fix refreshing git-hooks when using git-bash

real symlinks require admin-rights or developer mode, and the other
fallback mechanisms won't work for the version of git that comes with
git-bash. Either spawning the process failes or worse it silently fails
and basically ignores the hook.
MSYS uses regular file copy when using "ln -s" which means to make sure
the current version of a hook is used the hooks need to replaced
everytime or the file contents need to be compared. When using hardlinks
instead it is enough to check whether the source and target share the
same inode.

Change-Id: Ib2e325048779828313afc7fc9d120661d55fc3a5
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/177498
Reviewed-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>
Tested-by: Jenkins

g

@@ -29,9 +29,23 @@ usage()
     echo " -z restore the git hooks and do other sanity checks"
 }
 
+refresh_create_link()
+{
+    local hook_name=$1
+    local hook=$2
+    local lnarg=$3
+
+    # if it doesn't exist or is neither a symlink nor sharing the same inode (hardlink)
+    if [ ! -e "${hook?}" ] || [ ! \( -L "${hook?}" -o "${hook_name}" -ef "${hook?}" \) ] ; then
+        rm -f "${hook?}"
+        ln -f $lnarg "${hook_name}" "${hook?}"
+    fi
+}
+
 refresh_submodule_hooks()
 {
     local repo=$1
+    local lnarg=$2
     local hook
     local hook_name
 
@@ -42,10 +56,7 @@ refresh_submodule_hooks()
                 continue
             fi
             hook="${repo?}/.git/hooks/${hook_name##*/}"
-            if [ ! -e "${hook?}" ] || [ ! -L "${hook?}" ] ; then
+            refresh_create_link "${hook_name}" "${hook?}" "$lnarg"
-                rm -f "${hook?}"
-                ln -sf "${hook_name}" "${hook?}"
-            fi
         done
         # override if need be by the submodules' own hooks
         for hook_name in "${COREDIR?}/${repo?}/.git-hooks"/* ; do
@@ -53,10 +64,7 @@ refresh_submodule_hooks()
                 continue
             fi
             hook="${repo?}/.git/hooks/${hook_name##*/}"
-            if [ ! -e "${hook?}" ] || [ ! -L "${hook?}" ] ; then
+            refresh_create_link "${hook_name}" "${hook?}" "$lnarg"
-                rm -f "${hook?}"
-                ln -sf "${hook_name}" "${hook?}"
-            fi
         done
     elif [ -d .git/modules/"${repo}"/hooks ] ; then
         for hook_name in "${COREDIR?}/.git-hooks"/* ; do
@@ -64,10 +72,7 @@ refresh_submodule_hooks()
                 continue
             fi
             hook=".git/modules/${repo?}/hooks/${hook_name##*/}"
-            if [ ! -e "${hook?}" ] || [ ! -L "${hook?}" ] ; then
+            refresh_create_link "${hook_name}" "${hook?}" "$lnarg"
-                rm -f "${hook?}"
-                ln -sf "${hook_name}" "${hook?}"
-            fi
         done
         # override if need be by the submodules' own hooks
         for hook_name in "${COREDIR?}/${repo?}/.git-hooks"/* ; do
@@ -75,10 +80,7 @@ refresh_submodule_hooks()
                 continue
             fi
             hook=".git/modules/${repo?}/hooks/${hook_name##*/}"
-            if [ ! -e "${hook?}" ] || [ ! -L "${hook?}" ] ; then
+            refresh_create_link "${hook_name}" "${hook?}" "$lnarg"
-                rm -f "${hook?}"
-                ln -sf "${hook_name}" "${hook?}"
-            fi
         done
     fi
 
@@ -89,63 +91,35 @@ refresh_all_hooks()
     local repo
     local hook_name
     local hook
-    local winlnk
-    local wingit
     local gitbash
-    local lnkfile=".git/hooks/pre-commit"
+    local lnarg
 
     pushd "${COREDIR?}" > /dev/null
 
     # it is 'GIT for Windows'
-    wingit=$(git --version | grep -ic windows)
     gitbash=$(echo $OSTYPE | grep -ic msys)
 
-    # In the win-git-bash, do not make links, it makes only copies
+    # git-bash/MSYS doesn't create symlinks by default, and "real" symlinks are restricted to
-    if [ $gitbash -eq 1 ]; then
+    # Admin-mode or when devmode is activated, junction points as fallback would work for bash/
-        if [ -d ".git" ]; then
+    # regular use but not when git tries to spawn them, similar for plain windows shortcuts (worse
-            if [ ! -e "${lnkfile}" ] || [ ! -L "${lnkfile}" ] ; then
+    # because running the hooks will fail silently/they'd be inactive)
-                # here when wrong link then the file not exist
+    # ln -s without setting MSYS to contain winsymlinks:{lnk,native,nativestrict,sys} to force one
-                echo "Your hooks not right, solve this in cygwin with"
+    # of the other modes described above will do plain copies.
-                echo "   ./g -z"
+    # So in case of git-bash use hardlinks since those work just fine, everywhere else use symlinks
-            fi
+    if [ $gitbash -ne 1 ]; then
-        fi
+        lnarg="--symbolic"
-    else
-        if [ $wingit -eq 1 ]; then
-            # There's no ".git" e.g. in a secondary worktree
-            if [ -d ".git" ]; then
-                winlnk=0
-                if [ -e "${lnkfile}" ] && [ -L "${lnkfile}" ] ; then
-                    # if linux-links or windows-links?
-                    # dos dir output windows link:
-                    #   04.09.2020  10:54    <SYMLINK>      pre-commit [..\..\.git-hooks\pre-commit]
-                    # dos dir output linux link:
-                    #   file not found
-                    winlnk=$(cmd /C "DIR ${lnkfile//'/'/'\'}" 2>&1)
-                    winlnk=$(echo "$winlnk" | grep -icE "<SYMLINK>.*${lnkfile##*/} \[")
-                fi
-
-                if [ $winlnk -eq 0 ]; then
-                    echo "You using GIT for Windows, but the hook-links not right, change with mklink"
-                    cat .git-hooks/README
-                fi
-            fi
-        else
-            # There's no ".git" e.g. in a secondary worktree
-            if [ -d ".git" ]; then
-                for hook_name in "${COREDIR?}/.git-hooks"/* ; do
-                    hook=".git/hooks/${hook_name##*/}"
-                    if [ ! -e "${hook?}" ] || [ ! -L "${hook?}" ] ; then
-                        rm -f "${hook?}"
-                        ln -sf "${hook_name}" "${hook?}"
-                    fi
-                done
-            fi
-
-            for repo in ${SUBMODULES_ALL?} ; do
-                refresh_submodule_hooks "$repo"
-            done
-        fi
     fi
+    # There's no ".git" e.g. in a secondary worktree
+    if [ -d ".git" ]; then
+        for hook_name in "${COREDIR?}/.git-hooks"/* ; do
+            hook=".git/hooks/${hook_name##*/}"
+            refresh_create_link "${hook_name}" "${hook?}" "$lnarg"
+        done
+    fi
+
+    for repo in ${SUBMODULES_ALL?} ; do
+        refresh_submodule_hooks "$repo" "$lnarg"
+    done
 
     popd > /dev/null