test(pkg): reproduce duplicate platform failures

test/blackbox-tests/test-cases/pkg/portable-lockdirs/portable-lockdirs-duplicate-platforms.t

@@ -0,0 +1,51 @@
+Duplicate entries in solve_for_platforms currently break result merging. Record the
+failure before joint solving deduplicates the requested platform set.
+
+  $ mkrepo
+  $ add_mock_repo_if_needed
+
+Make a package:
+  $ mkpkg foo <<EOF
+  > build: [
+  >   ["mkdir" "-p" "%{lib}%/%{name}%"]
+  >   ["touch" "%{lib}%/%{name}%/META"] # needed for dune to recognize this as a library
+  > ]
+  > EOF
+
+  $ make_portable_lockdirs_project
+
+Solve for a platform set that contains the same platform twice:
+  $ cat > dune-workspace <<EOF
+  > (lang dune 3.11)
+  > (repository
+  >  (name mock)
+  >  (url "file://$(pwd)/mock-opam-repository"))
+  > (lock_dir
+  >  (repositories mock)
+  >  (solve_for_platforms
+  >   ((arch arm64) (os macos))
+  >   ((arch arm64) (os macos))
+  >   ((arch x86_64) (os linux))))
+  > EOF
+
+Merging successful per-platform results rejects the duplicate solver
+environment:
+
+  $ dune pkg lock >output 2>&1
+  [1]
+  $ grep 'Tried to add duplicate solver env' output
+    ("Tried to add duplicate solver env to lockdir conditional choice",
+
+When solving fails before result merging, the duplicate platform is reported
+twice:
+
+  $ mkpkg foo <<'EOF'
+  > available: false
+  > EOF
+  $ dune pkg lock >output 2>&1
+  [1]
+  $ grep 'arch = arm64; os = macos' output
+  - arch = arm64; os = macos
+  - arch = arm64; os = macos
+  $ grep 'arch = x86_64; os = linux' output
+  - arch = x86_64; os = linux

test/blackbox-tests/test-cases/pkg/portable-lockdirs/portable-lockdirs-ignore-malformed-unselectable-version.t

@@ -0,0 +1,28 @@
+A malformed repository version that cannot satisfy a local package constraint
+must not prevent the solver from selecting a valid version.
+
+  $ mkrepo
+  $ add_mock_repo_if_needed
+
+  $ mkpkg foo 1 <<'EOF'
+  > EOF
+
+Version 2 is malformed, but the local constraint makes it impossible before its
+manifest needs to be loaded.
+
+  $ mkpkg foo 2 <<'EOF'
+  > depends: [
+  > EOF
+
+  $ cat >dune-project <<'EOF'
+  > (lang dune 3.18)
+  > (package
+  >  (name x)
+  >  (depends (foo (= 1))))
+  > EOF
+
+  $ dune pkg lock
+  Solution for dune.lock
+
+  Dependencies common to all supported platforms:
+  - foo.1

test/blackbox-tests/test-cases/pkg/portable-lockdirs/portable-lockdirs-local-platform-alternative-selection.t

@@ -0,0 +1,47 @@
+A local package dependency alternative may select a different package on each
+platform. Preserve every package selected by the per-platform solves when
+constructing the portable lock directory.
+
+  $ mkrepo
+  $ add_mock_repo_if_needed
+
+  $ mkpkg linux-impl <<'EOF'
+  > available: os = "linux"
+  > EOF
+  $ mkpkg macos-impl <<'EOF'
+  > available: os = "macos"
+  > EOF
+
+The local package accepts either implementation. Package availability forces
+Linux and macOS to select different branches of the disjunction.
+
+  $ cat >dune-project <<'EOF'
+  > (lang dune 3.18)
+  > EOF
+  $ cat >x.opam <<'EOF'
+  > opam-version: "2.0"
+  > depends: [ "linux-impl" | "macos-impl" ]
+  > EOF
+
+  $ dune pkg lock
+  Solution for dune.lock
+
+  Dependencies common to all supported platforms:
+  (none)
+
+  Additionally, some packages will only be built on specific platforms.
+
+  arch = arm64; os = linux:
+  - linux-impl.0.0.1
+
+  arch = arm64; os = macos:
+  - macos-impl.0.0.1
+
+  arch = x86_64; os = linux:
+  - linux-impl.0.0.1
+
+  arch = x86_64; os = macos:
+  - macos-impl.0.0.1
+  $ ls dune.lock/*.pkg | sort
+  dune.lock/linux-impl.0.0.1.pkg
+  dune.lock/macos-impl.0.0.1.pkg