get latest x version from parsing cargo command

Cargo.lock

@@ -4814,9 +4814,9 @@ dependencies = [
 
 [[package]]
 name = "serde"
-version = "1.0.147"
+version = "1.0.152"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d193d69bae983fc11a79df82342761dfbf28a99fc8d203dca4c3c1b590948965"
+checksum = "bb7d1f0d3021d347a83e556fc4683dea2ea09d87bccdf88ff5c12545d89d5efb"
 dependencies = [
  "serde_derive",
 ]
@@ -4833,9 +4833,9 @@ dependencies = [
 
 [[package]]
 name = "serde_derive"
-version = "1.0.147"
+version = "1.0.152"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4f1d362ca8fc9c3e3a7484440752472d68a6caa98f1ab81d99b5dfe517cec852"
+checksum = "af487d118eecd09402d70a5d72551860e788df87b464af30e5ea6a38c75c541e"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -4853,9 +4853,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.85"
+version = "1.0.91"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e55a28e3aaef9d5ce0506d0a14dbba8054ddc7e499ef522dd8b26859ec9d4a44"
+checksum = "877c235533714907a8c2464236f5c4b2a17262ef1bd71f38f35ea592c8da6883"
 dependencies = [
  "indexmap",
  "itoa",
@@ -5133,9 +5133,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.102"
+version = "1.0.107"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fcd952facd492f9be3ef0d0b7032a6e442ee9b361d4acc2b1d0c4aaa5f613a1"
+checksum = "1f4064b5b16e03ae50984a5a8ed5d4f8803e6bc1fd170a3cda91a1be4b18e3f5"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -5310,6 +5310,7 @@ dependencies = [
  "miropt-test-tools",
  "regex",
  "semver",
+ "serde_json",
  "termcolor",
  "walkdir",
 ]

src/tools/tidy/Cargo.toml

@@ -12,6 +12,7 @@ lazy_static = "1"
 walkdir = "2"
 ignore = "0.4.18"
 semver = "1.0.14"
+serde_json = "1.0.91"
 termcolor = "1.1.3"
 
 [[bin]]

src/tools/tidy/src/x_version.rs

@@ -1,4 +1,5 @@
-use semver::{BuildMetadata, Prerelease, Version};
+use semver::Version;
+use serde_json::Value;
 use std::io::ErrorKind;
 use std::process::{Command, Stdio};
 
@@ -33,20 +34,47 @@ pub fn check(bad: &mut bool) {
     if output.status.success() {
         let version = String::from_utf8_lossy(&output.stdout);
         let version = Version::parse(version.trim_end()).unwrap();
-        let expected = Version {
+
-            major: 0,
+        if let Some(expected) = get_x_wrapper_version() {
-            minor: 1,
+            if version < expected {
-            patch: 0,
+                return tidy_error!(
-            pre: Prerelease::new("").unwrap(),
+                    bad,
-            build: BuildMetadata::EMPTY,
+                    "Current version of x is {version}, but the latest version is {expected}\nConsider updating to the newer version of x by running `cargo install --path src/tools/x`"
-        };
+                );
-        if version < expected {
+            }
+        } else {
             return tidy_error!(
                 bad,
-                "Current version of x is {version}, but the latest version is {expected}\nConsider updating to the newer version of x by running `cargo install --path src/tools/x`"
+                "Unable to parse the latest version of `x` at `src/tools/x/Cargo.toml`"
             );
         }
     } else {
         return tidy_error!(bad, "failed to check version of `x`: {}", output.status);
     }
 }
+
+// Parse latest version out of `x` Cargo.toml
+fn get_x_wrapper_version() -> Option<Version> {
+    let cmd = Command::new("cargo")
+        .arg("metadata")
+        .args(["--no-deps", "--format-version", "1", "--manifest-path", "src/tools/x/Cargo.toml"])
+        .stdout(Stdio::piped())
+        .spawn();
+
+    let child = match cmd {
+        Ok(child) => child,
+        Err(e) => {
+            println!("failed to get version of `x`: {}", e);
+            return None;
+        }
+    };
+
+    let cargo_output = child.wait_with_output().unwrap();
+    let cargo_output_str =
+        String::from_utf8(cargo_output.stdout).expect("Unable to parse `src/tools/x/Cargo.toml`");
+
+    let v: Value = serde_json::from_str(&cargo_output_str).unwrap();
+    let vesrion_str = &v["packages"][0]["version"].as_str()?;
+
+    Some(Version::parse(vesrion_str).unwrap())
+}