Move the readme_rendering table onto versions

Every row in versions had at most a single row in the `readme_rendering`
table, and the table had only a single column. There is no reason for
this table to live separately.

Author: sgrif

migrations/2017-09-23-210614_move_readme_rendering_onto_versions/down.sql

@@ -0,0 +1,9 @@
+CREATE TABLE readme_rendering (
+    version_id INTEGER NOT NULL PRIMARY KEY REFERENCES versions (id) ON DELETE CASCADE,
+    rendered_at TIMESTAMP NOT NULL
+);
+
+INSERT INTO readme_rendering (version_id, rendered_at)
+  SELECT id, readme_rendered_at FROM versions WHERE readme_rendered_at IS NOT NULL;
+
+ALTER TABLE versions DROP COLUMN readme_rendered_at;

migrations/2017-09-23-210614_move_readme_rendering_onto_versions/up.sql

@@ -0,0 +1,4 @@
+ALTER TABLE versions ADD COLUMN readme_rendered_at TIMESTAMP;
+UPDATE versions SET readme_rendered_at = readme_rendering.rendered_at
+  FROM readme_rendering WHERE readme_rendering.version_id = versions.id;
+DROP TABLE readme_rendering;

src/bin/render-readmes.rs

@@ -79,9 +79,8 @@ fn main() {
 
     let mut query = versions::table
         .inner_join(crates::table)
-        .left_join(readme_rendering::table)
-        .filter(readme_rendering::rendered_at.lt(older_than).or(
-            readme_rendering::rendered_at.is_null(),
+        .filter(versions::readme_rendered_at.lt(older_than).or(
+            versions::readme_rendered_at.is_null(),
         ))
         .select(versions::id)
         .into_boxed();

src/schema.rs

@@ -506,26 +506,6 @@ table! {
     }
 }
 
-table! {
-    /// Representation of the `readme_rendering` table.
-    ///
-    /// (Automatically generated by Diesel.)
-    readme_rendering (version_id) {
-        /// The `version_id` column of the `readme_rendering` table.
-        ///
-        /// Its SQL type is `Int4`.
-        ///
-        /// (Automatically generated by Diesel.)
-        version_id -> Int4,
-        /// The `rendered_at` column of the `readme_rendering` table.
-        ///
-        /// Its SQL type is `Nullable<Timestamp>`.
-        ///
-        /// (Automatically generated by Diesel.)
-        rendered_at -> Nullable<Timestamp>,
-    }
-}
-
 table! {
     /// Representation of the `reserved_crate_names` table.
     ///
@@ -795,6 +775,12 @@ table! {
         ///
         /// (Automatically generated by Diesel.)
         license -> Nullable<Varchar>,
+        /// The `readme_rendered_at` column of the `versions` table.
+        ///
+        /// Its SQL type is `Nullable<Timestamp>`.
+        ///
+        /// (Automatically generated by Diesel.)
+        readme_rendered_at -> Nullable<Timestamp>,
     }
 }
 
@@ -815,6 +801,5 @@ joinable!(version_authors -> versions (version_id));
 joinable!(version_downloads -> versions (version_id));
 joinable!(crate_owners -> teams (owner_id));
 joinable!(crate_owners -> users (owner_id));
-joinable!(readme_rendering -> versions (version_id));
 joinable!(crate_owner_invitations -> crates (crate_id));
 joinable!(tokens -> emails (email_id));

src/version.rs

@@ -4,7 +4,6 @@ use conduit::{Request, Response};
 use conduit_router::RequestParams;
 use diesel;
 use diesel::pg::Pg;
-use diesel::pg::upsert::*;
 use diesel::prelude::*;
 use semver;
 use serde_json;
@@ -24,10 +23,6 @@ use util::errors::CargoError;
 use util::{RequestUtils, CargoResult, human};
 use license_exprs;
 
-// This is necessary to allow joining version to both crates and readme_rendering
-// in the render-readmes script.
-enable_multi_table_joins!(crates, readme_rendering);
-
 // Queryable has a custom implementation below
 #[derive(Clone, Identifiable, Associations, Debug)]
 #[belongs_to(Crate)]
@@ -76,15 +71,6 @@ pub struct VersionLinks {
     pub authors: String,
 }
 
-#[derive(Insertable, Identifiable, Queryable, Associations, Debug, Clone, Copy)]
-#[belongs_to(Version)]
-#[table_name = "readme_rendering"]
-#[primary_key(version_id)]
-struct ReadmeRendering {
-    version_id: i32,
-    rendered_at: Timespec,
-}
-
 impl Version {
     pub fn encodable(self, crate_name: &str) -> EncodableVersion {
         let Version {
@@ -143,22 +129,13 @@ impl Version {
         })
     }
 
-    pub fn record_readme_rendering(&self, conn: &PgConnection) -> CargoResult<()> {
-        let rendered = ReadmeRendering {
-            version_id: self.id,
-            rendered_at: ::now(),
-        };
+    pub fn record_readme_rendering(&self, conn: &PgConnection) -> QueryResult<usize> {
+        use schema::versions::dsl::readme_rendered_at;
+        use diesel::expression::now;
 
-        diesel::insert(&rendered.on_conflict(
-            readme_rendering::version_id,
-            do_update().set(readme_rendering::rendered_at.eq(
-                excluded(
-                    readme_rendering::rendered_at,
-                ),
-            )),
-        )).into(readme_rendering::table)
-            .execute(&*conn)?;
-        Ok(())
+        diesel::update(self)
+            .set(readme_rendered_at.eq(now.nullable()))
+            .execute(conn)
     }
 }
 
@@ -250,7 +227,17 @@ struct NewAuthor<'a> {
 }
 
 impl Queryable<versions::SqlType, Pg> for Version {
-    type Row = (i32, i32, String, Timespec, Timespec, i32, Option<String>, bool, Option<String>);
+    #[cfg_attr(feature = "clippy", allow(type_complexity))]
+    type Row = (i32,
+     i32,
+     String,
+     Timespec,
+     Timespec,
+     i32,
+     Option<String>,
+     bool,
+     Option<String>,
+     Option<Timespec>);
 
     fn build(row: Self::Row) -> Self {
         let features = row.6