From c8c9618a73f383f405364b352558db3158969f88 Mon Sep 17 00:00:00 2001
From: Dave Hinton <dave.hinton1@nhs.net>
Date: Mon, 8 Sep 2025 08:34:55 +0100
Subject: [PATCH 1/7] reinvoke script to run tool

---
 scripts/githooks/check-file-format.sh | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/scripts/githooks/check-file-format.sh b/scripts/githooks/check-file-format.sh
index d7c94747..868d7d53 100755
--- a/scripts/githooks/check-file-format.sh
+++ b/scripts/githooks/check-file-format.sh
@@ -41,6 +41,14 @@ set -euo pipefail
 # ==============================================================================
 
 function main() {
+  if [[ ${#@} != 0 ]] && declare -f "main-tool-wrapper$1" >/dev/null 2>&1 ; then
+    "main-tool-wrapper$1" "${@:2}"
+  else
+    main-invocation "$@"
+  fi
+}
+
+function main-invocation() {
 
   cd "$(git rev-parse --show-toplevel)"
 
@@ -67,9 +75,9 @@ function main() {
   esac
 
   if command -v editorconfig > /dev/null 2>&1 && ! is-arg-true "${FORCE_USE_DOCKER:-false}"; then
-    filter="$filter" dry_run_opt="${dry_run_opt:-}" run-editorconfig-natively
+    filter="$filter" dry_run_opt="${dry_run_opt:-}" scripts/githooks/check-file-format.sh --natively
   else
-    filter="$filter" dry_run_opt="${dry_run_opt:-}" run-editorconfig-in-docker
+    filter="$filter" dry_run_opt="${dry_run_opt:-}" scripts/githooks/check-file-format.sh --via-docker
   fi
 }
 
@@ -77,7 +85,7 @@ function main() {
 # Arguments (provided as environment variables):
 #   dry_run_opt=[dry run option]
 #   filter=[git command to filter the files to check]
-function run-editorconfig-natively() {
+function main-tool-wrapper--natively() {
 
   # shellcheck disable=SC2046,SC2086
   editorconfig \
@@ -88,7 +96,7 @@ function run-editorconfig-natively() {
 # Arguments (provided as environment variables):
 #   dry_run_opt=[dry run option]
 #   filter=[git command to filter the files to check]
-function run-editorconfig-in-docker() {
+function main-tool-wrapper--via-docker() {
 
   # shellcheck disable=SC1091
   source ./scripts/docker/docker.lib.sh

From c1a37511556229b5ec8b14def16fa1540a6b6afe Mon Sep 17 00:00:00 2001
From: Dave Hinton <dave.hinton1@nhs.net>
Date: Mon, 8 Sep 2025 08:43:17 +0100
Subject: [PATCH 2/7] factor out call to tool

---
 scripts/githooks/check-file-format.sh | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/scripts/githooks/check-file-format.sh b/scripts/githooks/check-file-format.sh
index 868d7d53..24ca2406 100755
--- a/scripts/githooks/check-file-format.sh
+++ b/scripts/githooks/check-file-format.sh
@@ -75,10 +75,12 @@ function main-invocation() {
   esac
 
   if command -v editorconfig > /dev/null 2>&1 && ! is-arg-true "${FORCE_USE_DOCKER:-false}"; then
-    filter="$filter" dry_run_opt="${dry_run_opt:-}" scripts/githooks/check-file-format.sh --natively
+    method=--natively
   else
-    filter="$filter" dry_run_opt="${dry_run_opt:-}" scripts/githooks/check-file-format.sh --via-docker
+    method=--via-docker
   fi
+
+  filter="$filter" dry_run_opt="${dry_run_opt:-}" scripts/githooks/check-file-format.sh "$method"
 }
 
 # Run editorconfig natively.

From 77c82e0349fbb574db6e601e54970106cf7e2a0a Mon Sep 17 00:00:00 2001
From: Dave Hinton <dave.hinton1@nhs.net>
Date: Mon, 8 Sep 2025 08:59:17 +0100
Subject: [PATCH 3/7] provide list of files directly to main-tool-wrapper--*,
 instead of command to provide list

---
 scripts/githooks/check-file-format.sh | 48 +++++++++++++++------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/scripts/githooks/check-file-format.sh b/scripts/githooks/check-file-format.sh
index 24ca2406..d1f5c3eb 100755
--- a/scripts/githooks/check-file-format.sh
+++ b/scripts/githooks/check-file-format.sh
@@ -56,23 +56,9 @@ function main-invocation() {
   is-arg-true "${dry_run:-false}" && dry_run_opt="--dry-run"
 
   check=${check:-working-tree-changes}
-  case $check in
-    "all")
-      filter="git ls-files"
-      ;;
-    "staged-changes")
-      filter="git diff --diff-filter=ACMRT --name-only --cached"
-      ;;
-    "working-tree-changes")
-      filter="git diff --diff-filter=ACMRT --name-only"
-      ;;
-    "branch")
-      filter="git diff --diff-filter=ACMRT --name-only ${BRANCH_NAME:-origin/main}"
-      ;;
-    *)
-      echo "Unrecognised check mode: $check" >&2 && exit 1
-      ;;
-  esac
+  if ! declare -f "list-files-to-check--$check" >/dev/null 2>&1 ; then
+    echo "Unrecognised check mode: $check" >&2 && exit 1
+  fi
 
   if command -v editorconfig > /dev/null 2>&1 && ! is-arg-true "${FORCE_USE_DOCKER:-false}"; then
     method=--natively
@@ -80,24 +66,24 @@ function main-invocation() {
     method=--via-docker
   fi
 
