Recover the complicated situation after my bad merge

I made a mistake merge.  Reverting it in c778945806b undid the state
on master, but now I realize it crippled the git merge mechanism.
As the merge contained a mix of commits from `master..staging-next`
and other commits from `staging-next..staging`, it got the
`staging-next` branch into a state that was difficult to recover.

I reconstructed the "desired" state of staging-next tree by:
 - checking out the last commit of the problematic range: 4effe769e2b
 - `git rebase -i --preserve-merges a8a018ddc0` - dropping the mistaken
   merge commit and its revert from that range (while keeping
   reapplication from 4effe769e2)
 - merging the last unaffected staging-next commit (803ca85c209)
 - fortunately no other commits have been pushed to staging-next yet
 - applying a diff on staging-next to get it into that state

2 files changed, 127 insertions, 0 deletions

diff --git a/pkgs/test/default.nix b/pkgs/test/default.nix
index 85142090dd42..d9befb9350ad 100644
--- a/pkgs/test/default.nix
+++ b/pkgs/test/default.nix
@@ -27,6 +27,8 @@ with pkgs;
   cc-multilib-gcc = callPackage ./cc-wrapper/multilib.nix { stdenv = gccMultiStdenv; };
   cc-multilib-clang = callPackage ./cc-wrapper/multilib.nix { stdenv = clangMultiStdenv; };
 
+  install-shell-files = callPackage ./install-shell-files {};
+
   kernel-config = callPackage ./kernel.nix {};
 
   ld-library-path = callPackage ./ld-library-path {};
diff --git a/pkgs/test/install-shell-files/default.nix b/pkgs/test/install-shell-files/default.nix
new file mode 100644
index 000000000000..e3729c7d2504
--- /dev/null
+++ b/pkgs/test/install-shell-files/default.nix
@@ -0,0 +1,125 @@
+{ stdenv, runCommandLocal, recurseIntoAttrs, installShellFiles }:
+
+let
+  runTest = name: env: buildCommand:
+    runCommandLocal "install-shell-files--${name}" ({
+      nativeBuildInputs = [ installShellFiles ];
+      meta.platforms = stdenv.lib.platforms.all;
+    } // env) buildCommand;
+in
+
+recurseIntoAttrs {
+  # installManPage
+
+  install-manpage = runTest "install-manpage" {} ''
+    mkdir -p doc
+    echo foo > doc/foo.1
+    echo bar > doc/bar.2.gz
+    echo baz > doc/baz.3
+
+    installManPage doc/*
+
+    cmp doc/foo.1 $out/share/man/man1/foo.1
+    cmp doc/bar.2.gz $out/share/man/man2/bar.2.gz
+    cmp doc/baz.3 $out/share/man/man3/baz.3
+  '';
+  install-manpage-outputs = runTest "install-manpage-outputs" {
+    outputs = [ "out" "man" "devman" ];
+  } ''
+    mkdir -p doc
+    echo foo > doc/foo.1
+    echo bar > doc/bar.3
+
+    installManPage doc/*
+
+    # assert they didn't go into $out
+    [[ ! -f $out/share/man/man1/foo.1 && ! -f $out/share/man/man3/bar.3 ]]
+
+    # foo.1 alone went into man
+    cmp doc/foo.1 ''${!outputMan:?}/share/man/man1/foo.1
+    [[ ! -f ''${!outputMan:?}/share/man/man3/bar.3 ]]
+
+    # bar.3 alone went into devman
+    cmp doc/bar.3 ''${!outputDevman:?}/share/man/man3/bar.3
+    [[ ! -f ''${!outputDevman:?}/share/man/man1/foo.1 ]]
+
+    touch $out
+  '';
+
+  # installShellCompletion
+
+  install-completion = runTest "install-completion" {} ''
+    echo foo > foo
+    echo bar > bar
+    echo baz > baz
+    echo qux > qux.zsh
+    echo quux > quux
+
+    installShellCompletion --bash foo bar --zsh baz qux.zsh --fish quux
+
+    cmp foo $out/share/bash-completion/completions/foo
+    cmp bar $out/share/bash-completion/completions/bar
+    cmp baz $out/share/zsh/site-functions/_baz
+    cmp qux.zsh $out/share/zsh/site-functions/_qux
+    cmp quux $out/share/fish/vendor_completions.d/quux
+  '';
+  install-completion-output = runTest "install-completion-output" {
+    outputs = [ "out" "bin" ];
+  } ''
+    echo foo > foo
+
+    installShellCompletion --bash foo
+
+    # assert it didn't go into $out
+    [[ ! -f $out/share/bash-completion/completions/foo ]]
+
+    cmp foo ''${!outputBin:?}/share/bash-completion/completions/foo
+
+    touch $out
+  '';
+  install-completion-name = runTest "install-completion-name" {} ''
+    echo foo > foo
+    echo bar > bar
+    echo baz > baz
+
+    installShellCompletion --bash --name foobar.bash foo --zsh --name _foobar bar --fish baz
+
+    cmp foo $out/share/bash-completion/completions/foobar.bash
+    cmp bar $out/share/zsh/site-functions/_foobar
+    cmp baz $out/share/fish/vendor_completions.d/baz
+  '';
+  install-completion-inference = runTest "install-completion-inference" {} ''
+    echo foo > foo.bash
+    echo bar > bar.zsh
+    echo baz > baz.fish
+
+    installShellCompletion foo.bash bar.zsh baz.fish
+
+    cmp foo.bash $out/share/bash-completion/completions/foo.bash
+    cmp bar.zsh $out/share/zsh/site-functions/_bar
+    cmp baz.fish $out/share/fish/vendor_completions.d/baz.fish
+  '';
+  install-completion-cmd = runTest "install-completion-cmd" {} ''
+    echo foo > foo.bash
+    echo bar > bar.zsh
+    echo baz > baz.fish
+    echo qux > qux.fish
+
+    installShellCompletion --cmd foobar --bash foo.bash --zsh bar.zsh --fish baz.fish --name qux qux.fish
+
+    cmp foo.bash $out/share/bash-completion/completions/foobar.bash
+    cmp bar.zsh $out/share/zsh/site-functions/_foobar
+    cmp baz.fish $out/share/fish/vendor_completions.d/foobar.fish
+    cmp qux.fish $out/share/fish/vendor_completions.d/qux
+  '';
+  install-completion-fifo = runTest "install-completion-fifo" {} ''
+    installShellCompletion \
+      --bash --name foo.bash <(echo foo) \
+      --zsh --name _foo <(echo bar) \
+      --fish --name foo.fish <(echo baz)
+
+    [[ $(<$out/share/bash-completion/completions/foo.bash) == foo ]] || { echo "foo.bash comparison failed"; exit 1; }
+    [[ $(<$out/share/zsh/site-functions/_foo) == bar ]] || { echo "_foo comparison failed"; exit 1; }
+    [[ $(<$out/share/fish/vendor_completions.d/foo.fish) == baz ]] || { echo "foo.fish comparison failed"; exit 1; }
+  '';
+}