Add problem: ByNamePackagePrefixedWithNumber

src/problem/mod.rs

@@ -34,6 +34,8 @@ pub mod npv_161;
 pub mod npv_162;
 pub mod npv_163;
 
+pub mod npv_170;
+
 #[derive(Clone, Display, EnumFrom)]
 pub enum Problem {
     /// NPV-100: attribute is not defined but it should be defined automatically
@@ -123,6 +125,9 @@ pub enum Problem {
     NewTopLevelPackageShouldBeByNameWithCustomArgument(
         npv_163::NewTopLevelPackageShouldBeByNameWithCustomArgument,
     ),
+
+    /// NPV-170: by-name package cannot be number prefixed
+    ByNamePackegPrefixedWithNumber(npv_170::ByNamePackegPrefixedWithNumber),
 }
 
 fn indent_definition(column: usize, definition: &str) -> String {

src/problem/npv_170.rs

@@ -0,0 +1,25 @@
+use std::fmt;
+
+use derive_new::new;
+use relative_path::RelativePathBuf;
+
+#[derive(Clone, new)]
+pub struct ByNamePackegPrefixedWithNumber {
+    #[new(into)]
+    package_name: String,
+    #[new(into)]
+    relative_package_dir: RelativePathBuf,
+}
+
+impl fmt::Display for ByNamePackegPrefixedWithNumber {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let Self {
+            package_name,
+            relative_package_dir,
+        } = self;
+        write!(
+            f,
+            r#"- {relative_package_dir}: Attribute `{package_name}` should not be number-prefixed. It is suggestet to `"`-wrap this name"#
+        )
+    }
+}

src/structure.rs

@@ -7,7 +7,9 @@ use lazy_static::lazy_static;
 use regex::Regex;
 use relative_path::RelativePathBuf;
 
-use crate::problem::{npv_109, npv_110, npv_111, npv_140, npv_141, npv_142, npv_143, npv_144};
+use crate::problem::{
+    npv_109, npv_110, npv_111, npv_140, npv_141, npv_142, npv_143, npv_144, npv_170,
+};
 use crate::references;
 use crate::validation::{self, ResultIteratorExt, Validation::Success};
 use crate::NixFileStore;
@@ -16,8 +18,9 @@ pub const BASE_SUBPATH: &str = "pkgs/by-name";
 pub const PACKAGE_NIX_FILENAME: &str = "package.nix";
 
 lazy_static! {
-    static ref SHARD_NAME_REGEX: Regex = Regex::new(r"^[a-z0-9_-]{1,2}$").unwrap();
-    static ref PACKAGE_NAME_REGEX: Regex = Regex::new(r"^[a-zA-Z0-9_-]+$").unwrap();
+    static ref SHARD_NAME_REGEX: Regex = Regex::new(r"^((_[0-9])|([a-z][a-z0-9_-]?))$").unwrap();
+    static ref PACKAGE_NAME_REGEX: Regex =
+        Regex::new(r"^((_[0-9])|[a-zA-Z])[a-zA-Z0-9_-]*$").unwrap();
 }
 
 /// Deterministic file listing so that tests are reproducible.
@@ -137,11 +140,23 @@ fn check_package(
     } else {
         let package_name_valid = PACKAGE_NAME_REGEX.is_match(&package_name);
         let result = if !package_name_valid {
-            npv_141::InvalidPackageDirectoryName::new(
-                package_name.clone(),
-                relative_package_dir.clone(),
-            )
-            .into()
+            if package_name
+                .chars()
+                .next()
+                .is_some_and(|c| c.is_ascii_digit())
+            {
+                npv_170::ByNamePackegPrefixedWithNumber::new(
+                    package_name.clone(),
+                    relative_package_dir.clone(),
+                )
+                .into()
+            } else {
+                npv_141::InvalidPackageDirectoryName::new(
+                    package_name.clone(),
+                    relative_package_dir.clone(),
+                )
+                .into()
+            }
         } else {
             Success(())
         };

tests/by-name-numprefix/default.nix

@@ -0,0 +1 @@
+import <test-nixpkgs> { root = ./.; }

tests/by-name-numprefix/expected

@@ -0,0 +1,2 @@
+- pkgs/by-name/_1/10foo: Attribute `10foo` should not be number-prefixed. It is suggestet to `"`-wrap this name
+This PR introduces the problems listed above. Please fix them before merging, otherwise the base branch would break.

tests/by-name-numprefix/pkgs/by-name/_1/10foo/package.nix

@@ -0,0 +1,4 @@
+{ someDrv }:
+SomeDrv
+# If we caused an actual Nix failure
+# builtins.trace "This should be on stderr!" throw "This is an error!"