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

52 files changed, 667 insertions, 1750 deletions

diff --git a/doc/stdenv/stdenv.xml b/doc/stdenv/stdenv.xml
index 4c069b57edd7..46ee97927eac 100644
--- a/doc/stdenv/stdenv.xml
+++ b/doc/stdenv/stdenv.xml
@@ -2070,7 +2070,7 @@ nativeBuildInputs = [ breakpointHook ];
        The <literal>installManPage</literal> function takes one or more paths to manpages to install. The manpages must have a section suffix, and may optionally be compressed (with <literal>.gz</literal> suffix). This function will place them into the correct directory.
       </para>
       <para>
-       The <literal>installShellCompletion</literal> function takes one or more paths to shell completion files. By default it will autodetect the shell type from the completion file extension, but you may also specify it by passing one of <literal>--bash</literal>, <literal>--fish</literal>, or <literal>--zsh</literal>. These flags apply to all paths listed after them (up until another shell flag is given). Each path may also have a custom installation name provided by providing a flag <literal>--name NAME</literal> before the path. If this flag is not provided, zsh completions will be renamed automatically such that <literal>foobar.zsh</literal> becomes <literal>_foobar</literal>.
+       The <literal>installShellCompletion</literal> function takes one or more paths to shell completion files. By default it will autodetect the shell type from the completion file extension, but you may also specify it by passing one of <literal>--bash</literal>, <literal>--fish</literal>, or <literal>--zsh</literal>. These flags apply to all paths listed after them (up until another shell flag is given). Each path may also have a custom installation name provided by providing a flag <literal>--name NAME</literal> before the path. If this flag is not provided, zsh completions will be renamed automatically such that <literal>foobar.zsh</literal> becomes <literal>_foobar</literal>. A root name may be provided for all paths using the flag <literal>--cmd NAME</literal>; this synthesizes the appropriate name depending on the shell (e.g. <literal>--cmd foo</literal> will synthesize the name <literal>foo.bash</literal> for bash and <literal>_foo</literal> for zsh). The path may also be a fifo or named fd (such as produced by <literal>&lt;(cmd)</literal>), in which case the shell and name must be provided.
 <programlisting>
 nativeBuildInputs = [ installShellFiles ];
 postInstall = ''
@@ -2081,6 +2081,11 @@ postInstall = ''
   installShellCompletion --zsh --name _foobar share/completions.zsh
   # implicit behavior
   installShellCompletion share/completions/foobar.{bash,fish,zsh}
+  # using named fd
+  installShellCompletion --cmd foobar \
+    --bash &lt;($out/bin/foobar --bash-completion) \
+    --fish &lt;($out/bin/foobar --fish-completion) \
+    --zsh &lt;($out/bin/foobar --zsh-completion)
 '';
 </programlisting>
       </para>
diff --git a/pkgs/applications/version-management/git-and-tools/git/default.nix b/pkgs/applications/version-management/git-and-tools/git/default.nix
index 7e40366142a9..49dc7866dbd5 100644
--- a/pkgs/applications/version-management/git-and-tools/git/default.nix
+++ b/pkgs/applications/version-management/git-and-tools/git/default.nix
@@ -22,7 +22,7 @@ assert sendEmailSupport -> perlSupport;
 assert svnSupport -> perlSupport;
 
 let
-  version = "2.28.0";
+  version = "2.29.0";
   svn = subversionClient.override { perlBindings = perlSupport; };
 
   gitwebPerlLibs = with perlPackages; [ CGI HTMLParser CGIFast FCGI FCGIProcManager HTMLTagCloud ];
@@ -34,7 +34,7 @@ stdenv.mkDerivation {
 
   src = fetchurl {
     url = "https://www.kernel.org/pub/software/scm/git/git-${version}.tar.xz";
-    sha256 = "17a311vzimqn1glc9d7x82rhb1mb81m5rr4g8xji8idaafid39fz";
+    sha256 = "KEMtmVJXxGJv4PsgkfWI327tmOlXFBnnLIO8Izcua4k=";
   };
 
   outputs = [ "out" ] ++ stdenv.lib.optional withManual "doc";
diff --git a/pkgs/build-support/install-shell-files/default.nix b/pkgs/build-support/install-shell-files/default.nix
index e1f2e24dd875..d50661ddc65d 100644
--- a/pkgs/build-support/install-shell-files/default.nix
+++ b/pkgs/build-support/install-shell-files/default.nix
@@ -1,4 +1,12 @@
-{ makeSetupHook }:
+{ makeSetupHook, tests }:
 
 # See the header comment in ../setup-hooks/install-shell-files.sh for example usage.
-makeSetupHook { name = "install-shell-files"; } ../setup-hooks/install-shell-files.sh
+let
+  setupHook = makeSetupHook { name = "install-shell-files"; } ../setup-hooks/install-shell-files.sh;
+in
+
+setupHook.overrideAttrs (oldAttrs: {
+  passthru = (oldAttrs.passthru or {}) // {
+    tests = tests.install-shell-files;
+  };
+})
diff --git a/pkgs/build-support/setup-hooks/install-shell-files.sh b/pkgs/build-support/setup-hooks/install-shell-files.sh
index e0ea1f7f30a7..194b408b1050 100644
--- a/pkgs/build-support/setup-hooks/install-shell-files.sh
+++ b/pkgs/build-support/setup-hooks/install-shell-files.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+# shellcheck shell=bash
 # Setup hook for the `installShellFiles` package.
 #
 # Example usage in a derivation:
@@ -19,8 +19,8 @@
 # installManPage <path> [...<path>]
 #
 # Each argument is checked for its man section suffix and installed into the appropriate
-# share/man<n>/ directory. The function returns an error if any paths don't have the man section
-# suffix (with optional .gz compression).
+# share/man/man<n>/ directory. The function returns an error if any paths don't have the man
+# section suffix (with optional .gz compression).
 installManPage() {
     local path
     for path in "$@"; do
@@ -49,7 +49,7 @@ installManPage() {
     done
 }
 
-# installShellCompletion [--bash|--fish|--zsh] ([--name <name>] <path>)...
+# installShellCompletion [--cmd <name>] ([--bash|--fish|--zsh] [--name <name>] <path>)...
 #
 # Each path is installed into the appropriate directory for shell completions for the given shell.
 # If one of `--bash`, `--fish`, or `--zsh` is given the path is assumed to belong to that shell.
@@ -61,9 +61,20 @@ installManPage() {
 # If the shell completion needs to be renamed before installing the optional `--name <name>` flag
 # may be given. Any name provided with this flag only applies to the next path.
 #
+# If all shell completions need to be renamed before installing the optional `--cmd <name>` flag
+# may be given. This will synthesize a name for each file, unless overridden with an explicit
+# `--name` flag. For example, `--cmd foobar` will synthesize the name `_foobar` for zsh and
+# `foobar.bash` for bash.
+#
 # For zsh completions, if the `--name` flag is not given, the path will be automatically renamed
 # such that `foobar.zsh` becomes `_foobar`.
 #
+# A path may be a named fd, such as produced by the bash construct `<(cmd)`. When using a named fd,
+# the shell type flag must be provided, and either the `--name` or `--cmd` flag must be provided.
+# This might look something like:
+#
+#   installShellCompletion --zsh --name _foobar <($out/bin/foobar --zsh-completion)
+#
 # This command accepts multiple shell flags in conjunction with multiple paths if you wish to
 # install them all in one command:
 #
@@ -76,9 +87,16 @@ installManPage() {
 #   installShellCompletion --fish --name foobar.fish share/completions.fish
 #   installShellCompletion --zsh --name _foobar share/completions.zsh
 #
+# Or to use shell newline escaping to split a single invocation across multiple lines:
+#
+#   installShellCompletion --cmd foobar \
+#     --bash <($out/bin/foobar --bash-completion) \
+#     --fish <($out/bin/foobar --fish-completion) \
+#     --zsh <($out/bin/foobar --zsh-completion)
+#
 # If any argument is `--` the remaining arguments will be treated as paths.
 installShellCompletion() {
-    local shell='' name='' retval=0 parseArgs=1 arg
+    local shell='' name='' cmdname='' retval=0 parseArgs=1 arg
     while { arg=$1; shift; }; do
         # Parse arguments
         if (( parseArgs )); then
@@ -97,6 +115,17 @@ installShellCompletion() {
                 # treat `--name=foo` the same as `--name foo`
                 name=${arg#--name=}
                 continue;;
+            --cmd)
+                cmdname=$1
+                shift || {
+                    echo 'installShellCompletion: error: --cmd flag expected an argument' >&2
+                    return 1
+                }
+                continue;;
+            --cmd=*)
+                # treat `--cmd=foo` the same as `--cmd foo`
+                cmdname=${arg#--cmd=}
+                continue;;
             --?*)
                 echo "installShellCompletion: warning: unknown flag ${arg%%=*}" >&2
                 retval=2
@@ -110,39 +139,67 @@ installShellCompletion() {
         if (( "${NIX_DEBUG:-0}" >= 1 )); then
             echo "installShellCompletion: installing $arg${name:+ as $name}"
         fi
-        # if we get here, this is a path
-        # Identify shell
-        local basename
-        basename=$(stripHash "$arg")
+        # if we get here, this is a path or named pipe
+        # Identify shell and output name
         local curShell=$shell
-        if [[ -z "$curShell" ]]; then
-            # auto-detect the shell
-            case "$basename" in
-            ?*.bash) curShell=bash;;
-            ?*.fish) curShell=fish;;
-            ?*.zsh) curShell=zsh;;
+        local outName=''
+        if [[ -z "$arg" ]]; then
+            echo "installShellCompletion: error: empty path is not allowed" >&2
+            return 1
+        elif [[ -p "$arg" ]]; then
+            # this is a named fd or fifo
+            if [[ -z "$curShell" ]]; then
+                echo "installShellCompletion: error: named pipe requires one of --bash, --fish, or --zsh" >&2
+                return 1
+            elif [[ -z "$name" && -z "$cmdname" ]]; then
+                echo "installShellCompletion: error: named pipe requires one of --cmd or --name" >&2
+                return 1
+            fi
+        else
+            # this is a path
+            local argbase
+            argbase=$(stripHash "$arg")
+            if [[ -z "$curShell" ]]; then
+                # auto-detect the shell
+                case "$argbase" in
+                ?*.bash) curShell=bash;;
+                ?*.fish) curShell=fish;;
+                ?*.zsh) curShell=zsh;;
+                *)
+                    if [[ "$argbase" = _* && "$argbase" != *.* ]]; then
+                        # probably zsh
+                        echo "installShellCompletion: warning: assuming path \`$arg' is zsh; please specify with --zsh" >&2
+                        curShell=zsh
+                    else
+                        echo "installShellCompletion: warning: unknown shell for path: $arg" >&2
+                        retval=2
+                        continue
+                    fi;;
+                esac
+            fi
+            outName=$argbase
+        fi
+        # Identify output path
+        if [[ -n "$name" ]]; then
+            outName=$name
+        elif [[ -n "$cmdname" ]]; then
+            case "$curShell" in
+            bash|fish) outName=$cmdname.$curShell;;
+            zsh) outName=_$cmdname;;
             *)
-                if [[ "$basename" = _* && "$basename" != *.* ]]; then
-                    # probably zsh
-                    echo "installShellCompletion: warning: assuming path \`$arg' is zsh; please specify with --zsh" >&2
-                    curShell=zsh
-                else
-                    echo "installShellCompletion: warning: unknown shell for path: $arg" >&2
-                    retval=2
-                    continue
-                fi;;
+                # Our list of shells is out of sync with the flags we accept or extensions we detect.
+                echo 'installShellCompletion: internal error' >&2
+                return 1;;
             esac
         fi
-        # Identify output path
-        local outName sharePath
-        outName=${name:-$basename}
+        local sharePath
         case "$curShell" in
         bash) sharePath=bash-completion/completions;;
         fish) sharePath=fish/vendor_completions.d;;
         zsh)
             sharePath=zsh/site-functions
             # only apply automatic renaming if we didn't have a manual rename
-            if test -z "$name"; then
+            if [[ -z "$name" && -z "$cmdname" ]]; then
                 # convert a name like `foo.zsh` into `_foo`
                 outName=${outName%.zsh}
                 outName=_${outName#_}
@@ -153,8 +210,16 @@ installShellCompletion() {
             return 1;;
         esac
         # Install file
-        install -Dm644 -T "$arg" "${!outputBin:?}/share/$sharePath/$outName" || return
-        # Clear the name, it only applies to one path
+        local outDir="${!outputBin:?}/share/$sharePath"
+        local outPath="$outDir/$outName"
+        if [[ -p "$arg" ]]; then
+            # install handles named pipes on NixOS but not on macOS
+            mkdir -p "$outDir" \
+            && cat "$arg" > "$outPath"
+        else
+            install -Dm644 -T "$arg" "$outPath"
+        fi || return
+        # Clear the per-path flags
         name=
     done
     if [[ -n "$name" ]]; then
diff --git a/pkgs/data/misc/tzdata/default.nix b/pkgs/data/misc/tzdata/default.nix
index 367ee06390cd..dc80580ff5ec 100644
--- a/pkgs/data/misc/tzdata/default.nix
+++ b/pkgs/data/misc/tzdata/default.nix
@@ -2,16 +2,16 @@
 
