From 82b638c18d442cb50b7f24d3e5fad14e63082bc8 Mon Sep 17 00:00:00 2001
From: John Freeman <jfreeman08@gmail.com>
Date: Tue, 5 Nov 2024 11:41:45 -0600
Subject: [PATCH 1/5] Fix internal Conan component requirements

---
 cmake/cupcake_add_library.cmake            |   4 +-
 cmake/cupcake_project.cmake                |   1 +
 cmake/data/install_cpp_info.cmake          |   1 +
 cmake/data/project_cpp_info/CMakeLists.txt | 114 +++++++++++++++------
 4 files changed, 84 insertions(+), 36 deletions(-)

diff --git a/cmake/cupcake_add_library.cmake b/cmake/cupcake_add_library.cmake
index a0c0763..8309287 100644
--- a/cmake/cupcake_add_library.cmake
+++ b/cmake/cupcake_add_library.cmake
@@ -36,9 +36,6 @@ function(cupcake_add_library name)
   if(name STREQUAL PROJECT_NAME)
     add_library(${PROJECT_NAME}.library ALIAS ${target})
   endif()
-  set_target_properties(${target} PROPERTIES
-    EXPORT_NAME libraries::${name}
-  )
 
   target_link_libraries(${PROJECT_NAME}.libraries INTERFACE ${target})
 
@@ -112,6 +109,7 @@ function(cupcake_add_library name)
   endif()
 
   if(NOT arg_PRIVATE)
+    set_target_properties(${target} PROPERTIES EXPORT_NAME libraries::${name})
     set(alias ${PROJECT_NAME}::libraries::${name})
     add_library(${alias} ALIAS ${target})
     add_library(${PROJECT_NAME}::l::${name} ALIAS ${target})
diff --git a/cmake/cupcake_project.cmake b/cmake/cupcake_project.cmake
index 502e768..8df2d2a 100644
--- a/cmake/cupcake_project.cmake
+++ b/cmake/cupcake_project.cmake
@@ -101,6 +101,7 @@ macro(cupcake_project)
 
   set(target ${PROJECT_NAME}.imports.main)
   add_library(${target} INTERFACE)
+  set_target_properties(${target} PROPERTIES EXPORT_NAME imports::main)
   install(TARGETS ${target} EXPORT ${PROJECT_EXPORT_SET})
   add_library(${PROJECT_NAME}::imports::main ALIAS ${target})
 
diff --git a/cmake/data/install_cpp_info.cmake b/cmake/data/install_cpp_info.cmake
index 1eaeaaf..a43fb05 100644
--- a/cmake/data/install_cpp_info.cmake
+++ b/cmake/data/install_cpp_info.cmake
@@ -48,5 +48,6 @@ execute_process(
     "-DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}"
     "${CUPCAKE_MODULE_DIR}/data/project_cpp_info"
   WORKING_DIRECTORY "${tmp_dir}"
+  COMMAND_ERROR_IS_FATAL ANY
 )
 file(REMOVE_RECURSE "${tmp_dir}")
diff --git a/cmake/data/project_cpp_info/CMakeLists.txt b/cmake/data/project_cpp_info/CMakeLists.txt
index ed9bb15..6cc1687 100644
--- a/cmake/data/project_cpp_info/CMakeLists.txt
+++ b/cmake/data/project_cpp_info/CMakeLists.txt
@@ -23,7 +23,13 @@ string(APPEND cpp_info
   "self.set_property('cmake_find_mode', 'config')\n"
 )
 
-set(target_pattern "^([^:]+)::(.+)$")
+unset(buffer.log)
+macro(log level text)
+  message(${level} "${text}")
+  string(APPEND buffer.log "# [${level}] ${text}\n")
+endmacro()
+
+set(pattern_scope "^([^:]+)::(.+)$")
 
 # For each library target, add Python statements to the script text
 # to declare these properties on a component named after the target:
@@ -36,9 +42,23 @@ set(target_pattern "^([^:]+)::(.+)$")
 # - sharedlinkflags: list of linker flags for shared libraries
 # - libs: singleton list of installed library name to be searched by linker
 # - libdirs: singleton list of directory, relative to the install prefix, where library is installed
-foreach(target ${${PACKAGE_NAME}_LIBRARIES})
+
+# `libraries` is the set of libraries that
+# have been or will be added as Conan components.
+set(libraries ${${PACKAGE_NAME}_LIBRARIES})
+# `targets` is the subset of `libraries` that
+# have not yet been added as Conan components.
+set(targets ${libraries})
+# On each iteration, we will remove one target from `targets`,
+# and add zero or more targets to `targets` and `libraries`
+# if they do not already appear in `libraries`.
+while(targets)
+  list(POP_FRONT targets target)
+
+  # log(STATUS "target = ${target}")
+
   # Peel off the namespace to get the unqualified CMake target name.
-  string(REGEX MATCH "${target_pattern}" match ${target})
+  string(REGEX MATCH "${pattern_scope}" match ${target})
   if(NOT CMAKE_MATCH_1 STREQUAL PACKAGE_NAME)
     message(FATAL_ERROR "foreign target: '${target}'")
   endif()
@@ -46,21 +66,22 @@ foreach(target ${${PACKAGE_NAME}_LIBRARIES})
   # Target name unqualified by package name.
   set(tname ${CMAKE_MATCH_2})
 
-  string(REGEX MATCH "${target_pattern}" match ${tname})
-  if(NOT CMAKE_MATCH_1 STREQUAL "libraries")
+  string(REGEX MATCH "${pattern_scope}" match ${tname})
+  set(type ${CMAKE_MATCH_1})
+  if(NOT (type STREQUAL "libraries" OR type STREQUAL "imports"))
     message(FATAL_ERROR "not a library: '${target}'")
   endif()
 
   # Library name.
   set(name ${CMAKE_MATCH_2})
   # Component name cannot contain double colon (::).
-  set(cname libraries.${name})
-  set(components "${components}'${cname}',")
+  set(cname ${type}.${name})
+  string(APPEND components "'${cname}',")
 
