From a9a359d54239c117ae46d89aa59ad6f64be986a2 Mon Sep 17 00:00:00 2001
From: Matthijs Kooijman <matthijs@stdin.nl>
Date: Tue, 6 Mar 2018 07:33:22 +0100
Subject: [PATCH] Add pre-exists state to __file (#641)

This allows checking whether a file exists, but erroring out instead of
creating the file if it does not (or is not a regular file).
---
 cdist/conf/type/__file/gencode-local  | 14 ++++++++++++++
 cdist/conf/type/__file/gencode-remote |  2 +-
 cdist/conf/type/__file/man.rst        |  9 +++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/cdist/conf/type/__file/gencode-local b/cdist/conf/type/__file/gencode-local
index aec4e43e..15a9ee0e 100755
--- a/cdist/conf/type/__file/gencode-local
+++ b/cdist/conf/type/__file/gencode-local
@@ -25,6 +25,20 @@ type="$(cat "$__object/explorer/type")"
 
 [ "$state_should" = "exists" -a "$type" = "file" ] && exit 0 # nothing to do
 
+if [ "$state_should" = "pre-exists" ]; then
+   if [ -f "$__object/parameter/source" ]; then
+      echo "--source cannot be used with --state pre-exists"
+      exit 1
+   fi
+
+   if [ "$type" = "file" ]; then
+      exit 0 # nothing to do
+   else
+      echo "File \"$destination\" does not exist"
+      exit 1
+   fi
+fi
+
 upload_file=
 create_file=
 if [ "$state_should" = "present" -o "$state_should" = "exists" ]; then
diff --git a/cdist/conf/type/__file/gencode-remote b/cdist/conf/type/__file/gencode-remote
index fe1e2212..c90be0be 100755
--- a/cdist/conf/type/__file/gencode-remote
+++ b/cdist/conf/type/__file/gencode-remote
@@ -59,7 +59,7 @@ set_mode() {
 
 set_attributes=
 case "$state_should" in
-    present|exists)
+    present|exists|pre-exists)
     # Note: Mode - needs to happen last as a chown/chgrp can alter mode by
     #  clearing S_ISUID and S_ISGID bits (see chown(2))
     for attribute in group owner mode; do
diff --git a/cdist/conf/type/__file/man.rst b/cdist/conf/type/__file/man.rst
index 7d9b413b..d06fc275 100644
--- a/cdist/conf/type/__file/man.rst
+++ b/cdist/conf/type/__file/man.rst
@@ -23,6 +23,10 @@ symlink
 directory
   replace it with the source file
 
+One exception is that when state is pre-exists, an error is raised if
+the file would have been created otherwise (e.g. it is not present or
+not a regular file).
+
 In any case, make sure that the file attributes are as specified.
 
 
@@ -41,6 +45,9 @@ state
       the file does not exist
    exists
       the file from source but only if it doesn't already exist
+   pre-exists
+      check that the file exists and is a regular file, but do not
+      create or modify it
 
 group
    Group to chgrp to.
@@ -93,6 +100,8 @@ EXAMPLES
     __file /home/frodo/.bashrc --source "/etc/skel/.bashrc" \
        --state exists \
        --owner frodo --mode 0600
+    # Check that the file is present, show an error when it is not
+    __file /etc/somefile --state pre-exists
     # Take file content from stdin
     __file /tmp/whatever --owner root --group root --mode 644 --source - << DONE
         Here goes the content for /tmp/whatever