 stdenv.mkDerivation rec {
   pname = "tzdata";
-  version = "2019c";
+  version = "2020c";
 
   srcs =
     [ (fetchurl {
         url = "https://data.iana.org/time-zones/releases/tzdata${version}.tar.gz";
-        sha256 = "0z7w1yv37cfk8yhix2cillam091vgp1j4g8fv84261q9mdnq1ivr";
+        sha256 = "1nab36g5ibs88wg2mzpzygi1wh5gh2al1qjvbk8sb90sbw8ar43q";
       })
       (fetchurl {
         url = "https://data.iana.org/time-zones/releases/tzcode${version}.tar.gz";
-        sha256 = "1m3y2rnf1nggxxhxplab5zdd5whvar3ijyrv7lifvm82irkd7szn";
+        sha256 = "1r5zrk1k3jhhilkhrx82fd19rvysji8jk05gq5v0rndmyx07zacs";
       })
     ];
 
diff --git a/pkgs/development/compilers/gcc/builder.sh b/pkgs/development/compilers/gcc/builder.sh
index 2204744a4b59..e1c4768413f4 100644
--- a/pkgs/development/compilers/gcc/builder.sh
+++ b/pkgs/development/compilers/gcc/builder.sh
@@ -287,7 +287,12 @@ postInstall() {
     done
 
     # Two identical man pages are shipped (moving and compressing is done later)
-    ln -sf gcc.1 "$out"/share/man/man1/g++.1
+    for i in "$out"/share/man/man1/*g++.1; do
+        if test -e "$i"; then
+            man_prefix=`echo "$i" | sed "s,.*/\(.*\)g++.1,\1,"`
+            ln -sf "$man_prefix"gcc.1 "$i"
+        fi
+    done
 }
 
 genericBuild
diff --git a/pkgs/development/compilers/purescript/psc-package/default.nix b/pkgs/development/compilers/purescript/psc-package/default.nix
index 0bebd5d2f50d..88f7adce5a1a 100644
--- a/pkgs/development/compilers/purescript/psc-package/default.nix
+++ b/pkgs/development/compilers/purescript/psc-package/default.nix
@@ -44,12 +44,10 @@ stdenv.mkDerivation rec {
   '' + ''
     chmod u-w $PSC_PACKAGE
 
-    $PSC_PACKAGE --bash-completion-script $PSC_PACKAGE > psc-package.bash
-    $PSC_PACKAGE --fish-completion-script $PSC_PACKAGE > psc-package.fish
-    $PSC_PACKAGE --zsh-completion-script $PSC_PACKAGE > _psc-package
-    installShellCompletion \
-      psc-package.{bash,fish} \
-      --zsh _psc-package
+    installShellCompletion --cmd psc-package \
+      --bash <($PSC_PACKAGE --bash-completion-script $PSC_PACKAGE) \
+      --fish <($PSC_PACKAGE --fish-completion-script $PSC_PACKAGE) \
+      --zsh <($PSC_PACKAGE --zsh-completion-script $PSC_PACKAGE)
   '';
 
   meta = with lib; {
diff --git a/pkgs/development/compilers/rust/1_46.nix b/pkgs/development/compilers/rust/1_47.nix
index c999b346ee6f..e5cbae193bf1 100644
--- a/pkgs/development/compilers/rust/1_46.nix
+++ b/pkgs/development/compilers/rust/1_47.nix
@@ -19,24 +19,24 @@
 } @ args:
 
 import ./default.nix {
-  rustcVersion = "1.46.0";
-  rustcSha256 = "0a17jby2pd050s24cy4dfc0gzvgcl585v3vvyfilniyvjrqknsid";
+  rustcVersion = "1.47.0";
+  rustcSha256 = "sha256-MYXfBkxHR/LIubuMRGjt1Y/0rW0HiAyHmsGxc7do2B0=";
 
   # Note: the version MUST be one version prior to the version we're
   # building
-  bootstrapVersion = "1.45.2";
+  bootstrapVersion = "1.46.0";
 