-  # "${cname}" == "libraries.${name}"
-  set(aliases "'${PACKAGE_NAME}::l::${name}'")
-  if(name STREQUAL PACKAGE_NAME)
-    set(aliases "${aliases},'${PACKAGE_NAME}::library'")
+  string(SUBSTRING ${type} 0 1 shorthand)
+  set(aliases "'${PACKAGE_NAME}::${shorthand}::${name}'")
+  if(type STREQUAL "libraries" AND name STREQUAL PACKAGE_NAME)
+    string(APPEND aliases ",'${PACKAGE_NAME}::library'")
   endif()
 
   string(APPEND cpp_info
@@ -73,28 +94,54 @@ foreach(target ${${PACKAGE_NAME}_LIBRARIES})
   )
 
   get_target_property(links ${target} INTERFACE_LINK_LIBRARIES)
-  if(links)
-    unset(requires)
-    foreach(link ${links})
-      if(NOT TARGET ${link})
-        message(STATUS "ignoring non-target link '${link}' of target '${target}'")
-        continue()
+  unset(requires)
+  while(links)
+    list(POP_FRONT links link)
+    # Each link is one of:
+    # - An internal target.
+    # - An external target.
+    # - A non-target, most likely a library name or absolute path.
+    if(NOT TARGET ${link})
+      log(ERROR "ignoring non-target link '${link}' of target '${target}'")
+      continue()
+    endif()
+    # Unalias once we've confirmed that it is a target.
+    get_target_property(linked ${link} ALIASED_TARGET)
+    if(linked)
+      set(link ${linked})
+    endif()
+    # log(STATUS "link = ${link}")
+    # An internal target starts with "${PACKAGE_NAME}::".
+    # Everything else is an external target.
+    # We cannot distinguish internal vs external libraries by whether they are
+    # imported. It does not work when "importing" external libraries with
+    # `add_subdirectory`. The subdirectory's targets would not be imported,
+    # but would not be internal either, unless we install them.
+    string(REGEX MATCH "${pattern_scope}" match ${link})
+    if(CMAKE_MATCH_1 STREQUAL PACKAGE_NAME)
+      # Internal target.
+      # Add it to `targets` (and `libraries`) if not yet in `libraries`.
+      list(FIND libraries "${link}" index)
+      if(index LESS 0)
+        list(APPEND libraries "${link}")
+        list(APPEND targets "${link}")
       endif()
-      # TODO: We could try to distinguish internal vs external libraries by
-      # whether they are imported, but that would not work when taking
-      # dependencies by add_subdirectory unless we install their libraries as
-      # internal libraries.
-      string(REGEX MATCH "${target_pattern}" match ${link})
-      if(CMAKE_MATCH_1 STREQUAL PACKAGE_NAME)
-        set(lname ${CMAKE_MATCH_2})
-      else()
-        get_target_property(lname ${link} ALIASED_TARGET)
-        if(NOT lname)
-          set(lname ${link})
-        endif()
+      # Translate to Conan component name.
+      if(NOT CMAKE_MATCH_2 MATCHES "${pattern_scope}")
+        message(FATAL_ERROR "illegal internal target name: ${link}")
       endif()
-      string(APPEND requires "'${lname}',")
-    endforeach()
+      set(lname ${CMAKE_MATCH_1}.${CMAKE_MATCH_2})
+    else()
+      # External target.
+      # TODO: Find Conan component name in variable map `CUPCAKE_CONAN_COMPONENT`.
+      # TODO: Pre-populate `CUPCAKE_CONAN_COMPONENT` from `cupcake.json`.
+      set(lname ${link})
+    endif()
+    list(APPEND requires "'${lname}'")
+  endwhile()
+  if(requires)
+    list(REMOVE_DUPLICATES requires)
+    list(JOIN requires "," requires)
     string(APPEND cpp_info
       "self.components['${cname}'].requires = [${requires}]\n"
     )
@@ -163,11 +210,12 @@ foreach(target ${${PACKAGE_NAME}_LIBRARIES})
       )
     endif()
   endif()
-endforeach()
+endwhile()
 
 string(APPEND cpp_info
-  "self.components['libraries'].set_property('cmake_target_name', 'zero::libraries')\n"
+  "self.components['libraries'].set_property('cmake_target_name', '${PACKAGE_NAME}::libraries')\n"
   "self.components['libraries'].requires = [${components}]\n"
+  "${buffer.log}"
 )
 
 # There is no way to model executables in `cpp_info`.

From 8ce3a1acaa76bf8d297662834058bfadc2e9c721 Mon Sep 17 00:00:00 2001
From: John Freeman <jfreeman08@gmail.com>
Date: Wed, 6 Nov 2024 10:27:53 -0600
Subject: [PATCH 2/5] Slim down with cupcake_json_get_list

---
 cmake/cupcake_add_executables.cmake | 65 ++++++++++++-----------------
 cmake/cupcake_add_libraries.cmake   | 65 ++++++++++++-----------------
 cmake/cupcake_add_tests.cmake       | 49 +++++++++-------------
 cmake/cupcake_find_packages.cmake   | 38 +++++++----------
 cmake/cupcake_json.cmake            | 14 +++++--
 cmake/cupcake_link_libraries.cmake  | 36 +++++++---------
 6 files changed, 112 insertions(+), 155 deletions(-)

diff --git a/cmake/cupcake_add_executables.cmake b/cmake/cupcake_add_executables.cmake
index 2abcbde..cc34897 100644
--- a/cmake/cupcake_add_executables.cmake
+++ b/cmake/cupcake_add_executables.cmake
@@ -7,49 +7,36 @@ include(cupcake_json)
 function(cupcake_add_executables)
   cupcake_assert_special()
 
-  # executables = metadata.get('executables', []):
-  # executables :: [{ name :: string, links? :: array }]
-  cupcake_json_get(executables ARRAY "[]" "${PROJECT_JSON}" executables)
-  # for executable in executables:
-  string(JSON count LENGTH "${executables}")
-  if(count GREATER 0)
-    math(EXPR stop "${count} - 1")
-    foreach(i RANGE ${stop})
-      # executable :: { name :: string, private? :: boolean, links :: array }
-      string(JSON executable GET "${executables}" ${i})
+  # executables = metadata.get('executables', [])
+  cupcake_json_get_list(executables "${PROJECT_JSON}" executables)
+  foreach(executable IN LISTS executables)
+    # executable :: { name :: string, private? :: boolean, links :: array }
 
-      # If ${name} is a JSON string, it is unquoted here.
-      string(JSON name GET "${executable}" name)
-      cupcake_json_get(private BOOLEAN "false" "${executable}" private)
-      if(private)
-        set(private PRIVATE)
-      else()
-        set(private)
-      endif()
-      cupcake_add_executable(${name} ${private} "${ARGN}")
+    # If ${name} is a JSON string, it is unquoted here.
+    string(JSON name GET "${executable}" name)
+    cupcake_json_get(private BOOLEAN "false" "${executable}" private)
+    if(private)
+      set(private PRIVATE)
+    else()
+      set(private)
+    endif()
+    cupcake_add_executable(${name} ${private} "${ARGN}")
 
