Warn users if they attempt to use rustc-timing as a database

Author: Mark-Simulacrum

site/src/bin/ingest.rs

@@ -43,10 +43,11 @@ fn deserialize_path(path: &Path) -> Res {
 }
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let db = site::db::open("data", true);
+    let dir = std::env::args().nth(1).expect("database as first arg");
+    let db = site::db::open(&dir, true);
     let mut index = site::db::Index::load(&db);
 
-    let paths = std::env::args().skip(1).collect::<Vec<_>>();
+    let paths = std::env::args().skip(2).collect::<Vec<_>>();
     let paths_count = paths.len();
     let mut last = std::time::Instant::now();
     for (idx, path) in paths.into_iter().enumerate() {

site/src/load.rs

@@ -151,6 +151,26 @@ impl InputData {
 
     /// Initialize `InputData from the file system.
     pub fn from_fs(db: &str) -> anyhow::Result<InputData> {
+        if std::path::Path::new(db).join("times").exists() {
+            eprintln!("It looks like you're running the site off of the old data format");
+            eprintln!(
+                "Please run the ingestion script pointing at a different directory, like so:"
+            );
+            eprintln!(
+                "    find rustc-timing/times/ -type f | xargs ./target/release/ingest database"
+            );
+            eprintln!();
+            eprintln!("And optionally follow up by shrinking the database:");
+            eprintln!("    ./target/release/compact database");
+            eprintln!("");
+            eprintln!("You can run the ingestion script repeatedly over all the files,");
+            eprintln!("or you can run it on just some newly collected data.");
+            eprintln!(
+                "The ingestion script must not be run in parallel with the site (it should error)."
+            );
+            std::process::exit(1);
+        }
+
         let config = if let Ok(s) = fs::read_to_string("site-config.toml") {
             toml::from_str(&s)?
         } else {