Added warnings and updated docs for --no-hash-check flag

README.md

@@ -149,6 +149,10 @@ For reference, here is the default configuration file:
 A hash of the migration file is saved to the database when a migration is applied. This way, we can ensure that migrations are not modified after being applied.
 If a migration has been modified, you will get an error as it probably means that you should reset your database to update a migration.
 
+During development, you may want to edit your migrations after they have been applied to your database. In that case, you can use the `--no-hash-check` flag to
+bypass hash checking when you want to apply or rollback migrations. It isn't recommended to use this flag in production, because then your migrations scripts
+don't match what is in your database !
+
 > This feature was introduced in version 3 of cigogne.
 > Note that it requires Gleam >=1.9.0.
 > If you use earlier versions of the library, you can use the to_v3 script to have them filled automatically.

src/cigogne.gleam

@@ -145,6 +145,8 @@ pub fn main() {
 pub fn create_engine(
   config: config.Config,
 ) -> Result(MigrationEngine, CigogneError) {
+  warn_no_hash_check(config)
+
   use #(db_data, applied) <- result.try(init_db_and_get_applied(config))
   use files <- result.try(read_migrations(config))
   use applied <- result.try(
@@ -160,6 +162,16 @@ pub fn create_engine(
   Ok(MigrationEngine(db_data:, applied:, unapplied:, files:, config:))
 }
 
+fn warn_no_hash_check(config: config.Config) -> Nil {
+  case config.migrations.no_hash_check {
+    option.Some(True) ->
+      io.println(
+        "Warning: no_hash_check is enabled ! Do not use it in production environments as it can lead to inconsistencies between your migration files and the database.",
+      )
+    _ -> Nil
+  }
+}
+
 fn init_db_and_get_applied(
   config: config.Config,
 ) -> Result(#(database.DatabaseData, List(migration.Migration)), CigogneError) {

src/cigogne/internal/cli.gleam

@@ -286,7 +286,7 @@ fn migrations_config_decoder(
     "no-hash-check",
     [],
     "",
-    "/!\\ Warning: not recommended /!\\ Disable hash checks on engine creation",
+    "/!\\ Warning: not recommended in production /!\\ Disable hash checks on engine creation. Can be useful during development.",
     cli_lib.bool,
   )
 

src/cigogne/migration.gleam

@@ -1,6 +1,7 @@
 import cigogne/internal/utils
 import gleam/bool
 import gleam/int
+import gleam/io
 import gleam/list
 import gleam/order
 import gleam/result
@@ -170,7 +171,14 @@ pub fn match_migrations(
     case match_res {
       Ok(match) -> {
         case no_hash_check || migration.sha256 == match.sha256 {
-          True -> Ok(match)
+          True -> {
+            io.println(
+              "Warning: Hash of file "
+              <> to_fullname(migration)
+              <> " has changed, but hash check is disabled.",
+            )
+            Ok(match)
+          }
           False -> Error(FileHashChanged(migration |> to_fullname()))
         }
       }