-      cupcake_json_get(links ARRAY "[]" "${executable}" links)
-      # links :: [
+    cupcake_json_get_list(links "${executable}" links)
+    foreach(link IN LISTS links)
+      # link ::
       #   | string
       #   | { target :: string, scope? :: PUBLIC | PRIVATE | INTERFACE }
-      # ]
-      string(JSON count LENGTH "${links}")
-      if(count GREATER 0)
-        math(EXPR stop "${count} - 1")
-        foreach(j RANGE ${stop})
-          string(JSON link GET "${links}" ${j})
-          string(JSON type TYPE "${links}" ${j})
-          if(type STREQUAL STRING)
-            set(target "${link}")
-            set(scope "PRIVATE")
-          else()
-            string(JSON target GET "${link}" target)
-            cupcake_json_get(scope STRING "PRIVATE" "${link}" scope)
-          endif()
-          cmake_language(EVAL CODE "set(target ${target})")
-          target_link_libraries(${this} ${scope} ${target})
-        endforeach()
+      string(JSON type TYPE "${link}")
+      if(type STREQUAL STRING)
+        set(target "${link}")
+        set(scope "PRIVATE")
+      else()
+        string(JSON target GET "${link}" target)
+        cupcake_json_get(scope STRING "PRIVATE" "${link}" scope)
       endif()
+      cmake_language(EVAL CODE "set(target ${target})")
+      target_link_libraries(${this} ${scope} ${target})
     endforeach()
-  endif()
+  endforeach()
 endfunction()
diff --git a/cmake/cupcake_add_libraries.cmake b/cmake/cupcake_add_libraries.cmake
index d2659f9..8a513b5 100644
--- a/cmake/cupcake_add_libraries.cmake
+++ b/cmake/cupcake_add_libraries.cmake
@@ -7,49 +7,36 @@ include(cupcake_json)
 function(cupcake_add_libraries)
   cupcake_assert_special()
 
-  # libraries = metadata.get('libraries', []):
-  # libraries :: [{ name :: string, links? :: array }]
-  cupcake_json_get(libraries ARRAY "[]" "${PROJECT_JSON}" libraries)
-  # for library in libraries:
-  string(JSON count LENGTH "${libraries}")
-  if(count GREATER 0)
-    math(EXPR stop "${count} - 1")
-    foreach(i RANGE ${stop})
-      # library :: { name :: string, private? :: boolean, links :: array }
-      string(JSON library GET "${libraries}" ${i})
+  # libraries = metadata.get('libraries', [])
+  cupcake_json_get_list(libraries "${PROJECT_JSON}" libraries)
+  foreach(library IN LISTS libraries)
+    # library :: { name :: string, private? :: boolean, links :: array }
 
-      # If ${name} is a JSON string, it is unquoted here.
-      string(JSON name GET "${library}" name)
-      cupcake_json_get(private BOOLEAN "false" "${library}" private)
-      if(private)
-        set(private PRIVATE)
-      else()
-        set(private)
-      endif()
-      cupcake_add_library(${name} ${private} "${ARGN}")
+    # If ${name} is a JSON string, it is unquoted here.
+    string(JSON name GET "${library}" name)
+    cupcake_json_get(private BOOLEAN "false" "${library}" private)
+    if(private)
+      set(private PRIVATE)
+    else()
+      set(private)
+    endif()
+    cupcake_add_library(${name} ${private} "${ARGN}")
 
-      cupcake_json_get(links ARRAY "[]" "${library}" links)
-      # links :: [
+    cupcake_json_get_list(links "${library}" links)
+    foreach(link IN LISTS links)
+      # link ::
       #   | string
       #   | { target :: string, scope? :: PUBLIC | PRIVATE | INTERFACE }
-      # ]
-      string(JSON count LENGTH "${links}")
-      if(count GREATER 0)
-        math(EXPR stop "${count} - 1")
-        foreach(j RANGE ${stop})
-          string(JSON link GET "${links}" ${j})
-          string(JSON type TYPE "${links}" ${j})
-          if(type STREQUAL STRING)
-            set(target "${link}")
-            set(scope "PUBLIC")
-          else()
-            string(JSON target GET "${link}" target)
-            cupcake_json_get(scope STRING "PUBLIC" "${link}" scope)
-          endif()
-          cmake_language(EVAL CODE "set(target ${target})")
-          target_link_libraries(${this} ${scope} ${target})
-        endforeach()
+      string(JSON type TYPE "${link}")
+      if(type STREQUAL STRING)
+        set(target "${link}")
+        set(scope "PUBLIC")
+      else()
+        string(JSON target GET "${link}" target)
+        cupcake_json_get(scope STRING "PUBLIC" "${link}" scope)
       endif()
+      cmake_language(EVAL CODE "set(target ${target})")
+      target_link_libraries(${this} ${scope} ${target})
     endforeach()
-  endif()
+  endforeach()
 endfunction()
diff --git a/cmake/cupcake_add_tests.cmake b/cmake/cupcake_add_tests.cmake
index 02710a7..1d3532b 100644
--- a/cmake/cupcake_add_tests.cmake
+++ b/cmake/cupcake_add_tests.cmake
@@ -6,40 +6,29 @@ include(cupcake_json)
 
 function(cupcake_add_tests)
   cupcake_assert_special()
-  cupcake_json_get(tests ARRAY "[]" "${PROJECT_JSON}" tests)
-  # tests :: [{ name :: string, links? :: array }]
-  string(JSON count LENGTH "${tests}")
-  if(count GREATER 0)
-    math(EXPR stop "${count} - 1")
-    foreach(i RANGE ${stop})
-      string(JSON test GET "${tests}" ${i})
+  cupcake_json_get_list(tests "${PROJECT_JSON}" tests)
+  foreach(test IN LISTS tests)
+    # test :: { name :: string, links? :: array }
 
-      string(JSON name GET "${test}" name)
-      # If ${name} is a JSON string, it is unquoted here.
-      cupcake_add_test(${name} "${ARGN}")
+    string(JSON name GET "${test}" name)
+    # If ${name} is a JSON string, it is unquoted here.
+    cupcake_add_test(${name} "${ARGN}")
 
-      cupcake_json_get(links ARRAY "[]" "${test}" links)
-      # links :: [
+    cupcake_json_get_list(links "${test}" links)
+    foreach(link IN LISTS links)
+      # link ::
       #   | string
       #   | { target :: string, scope? :: PUBLIC | PRIVATE | INTERFACE }
-      # ]
-      string(JSON count LENGTH "${links}")
-      if(count GREATER 0)
-        math(EXPR stop "${count} - 1")
-        foreach(j RANGE ${stop})
-          string(JSON link GET "${links}" ${j})
-          string(JSON type TYPE "${links}" ${j})
-          if(type STREQUAL STRING)
-            set(target "${link}")
-            set(scope "PRIVATE")
-          else()
-            string(JSON target GET "${link}" target)
-            cupcake_json_get(scope STRING "PRIVATE" "${link}" scope)
-          endif()
-          cmake_language(EVAL CODE "set(target ${target})")
-          target_link_libraries(${this} ${scope} ${target})
-        endforeach()
+      string(JSON type TYPE "${link}")
+      if(type STREQUAL STRING)
+        set(target "${link}")
+        set(scope "PRIVATE")
+      else()
+        string(JSON target GET "${link}" target)
+        cupcake_json_get(scope STRING "PRIVATE" "${link}" scope)
       endif()
+      cmake_language(EVAL CODE "set(target ${target})")
+      target_link_libraries(${this} ${scope} ${target})
     endforeach()
-  endif()
+  endforeach()
 endfunction()
diff --git a/cmake/cupcake_find_packages.cmake b/cmake/cupcake_find_packages.cmake
index 6286e69..45f89d3 100644
--- a/cmake/cupcake_find_packages.cmake
+++ b/cmake/cupcake_find_packages.cmake
@@ -8,26 +8,20 @@ include(cupcake_json)
 # TODO: Default `group` to `main`.
 function(cupcake_find_packages group)
   cupcake_assert_special()
-  cupcake_json_get(imports ARRAY "[]" "${PROJECT_JSON}" imports)
-  # imports :: [{ file :: string?, targets :: [string], groups :: [string] }]
-  string(JSON count LENGTH "${imports}")
-  if(count GREATER 0)
-    math(EXPR stop "${count} - 1")
-    foreach(i RANGE ${stop})
-      string(JSON import GET "${imports}" ${i})
-      # Select only imports whose `groups` (default: `["main"]`)
-      # contain `group`.
-      cupcake_json_get(groups ARRAY "[\"main\"]" "${import}" groups)
-      cupcake_json_to_list(groups "${groups}")
-      list(FIND groups "${group}" j)
-      if(j LESS 0)
-        continue()
-      endif()
-      string(JSON file GET "${import}" file)
-      if(NOT file)
-        string(JSON file GET "${import}" name)
-      endif()
-      cupcake_find_package("${file}" "${ARGN}")
-    endforeach()
-  endif()
+  cupcake_json_get_list(imports "${PROJECT_JSON}" imports)
+  foreach(import IN LISTS imports)
+    # import :: { file :: string?, targets :: [string], groups :: [string] }
+    # Select only imports whose `groups` (default: `["main"]`) contain `group`.
+    cupcake_json_get(groups ARRAY "[\"main\"]" "${import}" groups)
+    cupcake_json_to_list(groups "${groups}")
+    list(FIND groups "${group}" i)
+    if(i LESS 0)
+      continue()
+    endif()
+    string(JSON file GET "${import}" file)
+    if(NOT file)
+      string(JSON file GET "${import}" name)
+    endif()
+    cupcake_find_package("${file}" "${ARGN}")
+  endforeach()
 endfunction()
diff --git a/cmake/cupcake_json.cmake b/cmake/cupcake_json.cmake
index 77fb143..9b59603 100644
--- a/cmake/cupcake_json.cmake
+++ b/cmake/cupcake_json.cmake
@@ -19,15 +19,21 @@ function(cupcake_json_get variable type default json)
   set(${variable} "${value}" PARENT_SCOPE)
 endfunction()
 
-function(cupcake_json_to_list list array)
-  set(tmp "")
+function(cupcake_json_to_list variable array)
+  unset(list)
   string(JSON count LENGTH "${array}")
   if(count GREATER 0)
     math(EXPR stop "${count} - 1")
     foreach(i RANGE ${stop})
       string(JSON item GET "${array}" ${i})
-      list(APPEND tmp "${item}")
+      list(APPEND list "${item}")
     endforeach()
   endif()
-  set(${list} "${tmp}" PARENT_SCOPE)
+  set(${variable} "${list}" PARENT_SCOPE)
+endfunction()
+
+function(cupcake_json_get_list variable json)
+  cupcake_json_get(list ARRAY "[]" "${json}" ${ARGN})
+  cupcake_json_to_list(list "${list}")
+  set(${variable} "${list}" PARENT_SCOPE)
 endfunction()
diff --git a/cmake/cupcake_link_libraries.cmake b/cmake/cupcake_link_libraries.cmake
index d19f9af..c98fa92 100644
--- a/cmake/cupcake_link_libraries.cmake
+++ b/cmake/cupcake_link_libraries.cmake
@@ -8,25 +8,19 @@ include(cupcake_json)
 # TODO: Default `group` to `main`.
 function(cupcake_link_libraries target scope group)
   cupcake_assert_special()
-  cupcake_json_get(imports ARRAY "[]" "${PROJECT_JSON}" imports)
-  # imports :: [{ file :: string, targets :: [string] }]
-  string(JSON count LENGTH "${imports}")
-  if(count GREATER 0)
-    math(EXPR stop "${count} - 1")
-    foreach(i RANGE ${stop})
-      string(JSON import GET "${imports}" ${i})
-      # Select only imports whose `groups` (default: `["main"]`)
-      # contain `group`.
-      cupcake_json_get(groups ARRAY "[\"main\"]" "${import}" groups)
-      cupcake_json_to_list(groups "${groups}")
-      list(FIND groups "${group}" j)
-      if(j LESS 0)
-        continue()
-      endif()
-      string(JSON name GET "${import}" name)
-      cupcake_json_get(targets ARRAY "[\"${name}::${name}\"]" "${import}" targets)
-      cupcake_json_to_list(targets "${targets}")
-      target_link_libraries(${target} ${scope} ${targets})
-    endforeach()
-  endif()
+  cupcake_json_get_list(imports "${PROJECT_JSON}" imports)
+  foreach(import IN LISTS imports)
+    # import :: { file :: string, targets :: [string] }
+    # Select only imports whose `groups` (default: `["main"]`) contain `group`.
+    cupcake_json_get(groups ARRAY "[\"main\"]" "${import}" groups)
+    cupcake_json_to_list(groups "${groups}")
+    list(FIND groups "${group}" i)
+    if(i LESS 0)
+      continue()
+    endif()
+    string(JSON name GET "${import}" name)
+    cupcake_json_get(targets ARRAY "[\"${name}::${name}\"]" "${import}" targets)
+    cupcake_json_to_list(targets "${targets}")
+    target_link_libraries(${target} ${scope} ${targets})
+  endforeach()
 endfunction()

From 1f77ca11cf364ad14facb798b8cec035f1d1c6db Mon Sep 17 00:00:00 2001
From: John Freeman <jfreeman08@gmail.com>
Date: Wed, 6 Nov 2024 10:29:35 -0600
Subject: [PATCH 3/5] Fix external Conan component requirements

When generating Conan components as part of installing `cpp_info.py`,
fix the mapping from external CMake targets to external Conan components.
---
 cmake/cupcake_install_cpp_info.cmake       |  4 ++
 cmake/cupcake_project.cmake                | 45 ++++++++++++++
 cmake/data/install_cpp_info.cmake          |  3 +
 cmake/data/project_cpp_info/CMakeLists.txt | 70 +++++++++++++---------
 4 files changed, 94 insertions(+), 28 deletions(-)

diff --git a/cmake/cupcake_install_cpp_info.cmake b/cmake/cupcake_install_cpp_info.cmake
index ea9112f..b4ae729 100644
--- a/cmake/cupcake_install_cpp_info.cmake
+++ b/cmake/cupcake_install_cpp_info.cmake
@@ -1,6 +1,7 @@
 include_guard(GLOBAL)
 
 include(cupcake_module_dir)
+include(cupcake_project_properties)
 
 file(READ "${CUPCAKE_MODULE_DIR}/data/install_cpp_info.cmake"
   CUPCAKE_INSTALL_CPP_INFO
@@ -18,8 +19,11 @@ file(READ "${CUPCAKE_MODULE_DIR}/data/install_cpp_info.cmake"
 # package with `find_package` and then generates and installs a `cpp_info.py`
 # under `CMAKE_INSTALL_PREFIX`.
 function(cupcake_install_cpp_info)
+  cupcake_get_project_property(CONAN_COMPONENTS)
+  string(REPLACE "\"" "\\\"" CONAN_COMPONENTS "${CONAN_COMPONENTS}")
   install(
     CODE "
+set(CONAN_COMPONENTS \"${CONAN_COMPONENTS}\")
 set(CMAKE_BINARY_DIR \"${CMAKE_BINARY_DIR}\")
 set(PACKAGE_NAME ${PROJECT_NAME})
 string(TOUPPER $<CONFIG> CONFIG)
diff --git a/cmake/cupcake_project.cmake b/cmake/cupcake_project.cmake
index 8df2d2a..8bbc22a 100644
--- a/cmake/cupcake_project.cmake
+++ b/cmake/cupcake_project.cmake
@@ -1,5 +1,49 @@
 include_guard(GLOBAL)
 
+include(cupcake_json)
+include(cupcake_project_properties)
+
+# This is a function just to create a private scope for variables.
+function(_cupcake_parse_json json)
+  set(members "\"\":null")
+  # imports = json.get('imports', [])
+  cupcake_json_get_list(imports "${json}" imports)
+  foreach(import IN LISTS imports)
+    # import :: { root :: object, components :: object[] }
+
+    # if component := import['root']:
+    string(JSON component ERROR_VARIABLE error GET "${import}" root)
+    if(NOT error)
+      cupcake_parse_component(ms "${component}")
+      string(APPEND members "${ms}")
+    endif()
+
+    # components = import.get('components', [])
+    cupcake_json_get_list(components "${import}" components)
+    foreach(component IN LISTS components)
+      # component :: { name :: string, target :: string, aliases: string[] }
+      cupcake_parse_component(ms "${component}")
+      string(APPEND members "${ms}")
+    endforeach()
+
+  endforeach()
+  cupcake_set_project_property(PROPERTY CONAN_COMPONENTS "${members}")
+endfunction()
+
+function(cupcake_parse_component variable component)
+  string(JSON name GET "${component}" name)
+  string(JSON target GET "${component}" target)
+  # members[target] = name
+  set(members ",\"${target}\":\"${name}\"")
+  # aliases = component.get('aliases', []):
+  cupcake_json_get_list(aliases "${component}" aliases)
+  foreach(alias IN LISTS aliases)
+    # members[alias] = name
+    string(APPEND members ",\"${alias}\":\"${name}\"")
+  endforeach()
+  set(${variable} "${members}" PARENT_SCOPE)
+endfunction()
+
 macro(cupcake_project)
   # Allow `install(CODE)` to use generator expressions.
   cmake_policy(SET CMP0087 NEW)
@@ -126,6 +170,7 @@ macro(cupcake_project)
   if(EXISTS "${path}")
     file(READ "${path}" PROJECT_JSON)
     set(${PROJECT_NAME}_JSON "${PROJECT_JSON}")
+    _cupcake_parse_json("${PROJECT_JSON}")
   endif()
 
   set(${PROJECT_NAME}_FOUND 1)
diff --git a/cmake/data/install_cpp_info.cmake b/cmake/data/install_cpp_info.cmake
index a43fb05..cf4b18c 100644
--- a/cmake/data/install_cpp_info.cmake
+++ b/cmake/data/install_cpp_info.cmake
@@ -8,6 +8,7 @@
 # is `CMAKE_INSTALL_PREFIX`, because it can change at install time.
 
 set(parameters
+  CONAN_COMPONENTS
   CMAKE_BINARY_DIR
   PACKAGE_NAME
   CONFIG
@@ -25,6 +26,7 @@ if(missing_parameters)
   message(FATAL_ERROR "missing parameters: ${missing_parameters}")
 endif()
 
