From 0ce6504c6c0679f45505273af59f00048a405d1d Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <slyich@gmail.com>
Date: Thu, 25 Dec 2025 21:33:39 +0000
Subject: [PATCH] pkgsLLVM.git-doc: improve eval error
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Before the change `pkgsLLVM.git-doc` evaluated to uncatchable error:

    $ nix build --no-link -f. pkgsLLVM.git-doc
    error:
       … while evaluating a branch condition
         at pkgs/top-level/splice.nix:59:11:
           58|           # on to splice them together.
           59|           if lib.isDerivation defaultValue then
             |           ^
           60|             augmentedValue

       … while evaluating the attribute 'git-doc'
         at pkgs/top-level/all-packages.nix:1159:3:
         1158|
         1159|   git-doc = lib.addMetaAttrs {
             |   ^
         1160|     description = "Additional documentation for Git";

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: attribute 'doc' missing
       at pkgs/top-level/all-packages.nix:1165:5:
         1164|     '';
         1165|   } gitFull.doc;
             |     ^
         1166|
       Did you mean src?

After the change it's more typical `throw` error:

    $ nix build --no-link -f. pkgsLLVM.git-doc
     error:
       … while evaluating a branch condition
         at pkgs/top-level/splice.nix:59:11:
           58|           # on to splice them together.
           59|           if lib.isDerivation defaultValue then
             |           ^
           60|             augmentedValue

       … while evaluating the attribute 'git-doc'
         at pkgs/top-level/all-packages.nix:1159:3:
         1158|
         1159|   git-doc =
             |   ^
         1160|     # doc attribnute is not present at least for pkgsLLVM

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: 'git-doc' can't be evaluated as 'gitFull' does no expose 'doc' attribute

Co-authored-by: Colin <accounts.github@uninsane.org>
Co-authored-by: Doron Behar <doron.behar@gmail.com>
---
 pkgs/top-level/all-packages.nix | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 6d24e7993433..9f1833803585 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -1156,13 +1156,18 @@ with pkgs;
   # Git with SVN support, but without GUI.
   gitSVN = lowPrio (git.override { svnSupport = true; });
 
-  git-doc = lib.addMetaAttrs {
-    description = "Additional documentation for Git";
-    longDescription = ''
-      This package contains additional documentation (HTML and text files) that
-      is referenced in the man pages of Git.
-    '';
-  } gitFull.doc;
+  git-doc =
+    # doc attribute is not present at least for pkgsLLVM
+    if (gitFull ? doc) then
+      lib.addMetaAttrs {
+        description = "Additional documentation for Git";
+        longDescription = ''
+          This package contains additional documentation (HTML and text files) that
+          is referenced in the man pages of Git.
+        '';
+      } gitFull.doc
+    else
+      throw "'git-doc' can't be evaluated as 'gitFull' does not expose 'doc' attribute";
 
   gitMinimal = git.override {
     withManual = false;