[bug] cpp_info.requires fails when the same replacement is used multiple times in [replace_requires]

[valgur]

Describe the bug

Conan: 2.9.2
OS: Linux

When using the following [replace_requires] in the host profile (for cross-compilation, since system libs are not available there):

[replace_requires]
opengl/system: libglvnd/1.7.0
egl/system: libglvnd/1.7.0
glu/system: libglvnd/1.7.0

this version of libepoxy fails during the package_info() step with the following error:

ERROR: libepoxy/1.5.10: required component package 'egl::' not in dependencies

This only happens when both opengl/system and egl/system are being used simultaneously. The error disappears when either one of the dependencies is removed from either self.requires() or self.cpp_info.requires.

The error does not occur when self.cpp_info.requires is left unset entirely.

How to reproduce it

Here's a minimal example:

from conan import ConanFile

class EpoxyConan(ConanFile):
    name = "libepoxy"
    version = "0.1"
    settings = "os", "arch", "compiler", "build_type"

    def requirements(self):
        self.requires("opengl/system")
        self.requires("egl/system")

    def package_info(self):
        self.cpp_info.requires.append("opengl::opengl")
        self.cpp_info.requires.append("egl::egl")

and a sample profile:

[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.cppstd=17
compiler.libcxx=libstdc++11
compiler.version=11
os=Linux

[conf]
tools.build:compiler_executables={"c": "gcc-11", "cpp": "g++-11"}

[replace_requires]
opengl/system: libglvnd/1.7.0
egl/system: libglvnd/1.7.0
glu/system: libglvnd/1.7.0

[valgur]

diff --git a/conans/model/dependencies.py b/conans/model/dependencies.py
--- a/conans/model/dependencies.py	(revision fabc81498dd673a03fd86326e6c3e858f1f7c3cc)
+++ b/conans/model/dependencies.py	(date 1731674551386)
@@ -91,12 +91,15 @@
     def from_node(node):
         d = OrderedDict((require, ConanFileInterface(transitive.node.conanfile))
                         for require, transitive in node.transitive_deps.items())
+        cleanup = set()
         for old_req, new_req in node.replaced_requires.items():
-            existing = d.pop(new_req, None)
-            if existing is not None:
-                added_req = new_req.copy_requirement()
-                added_req.ref = RecipeReference.loads(old_req)
-                d[added_req] = existing
+            added_req = new_req.copy_requirement()
+            added_req.ref = RecipeReference.loads(old_req)
+            d[added_req] = d[new_req]
+            if added_req != new_req:
+                cleanup.add(new_req)
+        for new_req in cleanup:
+            del d[new_req]
         return ConanFileDependencies(d)
 
     def filter(self, require_filter, remove_system=True):

This current logic is broken if a new_req value is present multiple times in node.replaced_requires:

>> list(d)
[
    'libglvnd/1.7.0',
    'xorg/system',
    'xorg-proto/2024.1',
    'xorg-macros/1.20.0',
]
>> node.replaced_requires
{
    'egl/system': 'libglvnd/1.7.0',
    'opengl/system': 'libglvnd/1.7.0',
}

The added_req != new_req check is necessary for replace_requires like xorg/system: xorg/1.8.10, which don't change the ref name and evaluate to the same d dictionary item. These would otherwise get incorrectly removed by del d[new_req].

[memsharded]

Thanks for the hint @valgur!

I already started to work on it the other day, see develop2...memsharded:conan:fix/replace_requires_multiple (I think it was a couple of days ago), but I am out of office in a conference and I didn't have the time to report here.
I'll try to move it forward for next release, I'll try to summarize work after the weekend.