+message(STATUS "CONAN_COMPONENTS = '${CONAN_COMPONENTS}'")
 message(STATUS "CMAKE_BINARY_DIR = '${CMAKE_BINARY_DIR}'")
 message(STATUS "PACKAGE_NAME = '${PACKAGE_NAME}'")
 message(STATUS "CONFIG = '${CONFIG}'")
@@ -37,6 +39,7 @@ set(tmp_dir "${CMAKE_BINARY_DIR}/cpp_info")
 file(MAKE_DIRECTORY "${tmp_dir}")
 execute_process(
   COMMAND "${CMAKE_COMMAND}"
+    "-DCONAN_COMPONENTS=${CONAN_COMPONENTS}"
     "-DPACKAGE_NAME=${PACKAGE_NAME}"
     "-DCONFIG=${CONFIG}"
     # CMake complains if `CMAKE_BUILD_TYPE` is not set for
diff --git a/cmake/data/project_cpp_info/CMakeLists.txt b/cmake/data/project_cpp_info/CMakeLists.txt
index 6cc1687..e74ada0 100644
--- a/cmake/data/project_cpp_info/CMakeLists.txt
+++ b/cmake/data/project_cpp_info/CMakeLists.txt
@@ -23,13 +23,16 @@ string(APPEND cpp_info
   "self.set_property('cmake_find_mode', 'config')\n"
 )
 
-unset(buffer.log)
 macro(log level text)
-  message(${level} "${text}")
+  set(space " ")
+  if(level STREQUAL STATUS)
+    set(space "")
+  endif()
+  message(${level} "${space}${text}")
   string(APPEND buffer.log "# [${level}] ${text}\n")
 endmacro()
 
-set(pattern_scope "^([^:]+)::(.+)$")
+set(pattern_namespace "^([^:]+)::(.+)$")
 
 # For each library target, add Python statements to the script text
 # to declare these properties on a component named after the target:
@@ -43,22 +46,22 @@ set(pattern_scope "^([^:]+)::(.+)$")
 # - libs: singleton list of installed library name to be searched by linker
 # - libdirs: singleton list of directory, relative to the install prefix, where library is installed
 
-# `libraries` is the set of libraries that
+# `targets` is the set of CMake library targets that
 # have been or will be added as Conan components.
-set(libraries ${${PACKAGE_NAME}_LIBRARIES})
-# `targets` is the subset of `libraries` that
+set(targets ${${PACKAGE_NAME}_LIBRARIES})
+# `queue` is the subset of `targets` that
 # have not yet been added as Conan components.
-set(targets ${libraries})
-# On each iteration, we will remove one target from `targets`,
-# and add zero or more targets to `targets` and `libraries`
-# if they do not already appear in `libraries`.
-while(targets)
-  list(POP_FRONT targets target)
+set(queue ${targets})
+# On each iteration, we will remove one target from `queue`,
+# and add zero or more targets to `queue` and `targets`
+# if they do not already appear in `targets`.
+while(queue)
+  list(POP_FRONT queue target)
 
   # log(STATUS "target = ${target}")
 
   # Peel off the namespace to get the unqualified CMake target name.
-  string(REGEX MATCH "${pattern_scope}" match ${target})
+  string(REGEX MATCH "${pattern_namespace}" match ${target})
   if(NOT CMAKE_MATCH_1 STREQUAL PACKAGE_NAME)
     message(FATAL_ERROR "foreign target: '${target}'")
   endif()
@@ -66,7 +69,8 @@ while(targets)
   # Target name unqualified by package name.
   set(tname ${CMAKE_MATCH_2})
 
-  string(REGEX MATCH "${pattern_scope}" match ${tname})
+  # Type must be "libraries" or "imports".
+  string(REGEX MATCH "${pattern_namespace}" match ${tname})
   set(type ${CMAKE_MATCH_1})
   if(NOT (type STREQUAL "libraries" OR type STREQUAL "imports"))
     message(FATAL_ERROR "not a library: '${target}'")
@@ -74,10 +78,13 @@ while(targets)
 
   # Library name.
   set(name ${CMAKE_MATCH_2})
-  # Component name cannot contain double colon (::).
+  # Component name. Cannot contain double colon (::).
   set(cname ${type}.${name})
-  string(APPEND components "'${cname}',")
+  if(type STREQUAL "libraries")
+    string(APPEND library_components "'${cname}',")
+  endif()
 
+  # Generate external aliases.
   string(SUBSTRING ${type} 0 1 shorthand)
   set(aliases "'${PACKAGE_NAME}::${shorthand}::${name}'")
   if(type STREQUAL "libraries" AND name STREQUAL PACKAGE_NAME)
@@ -117,25 +124,28 @@ while(targets)
     # imported. It does not work when "importing" external libraries with
     # `add_subdirectory`. The subdirectory's targets would not be imported,
     # but would not be internal either, unless we install them.
-    string(REGEX MATCH "${pattern_scope}" match ${link})
+    string(REGEX MATCH "${pattern_namespace}" match ${link})
     if(CMAKE_MATCH_1 STREQUAL PACKAGE_NAME)
       # Internal target.
-      # Add it to `targets` (and `libraries`) if not yet in `libraries`.
-      list(FIND libraries "${link}" index)
+      # Add it to `queue` (and `targets`) if not yet in `targets`.
+      list(FIND targets "${link}" index)
       if(index LESS 0)
-        list(APPEND libraries "${link}")
         list(APPEND targets "${link}")
+        list(APPEND queue "${link}")
       endif()
       # Translate to Conan component name.
-      if(NOT CMAKE_MATCH_2 MATCHES "${pattern_scope}")
+      if(NOT CMAKE_MATCH_2 MATCHES "${pattern_namespace}")
         message(FATAL_ERROR "illegal internal target name: ${link}")
       endif()
       set(lname ${CMAKE_MATCH_1}.${CMAKE_MATCH_2})
     else()
       # External target.
-      # TODO: Find Conan component name in variable map `CUPCAKE_CONAN_COMPONENT`.
-      # TODO: Pre-populate `CUPCAKE_CONAN_COMPONENT` from `cupcake.json`.
-      set(lname ${link})
+      # Translate to Conan component name.
+      string(JSON lname ERROR_VARIABLE error GET "{${CONAN_COMPONENTS}}" "${link}")
+      if(error)
+        log(ERROR "${error}")
+        set(lname ${link})
+      endif()
     endif()
     list(APPEND requires "'${lname}'")
   endwhile()
@@ -181,10 +191,12 @@ while(targets)
     )
   endif()
 
+  get_target_property(options ${target} INTERFACE_LINK_OPTIONS)
   # LINK_FLAGS until CMake 3.13, then LINK_OPTIONS.
-  get_target_property(options ${target} LINK_OPTIONS)
-  if(NOT options)
-    get_target_property(options ${target} LINK_FLAGS)
+  get_target_property(flags ${target} LINK_FLAGS)
+  if(flags)
+    log(WARNING "LINK_FLAGS are deprecated. Found on ${target}")
+    list(APPEND options "${flags}")
   endif()
   if(options)
     foreach(option ${options})
@@ -212,9 +224,11 @@ while(targets)
   endif()
 endwhile()
 
