Running CMake Configure twice on Linux results in different curl_config.h

[AllianceDarkSylinc]

I did this

It is quite common practice to run CMake configure more than once.
In fact super ultra common for IDEs like QtCreator.

The first run results in this file:

curl_config.first.run.h.zip

The second run results in this file:

curl_config.next.runs.h.zip

To be more concrete, the only 2 differences (at least on Ubuntu 18.04 LTS) are these:

#define CURL_CA_BUNDLE "/etc/ssl/certs/ca-certificates.crt"
#define CURL_CA_PATH "/etc/ssl/certs"

vs

/* #undef CURL_CA_BUNDLE */
/* #undef CURL_CA_PATH */

I expected the following

The first file should always be created

Why this happens?

This happens because the CMake script starts using CURL_CA_BUNDLE_SET as a temporary variable to drive logic.

But then once it's done it sets CURL_CA_BUNDLE_SET both as a user-configurable variable to drive logic, and a way to inform the user that the CA Bundle has been set.

So when the script is ran a 2nd time, it sees CURL_CA_BUNDLE_SET is set 'manually' (the code seems to assume it's been set by the user) and thus early outs from autodetecting the paths.

Solutions

I believe this is what's intended:

set(CURL_CA_BUNDLE_SET TRUE CACHE BOOL "Path to the CA bundle has been set")
set(CURL_CA_PATH "/etc/ssl/certs" CACHE STRING
		  "Location of default CA path. Set 'none' to disable or 'auto' for auto-detection. Defaults to 'auto'.")

It fixes the problem because now the script also remembers the path that were searched during the 1st run.

This is the patch:

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2ffb72faf..7ea5867b7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -851,7 +851,8 @@ elseif(CURL_CA_PATH_AUTODETECT OR CURL_CA_BUNDLE_AUTODETECT)
     foreach(SEARCH_CA_BUNDLE_PATH ${SEARCH_CA_BUNDLE_PATHS})
       if(EXISTS "${SEARCH_CA_BUNDLE_PATH}")
         message(STATUS "Found CA bundle: ${SEARCH_CA_BUNDLE_PATH}")
-        set(CURL_CA_BUNDLE "${SEARCH_CA_BUNDLE_PATH}")
+        set(CURL_CA_BUNDLE "${SEARCH_CA_BUNDLE_PATH}" CACHE STRING
+            "Path to the CA bundle. Set 'none' to disable or 'auto' for auto-detection. Defaults to 'auto'.")
         set(CURL_CA_BUNDLE_SET TRUE CACHE BOOL "Path to the CA bundle has been set")
         break()
       endif()
@@ -860,7 +861,8 @@ elseif(CURL_CA_PATH_AUTODETECT OR CURL_CA_BUNDLE_AUTODETECT)
 
   if(CURL_CA_PATH_AUTODETECT AND (NOT CURL_CA_PATH_SET))
     if(EXISTS "/etc/ssl/certs")
-      set(CURL_CA_PATH "/etc/ssl/certs")
+      set(CURL_CA_PATH "/etc/ssl/certs" CACHE STRING
+          "Location of default CA path. Set 'none' to disable or 'auto' for auto-detection. Defaults to 'auto'.")
       set(CURL_CA_PATH_SET TRUE CACHE BOOL "Path to the CA bundle has been set")
     endif()
   endif()

I can submit a PR if you want me to; but I'm not 100% if this is the intended solution.

Update: PR 7101 submitted

curl/libcurl version

curl-7.76.1.tar.bz2

Bug is present as of latest d845d39

operating system

Xubuntu 18.04 LTS
CMake version 3.20.2 (via snap)

Linux matias-ubuntu 5.11.0-051100-generic #202102142330 SMP Sun Feb 14 23:33:21 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux