Merge #16327: scripts and tools: Update ShellCheck linter

1ac454a384 Enable ShellCheck rules (Hennadii Stepanov)

Pull request description:

  Enable some simple ShellCheck rules.

  Note for reviewers: `bash` and `shellcheck` on macOS are different from ones on Ubuntu.
  For local tests the latest `shellcheck` version 0.6.0 should be used (see #15166).

ACKs for top commit:
  practicalswift:
    utACK 1ac454a384
  dongcarl:
    utACK 1ac454a
  fanquake:
    ACK 1ac454a384

Tree-SHA512: 8d0a3a5c09fe1a0c22120178f5e6b80f81f746f8c3356b7701ff301c117acb2edea8fe08f08fb54ed73f94b1617515fb239fa28e7ab4121f74872e6494b6f20e

test/lint/commit-script-check.sh

@@ -18,12 +18,12 @@ if test "x$1" = "x"; then
 fi
 
 RET=0
-PREV_BRANCH=`git name-rev --name-only HEAD`
-PREV_HEAD=`git rev-parse HEAD`
-for commit in `git rev-list --reverse $1`; do
+PREV_BRANCH=$(git name-rev --name-only HEAD)
+PREV_HEAD=$(git rev-parse HEAD)
+for commit in $(git rev-list --reverse $1); do
     if git rev-list -n 1 --pretty="%s" $commit | grep -q "^scripted-diff:"; then
         git checkout --quiet $commit^ || exit
-        SCRIPT="`git rev-list --format=%b -n1 $commit | sed '/^-BEGIN VERIFY SCRIPT-$/,/^-END VERIFY SCRIPT-$/{//!b};d'`"
+        SCRIPT="$(git rev-list --format=%b -n1 $commit | sed '/^-BEGIN VERIFY SCRIPT-$/,/^-END VERIFY SCRIPT-$/{//!b};d')"
         if test "x$SCRIPT" = "x"; then
             echo "Error: missing script for: $commit"
             echo "Failed"

test/lint/lint-circular-dependencies.sh

@@ -39,7 +39,7 @@ CIRCULAR_DEPENDENCIES=()
 
 IFS=$'\n'
 for CIRC in $(cd src && ../contrib/devtools/circular-dependencies.py {*,*/*,*/*/*}.{h,cpp} | sed -e 's/^Circular dependency: //'); do
-    CIRCULAR_DEPENDENCIES+=($CIRC)
+    CIRCULAR_DEPENDENCIES+=( "$CIRC" )
     IS_EXPECTED_CIRC=0
     for EXPECTED_CIRC in "${EXPECTED_CIRCULAR_DEPENDENCIES[@]}"; do
         if [[ "${CIRC}" == "${EXPECTED_CIRC}" ]]; then

test/lint/lint-logs.sh

@@ -19,6 +19,7 @@ UNTERMINATED_LOGS=$(git grep --extended-regexp "LogPrintf?\(" -- "*.cpp" | \
     grep -v "LogPrint()" | \
     grep -v "LogPrintf()")
 if [[ ${UNTERMINATED_LOGS} != "" ]]; then
+    # shellcheck disable=SC2028
     echo "All calls to LogPrintf() and LogPrint() should be terminated with \\n"
     echo
     echo "${UNTERMINATED_LOGS}"

test/lint/lint-shell.sh

@@ -23,25 +23,9 @@ fi
 
 # Disabled warnings:
 disabled=(
-    SC1087 # Use braces when expanding arrays, e.g. ${array[idx]} (or ${var}[.. to quiet).
-    SC2001 # See if you can use ${variable//search/replace} instead.
-    SC2004 # $/${} is unnecessary on arithmetic variables.
-    SC2005 # Useless echo? Instead of 'echo $(cmd)', just use 'cmd'.
-    SC2006 # Use $(..) instead of legacy `..`.
-    SC2016 # Expressions don't expand in single quotes, use double quotes for that.
-    SC2028 # echo won't expand escape sequences. Consider printf.
     SC2046 # Quote this to prevent word splitting.
-    SC2048 # Use "$@" (with quotes) to prevent whitespace problems.
-    SC2066 # Since you double quoted this, it will not word split, and the loop will only run once.
     SC2086 # Double quote to prevent globbing and word splitting.
-    SC2116 # Useless echo? Instead of 'cmd $(echo foo)', just use 'cmd foo'.
     SC2162 # read without -r will mangle backslashes.
-    SC2166 # Prefer [ p ] {&&,||} [ q ] as [ p -{a,o} q ] is not well defined.
-    SC2181 # Check exit code directly with e.g. 'if mycmd;', not indirectly with $?.
-    SC2206 # Quote to prevent word splitting, or split robustly with mapfile or read -a.
-    SC2207 # Prefer mapfile or read -a to split command output (or quote to avoid splitting).
-    SC2230 # which is non-standard. Use builtin 'command -v' instead.
-    SC2236 # Don't force -n instead of ! -z.
 )
 shellcheck -e "$(IFS=","; echo "${disabled[*]}")" \
     $(git ls-files -- "*.sh" | grep -vE 'src/(secp256k1|univalue)/')