Meta: Only complain about linter tools if relevant files have changed

Meta/lint-clang-format.sh

@@ -5,32 +5,6 @@ set -e
 script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
 cd "${script_path}/.." || exit 1
 
-CLANG_FORMAT=false
-if command -v clang-format-11 >/dev/null 2>&1 ; then
-    CLANG_FORMAT=clang-format-11
-elif command -v clang-format >/dev/null 2>&1 ; then
-    CLANG_FORMAT=clang-format
-    if ! "${CLANG_FORMAT}" --version | grep -qF ' 11.' ; then
-        echo "You are using '$("${CLANG_FORMAT}" --version)', which appears to not be clang-format 11."
-        echo "It is very likely that the resulting changes are not what you wanted."
-    fi
-else
-    echo "clang-format-10 is not available. Either skip this script, or install clang-format-11."
-    echo "(If you install a package 'clang-format', please make sure it's version 11.)"
-    exit 1
-fi
-
-if [ "$#" -gt "0" ] && [ "x--overwrite-inplace" = "x$1" ] ; then
-    true # The only way to run this script.
-else
-    # Note that this branch also covers --help, -h, -help, -?, etc.
-    echo "USAGE: $0 --overwrite-inplace"
-    echo "The argument is necessary to make you aware that this *will* overwrite your local files."
-    exit 1
-fi
-
-echo "Using ${CLANG_FORMAT}"
-
 if [ "$#" -eq "1" ]; then
     mapfile -t files < <(
         git ls-files -- \
@@ -55,6 +29,32 @@ else
 fi
 
 if (( ${#files[@]} )); then
+    CLANG_FORMAT=false
+    if command -v clang-format-11 >/dev/null 2>&1 ; then
+        CLANG_FORMAT=clang-format-11
+    elif command -v clang-format >/dev/null 2>&1 ; then
+        CLANG_FORMAT=clang-format
+        if ! "${CLANG_FORMAT}" --version | grep -qF ' 11.' ; then
+            echo "You are using '$("${CLANG_FORMAT}" --version)', which appears to not be clang-format 11."
+            echo "It is very likely that the resulting changes are not what you wanted."
+        fi
+    else
+        echo "clang-format-11 is not available, but C or C++ files need linting! Either skip this script, or install clang-format-11."
+        echo "(If you install a package 'clang-format', please make sure it's version 11.)"
+        exit 1
+    fi
+
+    if [ "$#" -gt "0" ] && [ "x--overwrite-inplace" = "x$1" ] ; then
+        true # The only way to run this script.
+    else
+        # Note that this branch also covers --help, -h, -help, -?, etc.
+        echo "USAGE: $0 --overwrite-inplace"
+        echo "The argument is necessary to make you aware that this *will* overwrite your local files."
+        exit 1
+    fi
+
+    echo "Using ${CLANG_FORMAT}"
+
     "${CLANG_FORMAT}" -style=file -i "${files[@]}"
     echo "Maybe some files have changed. Sorry, but clang-format doesn't indicate what happened."
 else

Meta/lint-prettier.sh

@@ -5,16 +5,6 @@ set -e
 script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
 cd "${script_path}/.." || exit 1
 
-if ! command -v prettier >/dev/null 2>&1 ; then
-    echo "prettier is not available. Either skip this script, or install prettier."
-    exit 1
-fi
-
-if ! prettier --version | grep -qF '2.' ; then
-    echo "You are using '$(prettier --version)', which appears to not be prettier 2."
-    exit 1
-fi
-
 if [ "$#" -eq "0" ]; then
     mapfile -t files < <(
         git ls-files \
@@ -32,6 +22,16 @@ else
 fi
 
 if (( ${#files[@]} )); then
+    if ! command -v prettier >/dev/null 2>&1 ; then
+        echo "prettier is not available, but JS files need linting! Either skip this script, or install prettier."
+        exit 1
+    fi
+
+    if ! prettier --version | grep -qF '2.' ; then
+        echo "You are using '$(prettier --version)', which appears to not be prettier 2."
+        exit 1
+    fi
+
     prettier --check "${files[@]}"
 else
     echo "No .js files to check."

Meta/lint-python.sh

@@ -5,11 +5,6 @@ set -e
 script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
 cd "${script_path}/.." || exit 1
 
-if ! command -v flake8 >/dev/null 2>&1 ; then
-    echo "flake8 is not available. Either skip this script, or install flake8."
-    exit 1
-fi
-
 if [ "$#" -eq "0" ]; then
     mapfile -t files < <(
         git ls-files '*.py'
@@ -24,6 +19,11 @@ else
 fi
 
 if (( ${#files[@]} )); then
+    if ! command -v flake8 >/dev/null 2>&1 ; then
+        echo "flake8 is not available, but python files need linting! Either skip this script, or install flake8."
+        exit 1
+    fi
+
     flake8 "${files[@]}" --max-line-length=120
 else
     echo "No py files to check."

Meta/lint-shell-scripts.sh

@@ -5,11 +5,6 @@ set -eo pipefail
 script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
 cd "$script_path/.."
 
-if ! command -v shellcheck &>/dev/null ; then
-    echo "shellcheck is not available. Either skip this script, or install shellcheck."
-    exit 1
-fi
-
 if [ "$#" -eq "0" ]; then
     mapfile -t files < <(
         git ls-files -- \
@@ -28,6 +23,11 @@ else
 fi
 
 if (( ${#files[@]} )); then
+    if ! command -v shellcheck &>/dev/null ; then
+        echo "shellcheck is not available, but shell files need linting! Either skip this script, or install shellcheck."
+        exit 1
+    fi
+
     shellcheck "${files[@]}"
 else
     echo "No .sh files to check."