Check minimum CLI version on login

Cargo.toml

@@ -22,6 +22,7 @@ rpassword = "7.4.0"
 reqwest = { version = "0.12.20", default-features = false, features = ["json", "rustls-tls"] }
 serde = { version = "1.0.219", features = ["derive"] }
 serde_json = "1.0.140"
+semver = "1.0.26"
 tokio = { version = "1.45.1", features = ["macros", "rt-multi-thread"] }
 toml = "0.8.23"
 url = "2.5.4"

src/api.rs

@@ -282,6 +282,8 @@ pub struct UserWithToken {
 pub struct SystemInfo {
     pub version: VersionInfo,
     pub min_app_version: VersionInfo,
+    #[serde(default)]
+    pub min_cli_version: Option<VersionInfo>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -302,6 +304,11 @@ impl VersionInfo {
             _ => format!("{}.{}.{}", self.major, self.minor, self.patch),
         }
     }
+
+    pub fn semver(&self) -> Result<semver::Version> {
+        semver::Version::parse(&self.display())
+            .with_context(|| format!("invalid version returned by server: {}", self.display()))
+    }
 }
 
 #[derive(Debug, Default)]
@@ -435,4 +442,16 @@ mod tests {
             "http://localhost:3000/"
         );
     }
+
+    #[test]
+    fn parses_prerelease_versions() {
+        let version = VersionInfo {
+            major: 1,
+            minor: 2,
+            patch: 3,
+            pre: Some("rc.1".to_owned()),
+        };
+
+        assert_eq!(version.semver().unwrap().to_string(), "1.2.3-rc.1");
+    }
 }

src/main.rs

@@ -5,6 +5,7 @@ mod player;
 
 use anyhow::{Context, Result, bail};
 use clap::{Args, Parser, Subcommand};
+use semver::Version;
 use std::io::{self, Write};
 
 use crate::{
@@ -215,6 +216,7 @@ async fn login(args: LoginArgs) -> Result<()> {
     };
 
     let client = ApiClient::new(&server, None)?;
+    ensure_supported_cli_version(&client).await?;
     let response = client.login(&email, &password).await?;
 
     let config = Config {
@@ -237,6 +239,25 @@ async fn login(args: LoginArgs) -> Result<()> {
     Ok(())
 }
 
+async fn ensure_supported_cli_version(client: &ApiClient) -> Result<()> {
+    let Some(minimum) = client.system().await?.min_cli_version else {
+        return Ok(());
+    };
+    let current = Version::parse(env!("CARGO_PKG_VERSION"))
+        .expect("CARGO_PKG_VERSION must be a valid semantic version");
+    let minimum_version = minimum.semver()?;
+
+    if current < minimum_version {
+        bail!(
+            "this server requires Black Candy CLI {} or later; you are running {}. Please upgrade and try again.",
+            minimum.display(),
+            current
+        );
+    }
+
+    Ok(())
+}
+
 fn prompt_line(prompt: &str) -> Result<String> {
     print!("{prompt}");
     io::stdout().flush()?;
@@ -274,6 +295,9 @@ async fn run_authenticated(command: Command, client: ApiClient) -> Result<()> {
             } else {
                 println!("Server: {}", system.version.display());
                 println!("Minimum app version: {}", system.min_app_version.display());
+                if let Some(minimum) = system.min_cli_version {
+                    println!("Minimum CLI version: {}", minimum.display());
+                }
             }
         }
         Command::Search { query, json } => {