pkgs/test/nixpkgs-check-by-name/scripts: Various improvements

- trace function, avoids littering `echo >&2` all throughout
- Avoid `eval`, remove unneeded shellcheck

Co-Authored-By: Victor Engmark <victor@engmark.name>

pkgs/test/nixpkgs-check-by-name/scripts/fetch-tool.sh

@@ -2,18 +2,20 @@
 # Fetches the prebuilt nixpkgs-check-by-name to use from
 # the NixOS channel corresponding to the given base branch
 
-set -euo pipefail
+set -o pipefail -o errexit -o nounset
+
+trace() { echo >&2 "$@"; }
 
 if (( $# < 2 )); then
-    echo >&2 "Usage: $0 BASE_BRANCH OUTPUT_PATH"
-    echo >&2 "BASE_BRANCH: The base branch to use, e.g. master or release-23.11"
-    echo >&2 "OUTPUT_PATH: The output symlink path for the tool"
+    trace "Usage: $0 BASE_BRANCH OUTPUT_PATH"
+    trace "BASE_BRANCH: The base branch to use, e.g. master or release-23.11"
+    trace "OUTPUT_PATH: The output symlink path for the tool"
     exit 1
 fi
 baseBranch=$1
 output=$2
 
-echo >&2 -n "Determining the channel to use for PR base branch $baseBranch.. "
+trace -n "Determining the channel to use for PR base branch $baseBranch.. "
 if [[ "$baseBranch" =~ ^(release|staging|staging-next)-([0-9][0-9]\.[0-9][0-9])$ ]]; then
   # Use the release channel for all PRs to release-XX.YY, staging-XX.YY and staging-next-XX.YY
   preferredChannel=nixos-${BASH_REMATCH[2]}
@@ -25,21 +27,21 @@ fi
 # Check that the channel exists. It doesn't exist for fresh release branches
 if curl -fSs "https://channels.nixos.org/$preferredChannel"; then
     channel=$preferredChannel
-    echo >&2 "$channel"
+    trace "$channel"
 else
     # Fall back to nixos-unstable, makes sense for fresh release branches
     channel=nixos-unstable
-    echo >&2 -e "\e[33mWarning: Preferred channel $preferredChannel could not be fetched, using fallback: $channel\e[0m"
+    trace -e "\e[33mWarning: Preferred channel $preferredChannel could not be fetched, using fallback: $channel\e[0m"
 fi
 
-echo >&2 -n "Fetching latest version of channel $channel.. "
+trace -n "Fetching latest version of channel $channel.. "
 # This is probably the easiest way to get Nix to output the path to a downloaded channel!
 nixpkgs=$(nix-instantiate --find-file nixpkgs -I nixpkgs=channel:"$channel")
-echo >&2 "$nixpkgs"
+trace "$nixpkgs"
 
 # This file only exists in channels
-echo >&2 -e "Git revision of channel $channel is \e[34m$(<"$nixpkgs/.git-revision")\e[0m"
+trace -e "Git revision of channel $channel is \e[34m$(<"$nixpkgs/.git-revision")\e[0m"
 
-echo >&2 -n "Fetching the prebuilt version of nixpkgs-check-by-name.. "
+trace -n "Fetching the prebuilt version of nixpkgs-check-by-name.. "
 nix-build -o "$output" "$nixpkgs" -A tests.nixpkgs-check-by-name -j 0 >/dev/null
-realpath >&2 "$output"
+realpath "$output" >&2

pkgs/test/nixpkgs-check-by-name/scripts/run-local.sh

@@ -1,21 +1,25 @@
 #!/usr/bin/env bash
-# shellcheck disable=SC2016
 
-set -euo pipefail
+set -o pipefail -o errexit -o nounset
 
-cleanup_commands=()
+trace() { echo >&2 "$@"; }
+
+tmp=$(mktemp -d)
 cleanup() {
-    echo -n >&2 "Cleaning up.. "
-    # Run all cleanup commands in inverse order
-    for (( i=${#cleanup_commands[@]}-1; i>=0; i-- )); do
-        eval "${cleanup_commands[i]}"
-    done
-    echo >&2 "Done"
+    # Don't exit early if anything fails to cleanup
+    set +o errexit
+
+    trace -n "Cleaning up.. "
+
+    [[ -e "$tmp/base" ]] && git worktree remove --force "$tmp/base"
+    [[ -e "$tmp/merged" ]] && git worktree remove --force "$tmp/merged"
+
+    rm -rf "$tmp"
+
+    trace "Done"
 }
 trap cleanup exit
 
-tmp=$(mktemp -d)
-cleanup_commands+=('rmdir "$tmp"')
 
 repo=https://github.com/NixOS/nixpkgs.git
 
@@ -23,9 +27,9 @@ if (( $# != 0 )); then
     baseBranch=$1
     shift
 else
-    echo >&2 "Usage: $0 BASE_BRANCH [REPOSITORY]"
-    echo >&2 "BASE_BRANCH: The base branch to use, e.g. master or release-23.11"
-    echo >&2 "REPOSITORY: The repository to fetch the base branch from, defaults to $repo"
+    trace "Usage: $0 BASE_BRANCH [REPOSITORY]"
+    trace "BASE_BRANCH: The base branch to use, e.g. master or release-23.11"
+    trace "REPOSITORY: The repository to fetch the base branch from, defaults to $repo"
     exit 1
 fi
 
@@ -35,32 +39,29 @@ if (( $# != 0 )); then
 fi
 
 if [[ -n "$(git status --porcelain)" ]]; then
-    echo >&2 -e "\e[33mWarning: Dirty tree, uncommitted changes won't be taken into account\e[0m"
+    trace -e "\e[33mWarning: Dirty tree, uncommitted changes won't be taken into account\e[0m"
 fi
 headSha=$(git rev-parse HEAD)
-echo >&2 -e "Using HEAD commit \e[34m$headSha\e[0m"
+trace -e "Using HEAD commit \e[34m$headSha\e[0m"
 
-echo >&2 -n "Creating Git worktree for the HEAD commit in $tmp/merged.. "
+trace -n "Creating Git worktree for the HEAD commit in $tmp/merged.. "
 git worktree add --detach -q "$tmp/merged" HEAD
-cleanup_commands+=('git worktree remove --force "$tmp/merged"')
-echo >&2 "Done"
+trace "Done"
 
-echo >&2 -n "Fetching base branch $baseBranch to compare against.. "
+trace -n "Fetching base branch $baseBranch to compare against.. "
 git fetch -q "$repo" refs/heads/"$baseBranch"
 baseSha=$(git rev-parse FETCH_HEAD)
-echo >&2 -e "\e[34m$baseSha\e[0m"
+trace -e "\e[34m$baseSha\e[0m"
 
-echo >&2 -n "Creating Git worktree for the base branch in $tmp/base.. "
+trace -n "Creating Git worktree for the base branch in $tmp/base.. "
 git worktree add -q "$tmp/base" "$baseSha"
-cleanup_commands+=('git worktree remove --force "$tmp/base"')
-echo >&2 "Done"
+trace "Done"
 
-echo >&2 -n "Merging base branch into the HEAD commit in $tmp/merged.. "
+trace -n "Merging base branch into the HEAD commit in $tmp/merged.. "
 git -C "$tmp/merged" merge -q --no-edit "$baseSha"
-echo >&2 -e "\e[34m$(git -C "$tmp/merged" rev-parse HEAD)\e[0m"
+trace -e "\e[34m$(git -C "$tmp/merged" rev-parse HEAD)\e[0m"
 
 "$tmp/merged/pkgs/test/nixpkgs-check-by-name/scripts/fetch-tool.sh" "$baseBranch" "$tmp/tool"
-cleanup_commands+=('rm "$tmp/tool"')
 
-echo >&2 "Running nixpkgs-check-by-name.."
+trace "Running nixpkgs-check-by-name.."
 "$tmp/tool/bin/nixpkgs-check-by-name" --base "$tmp/base" "$tmp/merged"