   # fetch hashes by running `print-hashes.sh 1.45.2`
   bootstrapHashes = {
-    i686-unknown-linux-gnu = "5b2050dde23152750de89f7e59acaab6bf088d0beb5854c69c9a545fd254b936";
-    x86_64-unknown-linux-gnu = "860feed955726a4d96ffe40758a110053326b9ae11c9e1ee059e9c6222f25643";
-    arm-unknown-linux-gnueabihf = "ddb5f59bbdef84e0b7c83049461e003ed031dd881a4622365c3d475102535c60";
-    armv7-unknown-linux-gnueabihf = "7a556581f87602705f9c89b04cce621cfbba9050b6fbe478166e91d164567531";
-    aarch64-unknown-linux-gnu = "151fad66442d28a4e4786753d1afb559c4a3d359081c64769273a31c2f0f4d30";
-    x86_64-apple-darwin = "6e8067624ede10aa23081d62e0086c6f42f7228cc0d00fb5ff24d4dac65249d6";
+    i686-unknown-linux-gnu = "6ebd7e04dc18a36d08b9731cdb42d5caf8460e1eb41b75f3a8596c39f5e71206";
+    x86_64-unknown-linux-gnu = "e3b98bc3440fe92817881933f9564389eccb396f5f431f33d48b979fa2fbdcf5";
+    arm-unknown-linux-gnueabihf = "bb8af68565321f54608e918597083eb016ed0f9f4f3cc23f7cc5f467b934ce7f";
+    armv7-unknown-linux-gnueabihf = "7c0640879d7f2c38db60352e3c0f09e3fc6fa3bac6ca8f22cbccb1eb5e950121";
+    aarch64-unknown-linux-gnu = "f0c6d630f3dedb3db69d69ed9f833aa6b472363096f5164f1068c7001ca42aeb";
+    x86_64-apple-darwin = "82d61582a3772932432a99789c3b3bd4abe6baca339e355048ca9efb9ea5b4db";
   };
 
-  selectRustPackage = pkgs: pkgs.rust_1_46;
+  selectRustPackage = pkgs: pkgs.rust_1_47;
 
   rustcPatches = [
   ];
diff --git a/pkgs/development/compilers/rust/binary.nix b/pkgs/development/compilers/rust/binary.nix
index 9ae7e51e5fef..b84e390e0b0d 100644
--- a/pkgs/development/compilers/rust/binary.nix
+++ b/pkgs/development/compilers/rust/binary.nix
@@ -1,4 +1,4 @@
-{ stdenv, makeWrapper, bash, curl, darwin
+{ stdenv, makeWrapper, bash, curl, darwin, zlib
 , version
 , src
 , platform
@@ -42,17 +42,23 @@ rec {
       ./install.sh --prefix=$out \
         --components=${installComponents}
 
-      ${optionalString (stdenv.isLinux && bootstrapping) ''
+      ${optionalString (stdenv.isLinux && bootstrapping) (''
         patchelf \
           --set-interpreter $(cat $NIX_CC/nix-support/dynamic-linker) \
           "$out/bin/rustc"
+        '' + optionalString (stdenv.lib.versionAtLeast version "1.46")
+        # rustc bootstrap needs libz starting from 1.46
+        ''
+          ln -s ${zlib}/lib/libz.so.1 $out/lib/libz.so.1
+          ln -s ${zlib}/lib/libz.so $out/lib/libz.so
+        '' + ''
         patchelf \
           --set-interpreter $(cat $NIX_CC/nix-support/dynamic-linker) \
           "$out/bin/rustdoc"
         patchelf \
           --set-interpreter $(cat $NIX_CC/nix-support/dynamic-linker) \
           "$out/bin/cargo"
-      ''}
+      '')}
 
       # Do NOT, I repeat, DO NOT use `wrapProgram` on $out/bin/rustc
       # (or similar) here. It causes strange effects where rustc loads
diff --git a/pkgs/development/interpreters/ruby/rubygems/default.nix b/pkgs/development/interpreters/ruby/rubygems/default.nix
index 0bbcadba3f51..8263a987d639 100644
--- a/pkgs/development/interpreters/ruby/rubygems/default.nix
+++ b/pkgs/development/interpreters/ruby/rubygems/default.nix
@@ -2,11 +2,11 @@
 
 stdenv.mkDerivation rec {
   name = "rubygems";
-  version = "3.1.2";
+  version = "3.1.3";
 
   src = fetchurl {
     url = "https://rubygems.org/rubygems/rubygems-${version}.tgz";
-    sha256 = "0h7ij4jpj8rgnpkl63cwh2lnav73pw5wpfqra3va7077lsyadlgd";
+    sha256 = "181wjclxnq5lrwnr53famy9pg8911hi9w2v0vy7dqgjqnc4iy1hp";