+# TODO: Let other libraries be the default export.
 string(APPEND cpp_info
   "self.components['libraries'].set_property('cmake_target_name', '${PACKAGE_NAME}::libraries')\n"
-  "self.components['libraries'].requires = [${components}]\n"
+  "self.components['libraries'].set_property('default_export', True)\n"
+  "self.components['libraries'].requires = [${library_components}]\n"
   "${buffer.log}"
 )
 

From 0992a5e9c47f3ee4741eb0a5150e4e5a983bc830 Mon Sep 17 00:00:00 2001
From: John Freeman <jfreeman08@gmail.com>
Date: Wed, 6 Nov 2024 15:08:45 -0600
Subject: [PATCH 4/5] Fix quoting

---
 cmake/cupcake_add_executables.cmake |  3 ++-
 cmake/cupcake_add_libraries.cmake   |  3 ++-
 cmake/cupcake_add_tests.cmake       |  3 ++-
 cmake/cupcake_find_packages.cmake   |  3 ++-
 cmake/cupcake_json.cmake            | 17 +++++++++++++++++
 cmake/cupcake_link_libraries.cmake  |  4 +++-
 6 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/cmake/cupcake_add_executables.cmake b/cmake/cupcake_add_executables.cmake
index cc34897..f362ae4 100644
--- a/cmake/cupcake_add_executables.cmake
+++ b/cmake/cupcake_add_executables.cmake
@@ -29,7 +29,8 @@ function(cupcake_add_executables)
       #   | { target :: string, scope? :: PUBLIC | PRIVATE | INTERFACE }
       string(JSON type TYPE "${link}")
       if(type STREQUAL STRING)
-        set(target "${link}")
+        # A JSON string is already quoted.
+        set(target ${link})
         set(scope "PRIVATE")
       else()
         string(JSON target GET "${link}" target)
diff --git a/cmake/cupcake_add_libraries.cmake b/cmake/cupcake_add_libraries.cmake
index 8a513b5..00880b4 100644
--- a/cmake/cupcake_add_libraries.cmake
+++ b/cmake/cupcake_add_libraries.cmake
@@ -29,7 +29,8 @@ function(cupcake_add_libraries)
       #   | { target :: string, scope? :: PUBLIC | PRIVATE | INTERFACE }
       string(JSON type TYPE "${link}")
       if(type STREQUAL STRING)
-        set(target "${link}")
+        # A JSON string is already quoted.
+        set(target ${link})
         set(scope "PUBLIC")
       else()
         string(JSON target GET "${link}" target)
diff --git a/cmake/cupcake_add_tests.cmake b/cmake/cupcake_add_tests.cmake
index 1d3532b..55a101e 100644
--- a/cmake/cupcake_add_tests.cmake
+++ b/cmake/cupcake_add_tests.cmake
@@ -21,7 +21,8 @@ function(cupcake_add_tests)
       #   | { target :: string, scope? :: PUBLIC | PRIVATE | INTERFACE }
       string(JSON type TYPE "${link}")
       if(type STREQUAL STRING)
-        set(target "${link}")
+        # A JSON string is already quoted.
+        set(target ${link})
         set(scope "PRIVATE")
       else()
         string(JSON target GET "${link}" target)
diff --git a/cmake/cupcake_find_packages.cmake b/cmake/cupcake_find_packages.cmake
index 45f89d3..fe8fcb9 100644
--- a/cmake/cupcake_find_packages.cmake
+++ b/cmake/cupcake_find_packages.cmake
@@ -14,7 +14,8 @@ function(cupcake_find_packages group)
     # Select only imports whose `groups` (default: `["main"]`) contain `group`.
     cupcake_json_get(groups ARRAY "[\"main\"]" "${import}" groups)
     cupcake_json_to_list(groups "${groups}")
-    list(FIND groups "${group}" i)
+    # Group names are quoted JSON strings in the list.
+    list(FIND groups "\"${group}\"" i)
     if(i LESS 0)
       continue()
     endif()
diff --git a/cmake/cupcake_json.cmake b/cmake/cupcake_json.cmake
index 9b59603..a15ff53 100644
--- a/cmake/cupcake_json.cmake
+++ b/cmake/cupcake_json.cmake
@@ -26,6 +26,11 @@ function(cupcake_json_to_list variable array)
     math(EXPR stop "${count} - 1")
     foreach(i RANGE ${stop})
       string(JSON item GET "${array}" ${i})
+      string(JSON type TYPE "${array}" ${i})
+      if(type STREQUAL STRING)
+        # CMake automatically unquotes JSON strings. Re-quote them here.
+        set(item "\"${item}\"")
+      endif()
       list(APPEND list "${item}")
     endforeach()
   endif()
@@ -37,3 +42,15 @@ function(cupcake_json_get_list variable json)
   cupcake_json_to_list(list "${list}")
   set(${variable} "${list}" PARENT_SCOPE)
 endfunction()
+
+# Unquote all strings in a list.
+# unquote(variable [string...])
+function(cupcake_unquote variable)
+  foreach(string ${ARGN})
+    if(string MATCHES "^\"(.*)\"$")
+      set(string "${CMAKE_MATCH_1}")
+    endif()
+    string(APPEND list "${string}")
+  endforeach()
+  set(${variable} "${list}" PARENT_SCOPE)
+endfunction()
diff --git a/cmake/cupcake_link_libraries.cmake b/cmake/cupcake_link_libraries.cmake
index c98fa92..3873bcd 100644
--- a/cmake/cupcake_link_libraries.cmake
+++ b/cmake/cupcake_link_libraries.cmake
@@ -14,13 +14,15 @@ function(cupcake_link_libraries target scope group)
     # Select only imports whose `groups` (default: `["main"]`) contain `group`.
     cupcake_json_get(groups ARRAY "[\"main\"]" "${import}" groups)
     cupcake_json_to_list(groups "${groups}")
-    list(FIND groups "${group}" i)
+    # Group names are quoted JSON strings in the list.
+    list(FIND groups "\"${group}\"" i)
     if(i LESS 0)
       continue()
     endif()
     string(JSON name GET "${import}" name)
     cupcake_json_get(targets ARRAY "[\"${name}::${name}\"]" "${import}" targets)
     cupcake_json_to_list(targets "${targets}")
+    cupcake_unquote(targets "${targets}")
     target_link_libraries(${target} ${scope} ${targets})
   endforeach()
 endfunction()

From bac33bb6fe41ee44fa96d87f8b856269ccd0ba52 Mon Sep 17 00:00:00 2001
From: John Freeman <jfreeman08@gmail.com>
Date: Wed, 6 Nov 2024 15:11:58 -0600
Subject: [PATCH 5/5] Rename to EXTERNAL_CONAN_COMPONENTS

---
 cmake/cupcake_install_cpp_info.cmake       |  6 +++---
 cmake/cupcake_project.cmake                |  2 +-
 cmake/data/install_cpp_info.cmake          |  6 +++---
 cmake/data/project_cpp_info/CMakeLists.txt | 13 +++++++++++--
 conanfile.py                               |  1 +
 5 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/cmake/cupcake_install_cpp_info.cmake b/cmake/cupcake_install_cpp_info.cmake
index b4ae729..a004f9a 100644
--- a/cmake/cupcake_install_cpp_info.cmake
+++ b/cmake/cupcake_install_cpp_info.cmake
@@ -19,11 +19,11 @@ file(READ "${CUPCAKE_MODULE_DIR}/data/install_cpp_info.cmake"
 # package with `find_package` and then generates and installs a `cpp_info.py`
 # under `CMAKE_INSTALL_PREFIX`.
 function(cupcake_install_cpp_info)
-  cupcake_get_project_property(CONAN_COMPONENTS)
-  string(REPLACE "\"" "\\\"" CONAN_COMPONENTS "${CONAN_COMPONENTS}")
+  cupcake_get_project_property(EXTERNAL_CONAN_COMPONENTS)
+  string(REPLACE "\"" "\\\"" EXTERNAL_CONAN_COMPONENTS "${EXTERNAL_CONAN_COMPONENTS}")
   install(
     CODE "
-set(CONAN_COMPONENTS \"${CONAN_COMPONENTS}\")
+set(EXTERNAL_CONAN_COMPONENTS \"${EXTERNAL_CONAN_COMPONENTS}\")
 set(CMAKE_BINARY_DIR \"${CMAKE_BINARY_DIR}\")
 set(PACKAGE_NAME ${PROJECT_NAME})
 string(TOUPPER $<CONFIG> CONFIG)
diff --git a/cmake/cupcake_project.cmake b/cmake/cupcake_project.cmake
index 8bbc22a..e175a39 100644
--- a/cmake/cupcake_project.cmake
+++ b/cmake/cupcake_project.cmake
@@ -27,7 +27,7 @@ function(_cupcake_parse_json json)
     endforeach()
 
   endforeach()
-  cupcake_set_project_property(PROPERTY CONAN_COMPONENTS "${members}")
+  cupcake_set_project_property(PROPERTY EXTERNAL_CONAN_COMPONENTS "${members}")
 endfunction()
 
 function(cupcake_parse_component variable component)
diff --git a/cmake/data/install_cpp_info.cmake b/cmake/data/install_cpp_info.cmake
index cf4b18c..b39f122 100644
--- a/cmake/data/install_cpp_info.cmake
+++ b/cmake/data/install_cpp_info.cmake
@@ -8,7 +8,7 @@
 # is `CMAKE_INSTALL_PREFIX`, because it can change at install time.
 
 set(parameters
-  CONAN_COMPONENTS
+  # EXTERNAL_CONAN_COMPONENTS can be an empty string.
   CMAKE_BINARY_DIR
   PACKAGE_NAME
   CONFIG
@@ -26,7 +26,7 @@ if(missing_parameters)
   message(FATAL_ERROR "missing parameters: ${missing_parameters}")
 endif()
 
-message(STATUS "CONAN_COMPONENTS = '${CONAN_COMPONENTS}'")
+message(STATUS "EXTERNAL_CONAN_COMPONENTS = '${EXTERNAL_CONAN_COMPONENTS}'")
 message(STATUS "CMAKE_BINARY_DIR = '${CMAKE_BINARY_DIR}'")
 message(STATUS "PACKAGE_NAME = '${PACKAGE_NAME}'")
 message(STATUS "CONFIG = '${CONFIG}'")
@@ -39,7 +39,7 @@ set(tmp_dir "${CMAKE_BINARY_DIR}/cpp_info")
 file(MAKE_DIRECTORY "${tmp_dir}")
 execute_process(
   COMMAND "${CMAKE_COMMAND}"
-    "-DCONAN_COMPONENTS=${CONAN_COMPONENTS}"
+    "-DEXTERNAL_CONAN_COMPONENTS=${EXTERNAL_CONAN_COMPONENTS}"
     "-DPACKAGE_NAME=${PACKAGE_NAME}"
     "-DCONFIG=${CONFIG}"
     # CMake complains if `CMAKE_BUILD_TYPE` is not set for
diff --git a/cmake/data/project_cpp_info/CMakeLists.txt b/cmake/data/project_cpp_info/CMakeLists.txt
index e74ada0..5ab23b4 100644
--- a/cmake/data/project_cpp_info/CMakeLists.txt
+++ b/cmake/data/project_cpp_info/CMakeLists.txt
@@ -10,6 +10,12 @@ find_package(
   PATHS ${CMAKE_INSTALL_PREFIX}
 )
 
+# Do not warn for unused variables.
+if(EXTERNAL_CONAN_COMPONENTS)
+endif()
+if(CMAKE_POLICY_DEFAULT_CMP0091)
+endif()
+
 string(APPEND cpp_info
   # - names[generator]: namespace name
   "self.names['cmake_find_package'] = '${PACKAGE_NAME}'\n"
@@ -141,9 +147,12 @@ while(queue)
     else()
       # External target.
       # Translate to Conan component name.
-      string(JSON lname ERROR_VARIABLE error GET "{${CONAN_COMPONENTS}}" "${link}")
+      string(
+        JSON lname ERROR_VARIABLE error
+        GET "{${EXTERNAL_CONAN_COMPONENTS}}" "${link}"
+      )
       if(error)
-        log(ERROR "${error}")
+        log(ERROR "unrecognized target linked by ${target}: ${link}")
         set(lname ${link})
       endif()
     endif()
diff --git a/conanfile.py b/conanfile.py
index 2f84be9..116a90e 100644
--- a/conanfile.py
+++ b/conanfile.py
@@ -10,6 +10,7 @@ class Cupcake(ConanFile):
     license = 'ISC'
     author = 'John Freeman <jfreeman08@gmail.com>'
     url = 'https://github.com/thejohnfreeman/cupcake.cmake'
+    description = 'CMake boilerplate for an opinionated project structure.'
 
     # TODO: The CMake helper requires the build_type setting to run its build
     # or install methods.