Include inferred joinable! in diesel print-schema

This was a pretty straightforward addition. I've not included an
explicit test that the filtering is applied, or that the unsafe
constraints are removed here. It may be worth more exhaustively testing
this.

Author: sgrif

diesel_cli/src/print_schema.rs

@@ -25,12 +25,20 @@ pub fn run_print_schema(
     schema_name: Option<&str>,
     filtering: &Filtering
 ) -> Result<(), Box<Error>> {
-    let table_data = load_table_names(database_url, schema_name)?
+    let table_names = load_table_names(database_url, schema_name)?
         .into_iter()
         .filter(|t| !filtering.should_ignore_table(t))
+        .collect::<Vec<_>>();
+    let foreign_keys = load_foreign_key_constraints(database_url, schema_name)?;
+    let foreign_keys = remove_unsafe_foreign_keys_for_codegen(
+        database_url,
+        &foreign_keys,
+        &table_names,
+    );
+    let table_data = table_names.into_iter()
         .map(|t| load_table_data(database_url, t))
         .collect::<Result<_, Box<Error>>>()?;
-    let definitions = TableDefinitions(table_data);
+    let definitions = TableDefinitions(table_data, foreign_keys);
 
     if let Some(schema_name) = schema_name {
         print!("{}", ModuleDefinition(schema_name, definitions));
@@ -54,7 +62,7 @@ impl<'a> Display for ModuleDefinition<'a> {
     }
 }
 
-struct TableDefinitions(Vec<TableData>);
+struct TableDefinitions(Vec<TableData>, Vec<ForeignKeyConstraint>);
 
 impl Display for TableDefinitions {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
@@ -67,6 +75,14 @@ impl Display for TableDefinitions {
             }
             writeln!(f, "{}", TableDefinition(table))?;
         }
+
+        if !self.1.is_empty() {
+            write!(f, "\n")?;
+        }
+
+        for foreign_key in &self.1 {
+            writeln!(f, "{}", Joinable(foreign_key))?;
+        }
         Ok(())
     }
 }
@@ -118,6 +134,20 @@ impl<'a> Display for ColumnDefinitions<'a> {
     }
 }
 
+struct Joinable<'a>(&'a ForeignKeyConstraint);
+
+impl<'a> Display for Joinable<'a> {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(
+            f,
+            "joinable!({} -> {} ({}));",
+            self.0.child_table,
+            self.0.parent_table,
+            self.0.foreign_key,
+        )
+    }
+}
+
 /// Lifted directly from libcore/fmt/builders.rs
 struct PadAdapter<'a, 'b: 'a> {
     fmt: &'a mut Formatter<'b>,

diesel_cli/tests/print_schema.rs

@@ -5,7 +5,6 @@ fn run_infer_schema() {
     let p = project("print_schema").build();
     let db = database(&p.database_url());
 
-    // Make sure the project is setup
     p.command("setup").run();
 
     db.execute("CREATE TABLE users1 (id INTEGER PRIMARY KEY);");
@@ -85,7 +84,6 @@ fn run_infer_schema_whitelist() {
     let p = project("print_schema_whitelist").build();
     let db = database(&p.database_url());
 
-    // Make sure the project is setup
     p.command("setup").run();
 
     db.execute("CREATE TABLE users1 (id INTEGER PRIMARY KEY);");
@@ -137,7 +135,6 @@ fn run_infer_schema_blacklist() {
     let p = project("print_schema_blacklist").build();
     let db = database(&p.database_url());
 
-    // Make sure the project is setup
     p.command("setup").run();
 
     db.execute("CREATE TABLE users1 (id INTEGER PRIMARY KEY);");
@@ -189,7 +186,6 @@ fn run_infer_schema_order() {
     let p = project("print_schema_order").build();
     let db = database(&p.database_url());
 
-    // Make sure the project is setup
     p.command("setup").run();
 
     db.execute("CREATE TABLE def (id INTEGER PRIMARY KEY);");
@@ -299,7 +295,6 @@ fn run_infer_schema_compound_primary_key() {
     let p = project("print_schema_compound_primary_key").build();
     let db = database(&p.database_url());
 
-    // Make sure the project is setup
     p.command("setup").run();
 
     db.execute("CREATE TABLE asd (id INTEGER, qsd INTEGER, PRIMARY KEY (id, qsd));");
@@ -361,7 +356,6 @@ fn print_schema_specifying_schema_name() {
     let p = project("print_schema_specifying_schema_name").build();
     let db = database(&p.database_url());
 
-    // Make sure the project is setup
     p.command("setup").run();
 
     db.execute("CREATE SCHEMA custom_schema");
@@ -390,3 +384,79 @@ r"pub mod custom_schema {
 }
 ");
 }
+
+#[test]
+#[cfg(feature = "postgres")]
+fn print_schema_with_foreign_keys() {
+    let p = project("print_schema_with_foreign_keys").build();
+    let db = database(&p.database_url());
+
+    p.command("setup").run();
+
+    db.execute("CREATE TABLE users (id SERIAL PRIMARY KEY)");
+    db.execute("CREATE TABLE posts (id SERIAL PRIMARY KEY, user_id INTEGER NOT NULL REFERENCES users)");
+    db.execute("CREATE TABLE comments (id SERIAL PRIMARY KEY, post_id INTEGER NOT NULL REFERENCES posts)");
+
+    let result = p.command("print-schema").run();
+
+    assert!(result.is_success(), "Result was unsuccessful {:?}", result);
+
+    assert_eq!(result.stdout(),
+r"table! {
+    /// Representation of the `comments` table.
+    ///
+    /// (Automatically generated by Diesel.)
+    comments (id) {
+        /// The `id` column of the `comments` table.
+        ///
+        /// Its SQL type is `Int4`.
+        ///
+        /// (Automatically generated by Diesel.)
+        id -> Int4,
+        /// The `post_id` column of the `comments` table.
+        ///
+        /// Its SQL type is `Int4`.
+        ///
+        /// (Automatically generated by Diesel.)
+        post_id -> Int4,
+    }
+}
+
+table! {
+    /// Representation of the `posts` table.
+    ///
+    /// (Automatically generated by Diesel.)
+    posts (id) {
+        /// The `id` column of the `posts` table.
+        ///
+        /// Its SQL type is `Int4`.
+        ///
+        /// (Automatically generated by Diesel.)
+        id -> Int4,
+        /// The `user_id` column of the `posts` table.
+        ///
+        /// Its SQL type is `Int4`.
+        ///
+        /// (Automatically generated by Diesel.)
+        user_id -> Int4,
+    }
+}
+
+table! {
+    /// Representation of the `users` table.
+    ///
+    /// (Automatically generated by Diesel.)
+    users (id) {
+        /// The `id` column of the `users` table.
+        ///
+        /// Its SQL type is `Int4`.
+        ///
+        /// (Automatically generated by Diesel.)
+        id -> Int4,
+    }
+}
+
+joinable!(posts -> users (user_id));
+joinable!(comments -> posts (post_id));
+");
+}