dhall: Use --base-import-url flag for documentation (#128588)

This updates `pkgs.dhallPackages.buildDhallGitHubPackage` to use the
newly added `--base-import-url` `dhall-docs` flag.  This flag is used
by the generated documentation so that paths copied to the clipboard
represent complete URLs that can be imported instead of only the
relative path to the import.

2 files changed, 19 insertions, 4 deletions

diff --git a/pkgs/development/interpreters/dhall/build-dhall-github-package.nix b/pkgs/development/interpreters/dhall/build-dhall-github-package.nix
index 53adc5a9b1258..8f9e4d835511c 100644
--- a/pkgs/development/interpreters/dhall/build-dhall-github-package.nix
+++ b/pkgs/development/interpreters/dhall/build-dhall-github-package.nix
@@ -43,7 +43,7 @@ lib.makePackageOverridable
         "rev"
       ]);
 
-      prefix = lib.optionalString (directory != "") "${directory}/";
+      prefix = lib.optionalString (directory != "") "/${directory}";
 
     in
       buildDhallPackage
@@ -51,9 +51,12 @@ lib.makePackageOverridable
 
             name = versionedName;
 
-            code = "${src}/${prefix}${file}";
+            code = "${src}${prefix}/${file}";
           }
         // lib.optionalAttrs document
-          { documentationRoot = "${src}/${prefix}"; }
+          { documentationRoot = "${src}/${prefix}";
+
+            baseImportUrl = "https://raw.githubusercontent.com/${owner}/${repo}/${rev}${prefix}";
+          }
         )
   )
diff --git a/pkgs/development/interpreters/dhall/build-dhall-package.nix b/pkgs/development/interpreters/dhall/build-dhall-package.nix
index 9fc9a44121560..86797e9f136f6 100644
--- a/pkgs/development/interpreters/dhall/build-dhall-package.nix
+++ b/pkgs/development/interpreters/dhall/build-dhall-package.nix
@@ -37,6 +37,12 @@
   #
   # If `null`, then no documentation is generated.
 , documentationRoot ? null
+
+  # Base URL prepended to paths copied to the clipboard
+  #
+  # This is used in conjunction with `documentationRoot`, and is unused if
+  # `documentationRoot` is `null`.
+, baseImportUrl ? null
 }:
 
 let
@@ -85,6 +91,12 @@ in
     ${lib.optionalString (documentationRoot != null) ''
     mkdir -p $out/${dataDhall}
 
-    XDG_DATA_HOME=$out/${data} ${dhall-docs}/bin/dhall-docs --input '${documentationRoot}' --package-name '${name}' --output-link $out/docs
+    XDG_DATA_HOME=$out/${data} ${dhall-docs}/bin/dhall-docs --output-link $out/docs ${lib.cli.toGNUCommandLineShell { } {
+      base-import-url = baseImportUrl;
+
+      input = documentationRoot;
+
+      package-name = name;
+    }}
     ''}
   ''