-  filter="$filter" dry_run_opt="${dry_run_opt:-}" scripts/githooks/check-file-format.sh "$method"
+  dry_run_opt="${dry_run_opt:-}" scripts/githooks/check-file-format.sh "$method" $(list-files-to-check--"$check")
 }
 
 # Run editorconfig natively.
 # Arguments (provided as environment variables):
 #   dry_run_opt=[dry run option]
-#   filter=[git command to filter the files to check]
+# Arguments (provided as positional parameters): files to check
 function main-tool-wrapper--natively() {
 
   # shellcheck disable=SC2046,SC2086
   editorconfig \
-    --exclude '.git/' $dry_run_opt $($filter)
+    --exclude '.git/' $dry_run_opt "$@"
 }
 
 # Run editorconfig in a Docker container.
 # Arguments (provided as environment variables):
 #   dry_run_opt=[dry run option]
-#   filter=[git command to filter the files to check]
+# Arguments (provided as positional parameters): files to check
 function main-tool-wrapper--via-docker() {
 
   # shellcheck disable=SC1091
@@ -111,7 +97,25 @@ function main-tool-wrapper--via-docker() {
   docker run --rm --platform linux/amd64 \
     --volume "$PWD":/check \
     "$image" \
-      sh -c "ec --exclude '.git/' $dry_run_opt \$($filter) /dev/null"
+      sh -c "ec --exclude '.git/' $dry_run_opt $(printf '%q ' "$@") /dev/null"
+}
+
+# ==============================================================================
+
+function list-files-to-check--all() {
+  git ls-files
+}
+
+function list-files-to-check--staged-changes() {
+  git diff --diff-filter=ACMRT --name-only --cached
+}
+
+function list-files-to-check--working-tree-changes() {
+  git diff --diff-filter=ACMRT --name-only
+}
+
+function list-files-to-check--branch() {
+  git diff --diff-filter=ACMRT --name-only ${BRANCH_NAME:-origin/main}
 }
 
 # ==============================================================================

From 84cfdc10f6bdccae9c6e68c5c60236acd609d491 Mon Sep 17 00:00:00 2001
From: Dave Hinton <dave.hinton1@nhs.net>
Date: Mon, 8 Sep 2025 09:05:18 +0100
Subject: [PATCH 4/7] split files into batches

---
 scripts/githooks/check-file-format.sh | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/scripts/githooks/check-file-format.sh b/scripts/githooks/check-file-format.sh
index d1f5c3eb..1cf26a34 100755
--- a/scripts/githooks/check-file-format.sh
+++ b/scripts/githooks/check-file-format.sh
@@ -66,7 +66,12 @@ function main-invocation() {
     method=--via-docker
   fi
 
-  dry_run_opt="${dry_run_opt:-}" scripts/githooks/check-file-format.sh "$method" $(list-files-to-check--"$check")
+  list-files-to-check--"$check" |
+  # Maximum size of command line and environment combined is typically
+  # 2MB on Linux but only 256KB on macOS. Assume a maximum filename
+  # length of 200 characters and limiting us to batches of 1000 files
+  # gives us a bit of a safety margin.
+  dry_run_opt="${dry_run_opt:-}" xargs --max-args=1000 scripts/githooks/check-file-format.sh "$method"
 }
 
 # Run editorconfig natively.

From 18e19ba5b5bce98e3c6631448685dd57311a3da9 Mon Sep 17 00:00:00 2001
From: Dave Hinton <dave.hinton1@nhs.net>
Date: Mon, 8 Sep 2025 09:06:56 +0100
Subject: [PATCH 5/7] use --no-run-if-empty to avoid empty batches

---
 scripts/githooks/check-file-format.sh | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/scripts/githooks/check-file-format.sh b/scripts/githooks/check-file-format.sh
index 1cf26a34..e99f92b6 100755
--- a/scripts/githooks/check-file-format.sh
+++ b/scripts/githooks/check-file-format.sh
@@ -71,7 +71,7 @@ function main-invocation() {
   # 2MB on Linux but only 256KB on macOS. Assume a maximum filename
   # length of 200 characters and limiting us to batches of 1000 files
   # gives us a bit of a safety margin.
-  dry_run_opt="${dry_run_opt:-}" xargs --max-args=1000 scripts/githooks/check-file-format.sh "$method"
+  dry_run_opt="${dry_run_opt:-}" xargs --max-args=1000 --no-run-if-empty scripts/githooks/check-file-format.sh "$method"
 }
 
