Improve ansible-galaxy error for InconsistentCandidate exception (#75235)

* Improve error for InconsistentCandidate exceptions

* Add test case for installing a collection with an inconsistent version

* Add test case for installing a collection that has a dependency with an inconsistent version

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>
Co-authored-by: Sviatoslav Sydorenko <webknjaz@redhat.com>

changelogs/fragments/75235-ansible-galaxy-inconsistent-candidate-error.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - ansible-galaxy - Improve error message from dependency resolution when a candidate has inconsistent requirements (https://github.com/ansible/ansible/issues/75139).

lib/ansible/galaxy/collection/__init__.py

@@ -113,6 +113,7 @@ from ansible.galaxy.dependency_resolution.dataclasses import (
 )
 from ansible.galaxy.dependency_resolution.errors import (
     CollectionDependencyResolutionImpossible,
+    CollectionDependencyInconsistentCandidate,
 )
 from ansible.galaxy.dependency_resolution.versioning import meets_requirements
 from ansible.module_utils.six import raise_from
@@ -1353,3 +1354,33 @@ def _resolve_depenency_map(
             AnsibleError('\n'.join(error_msg_lines)),
             dep_exc,
         )
+    except CollectionDependencyInconsistentCandidate as dep_exc:
+        parents = [
+            "%s.%s:%s" % (p.namespace, p.name, p.ver)
+            for p in dep_exc.criterion.iter_parent()
+            if p is not None
+        ]
+
+        error_msg_lines = [
+            (
+                'Failed to resolve the requested dependencies map. '
+                'Got the candidate {req.fqcn!s}:{req.ver!s} ({dep_origin!s}) '
+                'which didn\'t satisfy all of the following requirements:'.
+                format(
+                    req=dep_exc.candidate,
+                    dep_origin='direct request'
+                    if not parents else 'dependency of {parent!s}'.
+                    format(parent=', '.join(parents))
+                )
+            )
+        ]
+
+        for req in dep_exc.criterion.iter_requirement():
+            error_msg_lines.append(
+                '* {req.fqcn!s}:{req.ver!s}'.format(req=req)
+            )
+
+        raise raise_from(  # NOTE: Leading "raise" is a hack for mypy bug #9717
+            AnsibleError('\n'.join(error_msg_lines)),
+            dep_exc,
+        )

lib/ansible/galaxy/dependency_resolution/errors.py

@@ -8,4 +8,5 @@ __metaclass__ = type
 
 from resolvelib.resolvers import (
     ResolutionImpossible as CollectionDependencyResolutionImpossible,
+    InconsistentCandidate as CollectionDependencyInconsistentCandidate,
 )

test/integration/targets/ansible-galaxy-collection/tasks/install.yml

@@ -163,6 +163,81 @@
     - '"Installing ''namespace3.name:1.0.0'' to" in install_tarball.stdout'
     - (install_tarball_actual.content | b64decode | from_json).collection_info.version == '1.0.0'
 
+- name: write a requirements file using the artifact and a conflicting version
+  copy:
+    content: |
+            collections:
+              - name: {{ galaxy_dir }}/namespace3.tar.gz
+                version: 1.2.0
+    dest: '{{ galaxy_dir }}/test_req.yml'
+
+- name: install the requirements file with mismatched versions
+  command: ansible-galaxy collection install -r '{{ galaxy_dir }}/test_req.yml' {{ galaxy_verbosity }}
+  ignore_errors: True
+  register: result
+
+- name: remove the requirements file
+  file:
+    path: '{{ galaxy_dir }}/test_req.yml'
+    state: absent
+
+- assert:
+    that: error == expected_error
+  vars:
+    reset_color: '\x1b\[0m'
+    color: '\x1b\[[0-9];[0-9]{2}m'
+    error: "{{ result.stderr | regex_replace(reset_color) | regex_replace(color) | regex_replace('\\n', ' ') }}"
+    expected_error: >-
+            ERROR! Failed to resolve the requested dependencies map.
+            Got the candidate namespace3.name:1.0.0 (direct request)
+            which didn't satisfy all of the following requirements:
+            * namespace3.name:1.2.0
+
+- name: test error for mismatched dependency versions
+  vars:
+    reset_color: '\x1b\[0m'
+    color: '\x1b\[[0-9];[0-9]{2}m'
+    error: "{{ result.stderr | regex_replace(reset_color) | regex_replace(color) | regex_replace('\\n', ' ') }}"
+    expected_error: >-
+            ERROR! Failed to resolve the requested dependencies map.
+            Got the candidate namespace3.name:1.0.0 (dependency of tmp_parent.name:1.0.0)
+            which didn't satisfy all of the following requirements:
+            * namespace3.name:1.2.0
+  block:
+    - name: init a new parent collection
+      command: ansible-galaxy collection init tmp_parent.name --init-path '{{ galaxy_dir }}/scratch'
+
+    - name: replace the dependencies
+      lineinfile:
+        path: "{{ galaxy_dir }}/scratch/tmp_parent/name/galaxy.yml"
+        regexp: "^dependencies:*"
+        line: "dependencies: { '{{ galaxy_dir }}/namespace3.tar.gz': '1.2.0' }"
+
+    - name: build the new artifact
+      command: ansible-galaxy collection build {{ galaxy_dir }}/scratch/tmp_parent/name
+      args:
+        chdir: "{{ galaxy_dir }}"
+
+    - name: install the artifact to verify the error is handled
+      command: ansible-galaxy collection install '{{ galaxy_dir }}/tmp_parent-name-1.0.0.tar.gz'
+      ignore_errors: yes
+      register: result
+
+    - debug: msg="Actual - {{ error }}"
+
+    - debug: msg="Expected - {{ expected_error }}"
+
+    - assert:
+        that: error == expected_error
+  always:
+    - name: clean up collection skeleton and artifact
+      file:
+        state: absent
+        path: "{{ item }}"
+      loop:
+        - "{{ galaxy_dir }}/scratch/tmp_parent/"
+        - "{{ galaxy_dir }}/tmp_parent-name-1.0.0.tar.gz"
+
 - name: setup bad tarball - {{ test_name }}
   script: build_bad_tar.py {{ galaxy_dir | quote }}