fix(add): error when config file contains importMap field (#25115)

The "imports" field has higher precedence than "importMap", so we should
error when `deno add` goes to add an `"imports"` field.

Closes https://github.com/denoland/deno/issues/24264
Closes https://github.com/denoland/deno/pull/24478

1 files changed, 11 insertions, 0 deletions

diff --git a/cli/tools/registry/pm.rs b/cli/tools/registry/pm.rs
index 52f3310ba..3cdef071f 100644
--- a/cli/tools/registry/pm.rs
+++ b/cli/tools/registry/pm.rs
@@ -289,6 +289,17 @@ pub async fn add(
     _ => bail!("Failed updating config file due to no object."),
   };
 
+  if obj.get_string("importMap").is_some() {
+    bail!(
+      concat!(
+        "`deno add` is not supported when configuration file contains an \"importMap\" field. ",
+        "Inline the import map into the Deno configuration file.\n",
+        "    at {}",
+      ),
+      config_specifier
+    );
+  }
+
   let mut existing_imports = config_file.existing_imports()?;
 
   let is_npm = config_file.is_npm();