Add updates.warn_cache_age config option (#492)

This is useful when the cache is managed externally, e.g. provisioned
from a Nix store path or by a package manager, where the directory's
mtime doesn't reflect the cache's real age, causing a spurious warning
on every invocation. Today the only way to silence it is `--quiet`,
which must be passed every call and hides all other output too.

docs/src/config_updates.md

@@ -30,6 +30,18 @@ auto_update = true
 auto_update_interval_hours = 24
 ```
 
+### `warn_cache_age`
+
+Controls when a warning is printed if the cache has not been updated in a while.
+By default, the warning is shown once the cache is older than 30 days. Set this
+to `"never"` to silence the warning. This is useful if, for some reason, the
+modification time does not reflect its actual age.
+
+```toml
+[updates]
+warn_cache_age = "never"
+```
+
 ## Download configuration
 
 ### `download_languages`

src/config.rs

@@ -228,6 +228,17 @@ fn default_archive_source() -> String {
     "https://github.com/tldr-pages/tldr/releases/latest/download".to_owned()
 }
 
+/// Controls when a warning about an outdated cache is printed.
+///
+/// Currently, the only nameable option is `"never"`. In the future, this may
+/// be extended to also accept a duration (e.g. `"60d"`), after which the
+/// warning should be shown.
+#[derive(Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "lowercase")]
+enum RawWarnCacheAge {
+    Never,
+}
+
 #[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
 struct RawUpdatesConfig {
     #[serde(default)]
@@ -240,6 +251,8 @@ struct RawUpdatesConfig {
     pub tls_backend: RawTlsBackend,
     #[serde(default)]
     pub download_languages: Option<Vec<String>>,
+    #[serde(default)]
+    pub warn_cache_age: Option<RawWarnCacheAge>,
 }
 
 impl Default for RawUpdatesConfig {
@@ -250,6 +263,7 @@ impl Default for RawUpdatesConfig {
             archive_source: default_archive_source(),
             tls_backend: RawTlsBackend::default(),
             download_languages: None,
+            warn_cache_age: None,
         }
     }
 }
@@ -380,6 +394,7 @@ pub struct UpdatesConfig<'a> {
     pub archive_source: &'a str,
     pub tls_backend: TlsBackend,
     pub download_languages: Vec<Language<'a>>,
+    pub warn_cache_age: Option<Duration>,
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -569,6 +584,10 @@ impl<'a> Config<'a> {
                 || search.languages.clone(),
                 |languages| languages.iter().map(|lang| Language(lang)).collect(),
             ),
+            warn_cache_age: match raw_config.updates.warn_cache_age {
+                None => Some(MAX_CACHE_AGE),
+                Some(RawWarnCacheAge::Never) => None,
+            },
         };
 
         let relative_path_root = config_file_path

src/main.rs

@@ -376,16 +376,18 @@ fn try_main(args: Cli, enable_styles: bool) -> Result<ExitCode> {
             return Ok(ExitCode::FAILURE);
         };
 
-        let age = cache.age()?;
-        if age > config::MAX_CACHE_AGE && !args.quiet {
-            print_warning(
-                enable_styles,
-                &format!(
-                    "The cache hasn't been updated for {} days.\n\
-                     You should probably run `tldr --update` soon.",
-                    age.as_secs() / 24 / 3600
-                ),
-            );
+        if let Some(max_cache_age) = config.updates.warn_cache_age {
+            let age = cache.age()?;
+            if age > max_cache_age && !args.quiet {
+                print_warning(
+                    enable_styles,
+                    &format!(
+                        "The cache hasn't been updated for {} days.\n\
+                         You should probably run `tldr --update` soon.",
+                        age.as_secs() / 24 / 3600
+                    ),
+                );
+            }
         }
 
         cache

tests/lib.rs

@@ -493,6 +493,26 @@ fn test_quiet_old_cache() {
         .stderr(contains("The cache hasn't been updated for ").not());
 }
 
+#[test]
+fn test_warn_cache_age_never() {
+    let testenv = TestEnv::new().install_default_cache();
+
+    filetime::set_file_mtime(
+        testenv.cache_dir().join(TLDR_PAGES_DIR),
+        filetime::FileTime::from_unix_time(1, 0),
+    )
+    .unwrap();
+
+    testenv.append_to_config("[updates]\nwarn_cache_age = \"never\"\n");
+
+    testenv
+        .command()
+        .args(["which"])
+        .assert()
+        .success()
+        .stderr(contains("The cache hasn't been updated for ").not());
+}
+
 #[cfg_attr(feature = "ignore-online-tests", ignore = "online test")]
 #[test]
 fn test_create_cache_directory_path() {