Clean the code for the revert feature

Author: theredfish

diesel_cli/src/cli.rs

@@ -236,15 +236,13 @@ fn migration_dir_arg<'a, 'b>() -> Arg<'a, 'b> {
 }
 
 fn migration_revert_number_validator(val: String) -> Result<(), String> {
-
     if val == "all" {
         return Ok(());
     }
 
-    let number = match val.parse::<i64>() {
-        Ok(number) => number,
-        Err(_) => return Err("Cannot parse <REVERT_NUMBER>. The input must be an integer or 'all'.".to_string())
-    };
+    let number = val.parse::<i64>().map_err(|_| {
+        "Cannot parse <REVERT_NUMBER>. The input must be an integer or 'all'.".to_string()
+    })?;
 
     if number < 1 {
         return Err("<REVERT_NUMBER> must be at least equal to 1.".to_string());

diesel_cli/src/main.rs

@@ -75,22 +75,24 @@ fn run_migration_command(matches: &ArgMatches) -> Result<(), Box<dyn Error>> {
             let database_url = database::database_url(matches);
             let dir = migrations_dir(matches).unwrap_or_else(handle_error);
 
-            match args.value_of("REVERT_NUMBER") {
-                Some("all") => {
+            // We can unwrap since the argument is validated from the cli module.
+            // The value is required and is a number greater than 0 or "all".
+            let number = args.value_of("REVERT_NUMBER").unwrap();
+
+            // Test if we have an integer or "all"
+            match number.parse::<i64>() {
+                Ok(number) => {
                     call_with_conn!(
                         database_url,
-                        migrations::revert_all_migrations_in_directory(&dir)
+                        migrations::revert_latest_migrations_in_directory(&dir, number)
                     )?;
                 }
-                Some(n) => {
-                    let x = n.parse::<i64>().unwrap_or_else(handle_error);
-
+                _ => {
                     call_with_conn!(
                         database_url,
-                        migrations::revert_latest_migrations_in_directory(&dir, x)
+                        migrations::revert_all_migrations_in_directory(&dir)
                     )?;
                 }
-                None => unreachable!("REVERT_NUMBER has a default value"),
             }
 
             regenerate_schema_if_file_specified(matches)?;

diesel_cli/tests/migration_revert.rs

@@ -2,7 +2,9 @@ use crate::support::{database, project};
 
 #[test]
 fn migration_revert_runs_the_last_migration_down() {
-    let p = project("migration_revert_runs_the_last_migration_down").folder("migrations").build();
+    let p = project("migration_revert_runs_the_last_migration_down")
+        .folder("migrations")
+        .build();
     let db = database(&p.database_url());
 
     p.create_migration(
@@ -131,7 +133,9 @@ fn migration_revert_respects_migration_dir_from_diesel_toml() {
 
 #[test]
 fn migration_revert_runs_the_last_two_migration_down() {
-    let p = project("migration_revert_runs_the_last_two_migration_down").folder("migrations").build();
+    let p = project("migration_revert_runs_the_last_two_migration_down")
+        .folder("migrations")
+        .build();
     let db = database(&p.database_url());
 
     p.create_migration(
@@ -182,7 +186,9 @@ fn migration_revert_runs_the_last_two_migration_down() {
 
 #[test]
 fn migration_revert_all_runs_the_migrations_down() {
-    let p = project("migration_revert_all_runs_the_migrations_down").folder("migrations").build();
+    let p = project("migration_revert_all_runs_the_migrations_down")
+        .folder("migrations")
+        .build();
     let db = database(&p.database_url());
 
     p.create_migration(
@@ -239,7 +245,9 @@ fn migration_revert_all_runs_the_migrations_down() {
 
 #[test]
 fn migration_revert_with_zero_should_throw_an_error() {
-    let p = project("migration_revert_with_zero_should_throw_an_error").folder("migrations").build();
+    let p = project("migration_revert_with_zero_should_throw_an_error")
+        .folder("migrations")
+        .build();
 
     // Make sure the project is setup
     p.command("setup").run();
@@ -263,7 +271,9 @@ fn migration_revert_with_zero_should_throw_an_error() {
 
 #[test]
 fn migration_revert_with_an_invalid_input_should_throw_an_error() {
-    let p = project("migration_revert_with_an_invalid_input_should_throw_an_error").folder("migrations").build();
+    let p = project("migration_revert_with_an_invalid_input_should_throw_an_error")
+        .folder("migrations")
+        .build();
 
     // Make sure the project is setup
     p.command("setup").run();