Make --ttl a required argument

src/main.rs

@@ -5,6 +5,7 @@ use std::process::{Command, exit, Stdio};
 use std::time::Duration;
 
 use anyhow::{Context, Result};
+use clap::error::{ContextKind, ContextValue, ErrorKind};
 use clap::Parser;
 
 use bkt::{CommandDesc, Bkt};
@@ -136,7 +137,7 @@ struct Cli {
     command: Vec<OsString>,
 
     /// Duration the cached result will be valid for
-    #[arg(long, value_name = "DURATION", default_value = "60s", visible_alias = "time-to-live", env = "BKT_TTL")]
+    #[arg(long, value_name = "DURATION", visible_alias = "time-to-live", env = "BKT_TTL")]
     ttl: humantime::Duration,
 
     /// Duration after which the result will be asynchronously refreshed
@@ -186,7 +187,19 @@ struct Cli {
 }
 
 fn main() {
-    let cli = Cli::parse();
+    // TODO remove this suggestion in 0.9.0
+    let mut cli = Cli::try_parse();
+    if let Err(err) = cli.as_mut() {
+        if matches!(err.kind(), ErrorKind::MissingRequiredArgument) {
+            // https://github.com/clap-rs/clap/discussions/5318
+            err.insert(ContextKind::Suggested, ContextValue::StyledStrs(vec![[
+                "Prior to 0.8.0 --ttl was optional, and defaulted to 60 seconds.",
+                "To preserve this behavior pass `--ttl=1m` or set `BKT_TTL=1m` in your environment."
+            ].join(" ").into()]));
+        }
+        err.exit();
+    }
+    let cli = cli.expect("Not Err");
 
     match run(cli) {
         Ok(code) => exit(code),

tests/cli.rs

@@ -32,6 +32,8 @@ mod cli {
         }
         assert!(path.exists(), "Could not find bkt binary in {:?}", dir);
         let mut bkt = Command::new(&path);
+        // Set a TTL here rather than in every test - tests that care about the TTL should override
+        bkt.env("BKT_TTL", "5s");
         bkt.env("BKT_TMPDIR", cache_dir.as_ref().as_os_str());
         bkt
     }
@@ -116,7 +118,7 @@ mod cli {
     fn help() {
         let dir = TestDir::temp();
         let out = succeed(bkt(dir.path("cache")).arg("--help"));
-        assert!(out.contains("bkt [OPTIONS] -- <COMMAND>..."));
+        assert!(out.contains("bkt [OPTIONS] --ttl <DURATION> -- <COMMAND>..."), "Was:\n---\n{}\n---", out);
     }
 
     #[test]
@@ -142,16 +144,16 @@ mod cli {
         let dir = TestDir::temp();
         let file = dir.path("file");
         let args = ["--", "bash", "-c", COUNT_INVOCATIONS, "arg0", file.to_str().unwrap()];
-        let first_result = succeed(bkt(dir.path("cache")).args(args));
+        let first_result = succeed(bkt(dir.path("cache")).arg("--ttl=1m").args(args));
         assert_eq!(first_result, "1");
 
         // Slightly stale is still cached
         make_dir_stale(dir.path("cache"), Duration::from_secs(10)).unwrap();
-        let subsequent_result = succeed(bkt(dir.path("cache")).args(args));
+        let subsequent_result = succeed(bkt(dir.path("cache")).arg("--ttl=1m").args(args));
         assert_eq!(first_result, subsequent_result);
 
         make_dir_stale(dir.path("cache"), Duration::from_secs(120)).unwrap();
-        let after_stale_result = succeed(bkt(dir.path("cache")).args(args));
+        let after_stale_result = succeed(bkt(dir.path("cache")).arg("--ttl=1m").args(args));
         assert_eq!(after_stale_result, "2");
 
         // Respects BKT_TTL env var (other tests cover --ttl)