Use docker image for custom-check scripts

NOTE: The custom-linting-rules test fails due to the following (legit)
warnings:

  ale_linters/clojure/clj_kondo.vim:29 Use snake_case names for linters
  ale_linters/elixir/elixir_ls.vim:15 Use snake_case names for linters
  ale_linters/go/golangci_lint.vim:54 Use snake_case names for linters
  ale_linters/swift/swiftformat.vim:56 Use snake_case names for linters

The message wasn't getting printed because docker was explicitly only
being asked to connect stdout (ignoring stderr). Unclear yet why the
error code wasn't getting bubbled up.

test/script/check-duplicate-tags

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+set -e
+
+grep --exclude=tags -roh '\*.*\*$' doc | sort | uniq -d

test/script/check-tag-alignment

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+exit_code=0
+
+# Documentation tags need to be aligned to the right margin, so look for
+# tags which aren't at the right margin.
+grep ' \*[^*]\+\*$' doc/ -r \
+    | awk '{ sep = index($0, ":"); if (length(substr($0, sep + 1 )) < 79) { print } }' \
+    | grep . && exit_code=1
+
+exit $exit_code

test/script/check-tag-references

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+set -e
+
+exit_code=0
+tag_regex='[gb]\?:\?\(ale\|ALE\)[a-zA-Z_\-]\+'
+
+tags="$(mktemp -t tags.XXXXXXXX)"
+refs="$(mktemp -t refs.XXXXXXXX)"
+# Grep for tags and references, and complain if we find a reference without
+# a tag for the reference. Only our tags will be included.
+grep --exclude=tags -roh "\\*$tag_regex\\*" doc | sed 's/*//g' | sort -u > "$tags"
+grep --exclude=tags -roh "|$tag_regex|" doc | sed 's/|//g' | sort -u > "$refs"
+
+exit_code=0
+
+if ! [[ $(comm -23 $refs $tags | wc -l) -eq 0 ]]; then
+  exit_code=1
+fi
+
+rm "$tags"
+rm "$refs"

test/script/custom-checks

@@ -13,7 +13,7 @@ echo 'Custom warnings/errors follow:'
 echo
 
 set -o pipefail
-docker run -a stdout "${docker_flags[@]}" test/script/custom-linting-rules . || exit_code=$?
+docker run "${docker_flags[@]}" test/script/custom-linting-rules . || exit_code=$?
 set +o pipefail
 echo
 
@@ -23,7 +23,10 @@ echo '========================================'
 echo 'Duplicate tags follow:'
 echo
 
-grep --exclude=tags -roh '\*.*\*$' doc | sort | uniq -d || exit_code=$?
+set -o pipefail
+docker run "${docker_flags[@]}" test/script/check-duplicate-tags . || exit_code=$?
+set +o pipefail
+echo
 
 echo '========================================'
 echo 'Checking for invalid tag references'
@@ -31,14 +34,9 @@ echo '========================================'
 echo 'Invalid tag references tags follow:'
 echo
 
-tag_regex='[gb]\?:\?\(ale\|ALE\)[a-zA-Z_\-]\+'
+set -o pipefail
-
+docker run "${docker_flags[@]}" test/script/check-tag-references || exit_code=$?
-# Grep for tags and references, and complain if we find a reference without
+set +o pipefail
-# a tag for the reference. Only our tags will be included.
-diff -u \
-    <(grep --exclude=tags -roh "\\*$tag_regex\\*" doc | sort -u | sed 's/*//g') \
-    <(grep --exclude=tags -roh "|$tag_regex|" doc | sort -u | sed 's/|//g') \
-    | grep '^+[^+]' && exit_code=1
 
 echo '========================================'
 echo 'diff supported-tools.md and doc/ale-supported-languages-and-tools.txt tables'
@@ -56,18 +54,18 @@ echo '========================================'
 echo 'Badly aligned tags follow:'
 echo
 
-# Documentation tags need to be aligned to the right margin, so look for
+set -o pipefail
-# tags which aren't at the right margin.
+docker run "${docker_flags[@]}" test/script/check-tag-alignment || exit_code=$?
-grep ' \*[^*]\+\*$' doc/ -r \
+set +o pipefail
-    | awk '{ sep = index($0, ":"); if (length(substr($0, sep + 1 )) < 79) { print } }' \
-    | grep . && exit_code=1
 
 echo '========================================'
 echo 'Look for table of contents issues'
 echo '========================================'
 echo
 
-test/script/check-toc || exit_code=$?
+set -o pipefail
+docker run "${docker_flags[@]}" test/script/check-toc || exit_code=$?
+set +o pipefail
 
 echo '========================================'
 echo 'Check Python code'