 # Run editorconfig natively.
@@ -96,13 +96,10 @@ function main-tool-wrapper--via-docker() {
 
   # shellcheck disable=SC2155
   local image=$(name=mstruebing/editorconfig-checker docker-get-image-version-and-pull)
-  # We use /dev/null here as a backstop in case there are no files in the state
-  # we choose. If the filter comes back empty, adding `/dev/null` onto it has
-  # the effect of preventing `ec` from treating "no files" as "all the files".
   docker run --rm --platform linux/amd64 \
     --volume "$PWD":/check \
     "$image" \
-      sh -c "ec --exclude '.git/' $dry_run_opt $(printf '%q ' "$@") /dev/null"
+      sh -c "ec --exclude '.git/' $dry_run_opt $(printf '%q ' "$@")"
 }
 
 # ==============================================================================

From 1c9b277e5bf3a4785e53542f2a86c82ec3f58196 Mon Sep 17 00:00:00 2001
From: Dave Hinton <dave.hinton1@nhs.net>
Date: Mon, 8 Sep 2025 09:09:27 +0100
Subject: [PATCH 6/7] terminate filenames with NUL, not LF

---
 scripts/githooks/check-file-format.sh | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/scripts/githooks/check-file-format.sh b/scripts/githooks/check-file-format.sh
index e99f92b6..021acad9 100755
--- a/scripts/githooks/check-file-format.sh
+++ b/scripts/githooks/check-file-format.sh
@@ -71,7 +71,7 @@ function main-invocation() {
   # 2MB on Linux but only 256KB on macOS. Assume a maximum filename
   # length of 200 characters and limiting us to batches of 1000 files
   # gives us a bit of a safety margin.
-  dry_run_opt="${dry_run_opt:-}" xargs --max-args=1000 --no-run-if-empty scripts/githooks/check-file-format.sh "$method"
+  dry_run_opt="${dry_run_opt:-}" xargs -0 --max-args=1000 --no-run-if-empty scripts/githooks/check-file-format.sh "$method"
 }
 
 # Run editorconfig natively.
@@ -104,20 +104,23 @@ function main-tool-wrapper--via-docker() {
 
 # ==============================================================================
 
+# These all produce filenames terminated by a NUL character, so that we
+# can handle filenames that contain spaces.
+
 function list-files-to-check--all() {
-  git ls-files
+  git ls-files -z
 }
 
 function list-files-to-check--staged-changes() {
-  git diff --diff-filter=ACMRT --name-only --cached
+  git diff -z --diff-filter=ACMRT --name-only --cached
 }
 
 function list-files-to-check--working-tree-changes() {
-  git diff --diff-filter=ACMRT --name-only
+  git diff -z --diff-filter=ACMRT --name-only
 }
 
 function list-files-to-check--branch() {
-  git diff --diff-filter=ACMRT --name-only ${BRANCH_NAME:-origin/main}
+  git diff -z --diff-filter=ACMRT --name-only ${BRANCH_NAME:-origin/main}
 }
 
 # ==============================================================================

From c2c74345ebc873dd2ac523774ce36aef4ab25a74 Mon Sep 17 00:00:00 2001
From: Dave Hinton <dave.hinton1@nhs.net>
Date: Mon, 8 Sep 2025 09:16:50 +0100
Subject: [PATCH 7/7] rename functions

---
 scripts/githooks/check-file-format.sh | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/scripts/githooks/check-file-format.sh b/scripts/githooks/check-file-format.sh
index 021acad9..8ea0c142 100755
--- a/scripts/githooks/check-file-format.sh
+++ b/scripts/githooks/check-file-format.sh
@@ -41,8 +41,8 @@ set -euo pipefail
 # ==============================================================================
 
 function main() {
-  if [[ ${#@} != 0 ]] && declare -f "main-tool-wrapper$1" >/dev/null 2>&1 ; then
-    "main-tool-wrapper$1" "${@:2}"
+  if [[ ${#@} != 0 ]] && declare -f "run-editorconfig$1" >/dev/null 2>&1 ; then
+    "run-editorconfig$1" "${@:2}"
   else
     main-invocation "$@"
   fi
@@ -78,7 +78,7 @@ function main-invocation() {
 # Arguments (provided as environment variables):
 #   dry_run_opt=[dry run option]
 # Arguments (provided as positional parameters): files to check
-function main-tool-wrapper--natively() {
+function run-editorconfig--natively() {
 
   # shellcheck disable=SC2046,SC2086
   editorconfig \
@@ -89,7 +89,7 @@ function main-tool-wrapper--natively() {
 # Arguments (provided as environment variables):
 #   dry_run_opt=[dry run option]
 # Arguments (provided as positional parameters): files to check
-function main-tool-wrapper--via-docker() {
+function run-editorconfig--via-docker() {
 
   # shellcheck disable=SC1091
   source ./scripts/docker/docker.lib.sh