Aport copySource.nix with descriptive error message

akirak · Jul 1, 2021 · 2f4ef77 · 2f4ef77
1 parent f4f69a7
commit 2f4ef77
Showing 1 changed file with 37 additions and 32 deletions.
diff --git a/nix/copySource.nix b/nix/copySource.nix
@@ -1,7 +1,7 @@
 # A helper for copying (actually linking) source files.
 #
 # This generates a shell script for the task.
-{ pkgs ? import <nixpkgs> {}
+{ pkgs ? import <nixpkgs> { }
 , src
 , recipeFile
 }:
@@ -23,35 +23,40 @@ let
       mainFileRegex = "(.*/)?" + recipeAttrs.pname + "\.el";
       isMainFile = file: match mainFileRegex file != null;
     in
-      rec {
-        inherit (recipeAttrs) pname;
-        packageFiles =
-          filter (file: match "(.*/)?flycheck_.+\.el" file == null)
-            (expandPackageFiles srcRoot recipeAttrs.files);
-        sourceFiles = filter isElisp packageFiles;
-        mainFile =
-          if length sourceFiles == 1
-          then head sourceFiles
-          else head (filter isMainFile sourceFiles);
-      };
+    rec {
+      inherit (recipeAttrs) pname;
+      packageFiles =
+        filter (file: match "(.*/)?flycheck_.+\.el" file == null)
+          (expandPackageFiles srcRoot recipeAttrs.files);
+      sourceFiles = filter isElisp packageFiles;
+      mainFile =
+        if length sourceFiles == 1
+        then head sourceFiles
+        else
+          let mainFiles = (filter isMainFile sourceFiles);
+          in
+          if mainFiles == [ ]
+          then abort "Main elisp file not found for recipe ${recipeFile}."
+          else head mainFiles;
+    };
 in
-  with package;
-  let
-    packageFilePaths = map (file: src + "/" + file) packageFiles;
-    baseNames = xs: concatStringsSep " " (map baseNameOf xs);
-  in
-    writeText "emacs-${package.pname}-link-source"
-      ''
-        cat > .elinter-env <<HERE
-        export PACKAGE_NAME=${pname}
-        export PACKAGE_FILES="${baseNames packageFiles}"
-        export PACKAGE_ELISP_FILES="${baseNames sourceFiles}"
-        export PACKAGE_MAIN_FILE=${baseNameOf mainFile}
-        HERE
-        for f in ${lib.escapeShellArgs packageFilePaths}; do
-          if ! ln -s $f; then
-            echo "This is possibly due to duplicate file specs in the recipe." >&2
-            exit 1
-          fi
-        done
-      ''
+with package;
+let
+  packageFilePaths = map (file: src + "/" + file) packageFiles;
+  baseNames = xs: concatStringsSep " " (map baseNameOf xs);
+in
+writeText "emacs-${package.pname}-link-source"
+  ''
+    cat > .elinter-env <<HERE
+    export PACKAGE_NAME=${pname}
+    export PACKAGE_FILES="${baseNames packageFiles}"
+    export PACKAGE_ELISP_FILES="${baseNames sourceFiles}"
+    export PACKAGE_MAIN_FILE=${baseNameOf mainFile}
+    HERE
+    for f in ${lib.escapeShellArgs packageFilePaths}; do
+      if ! ln -s $f; then
+        echo "This is possibly due to duplicate file specs in the recipe." >&2
+        exit 1
+      fi
+    done
+  ''