.
 ### Display Options
 
 <dl>
+
+<dt class="option-term" id="option-cargo-locate-project---message-format"><a class="option-anchor" href="#option-cargo-locate-project---message-format"></a><code>--message-format</code> <em>fmt</em></dt>
+<dd class="option-desc">The representation in which to print the project location. Valid values:</p>
+<ul>
+<li><code>json</code> (default): JSON object with the path under the key &quot;root&quot;.</li>
+<li><code>plain</code>: Just the path.</li>
+</ul></dd>
+
+
 <dt class="option-term" id="option-cargo-locate-project--v"><a class="option-anchor" href="#option-cargo-locate-project--v"></a><code>-v</code></dt>
 <dt class="option-term" id="option-cargo-locate-project---verbose"><a class="option-anchor" href="#option-cargo-locate-project---verbose"></a><code>--verbose</code></dt>
 <dd class="option-desc">Use verbose output. May be specified twice for &quot;very verbose&quot; output which

src/etc/_cargo

@@ -160,7 +160,8 @@ _cargo() {
                         ;;
 
                 locate-project)
-                    _arguments -s -S $common $manifest
+                    _arguments -s -S $common $manifest \
+                        '--message-format=[specify output representation]:output representation [json]:(json plain)'
                         ;;
 
                 login)
@@ -367,8 +368,7 @@ _cargo_package_names() {
 # Extracts the values of "name" from the array given in $1 and shows them as
 # command line options for completion
 _cargo_names_from_array() {
-    # strip json from the path
-    local manifest=${${${"$(cargo locate-project)"}%\"\}}##*\"}
+    local manifest=$(cargo locate-project --message-format plain)
     if [[ -z $manifest ]]; then
         return 0
     fi

src/etc/cargo.bashcomp.sh

@@ -59,7 +59,7 @@ _cargo()
 	local opt__help="$opt_help"
 	local opt__init="$opt_common $opt_lock --bin --lib --name --vcs --edition --registry"
 	local opt__install="$opt_common $opt_feat $opt_jobs $opt_lock $opt_force --bin --bins --branch --debug --example --examples --git --list --path --rev --root --tag --version --registry --target --profile --no-track"
-	local opt__locate_project="$opt_common $opt_mani $opt_lock"
+	local opt__locate_project="$opt_common $opt_mani $opt_lock --message-format"
 	local opt__login="$opt_common $opt_lock --registry"
 	local opt__metadata="$opt_common $opt_feat $opt_mani $opt_lock --format-version=1 --no-deps --filter-platform"
 	local opt__new="$opt_common $opt_lock --vcs --bin --lib --name --edition --registry"
@@ -155,9 +155,7 @@ complete -F _cargo cargo
 __cargo_commands=$(cargo --list 2>/dev/null | awk 'NR>1 {print $1}')
 
 _locate_manifest(){
-	local manifest=`cargo locate-project 2>/dev/null`
-	# regexp-replace manifest '\{"root":"|"\}' ''
-	echo ${manifest:9:${#manifest}-11}
+	cargo locate-project --message-format plain 2>/dev/null
 }
 
 # Extracts the values of "name" from the array given in $1 and shows them as

src/etc/man/cargo-locate-project.1

@@ -16,6 +16,19 @@ workspace root.
 .SH "OPTIONS"
 .SS "Display Options"
 .sp
+\fB\-\-message\-format\fR \fIfmt\fR
+.RS 4
+The representation in which to print the project location. Valid values:
+.sp
+.RS 4
+\h'-04'\(bu\h'+02'\fBjson\fR (default): JSON object with the path under the key "root".
+.RE
+.sp
+.RS 4
+\h'-04'\(bu\h'+02'\fBplain\fR: Just the path.
+.RE
+.RE
+.sp
 \fB\-v\fR, 
 \fB\-\-verbose\fR
 .RS 4

tests/testsuite/locate_project.rs

@@ -14,3 +14,23 @@ fn simple() {
         ))
         .run();
 }
+
+#[cargo_test]
+fn message_format() {
+    let p = project().build();
+    let root_manifest_path = p.root().join("Cargo.toml");
+    let root_str = root_manifest_path.to_str().unwrap();
+
+    p.cargo("locate-project --message-format plain")
+        .with_stdout(root_str)
+        .run();
+
+    p.cargo("locate-project --message-format json")
+        .with_stdout(format!(r#"{{"root":"{}"}}"#, root_str))
+        .run();
+
+    p.cargo("locate-project --message-format cryptic")
+        .with_stderr("error: invalid message format specifier: `cryptic`")
+        .with_status(101)
+        .run();
+}