Verification function checks if file exists

Until now, if the file to be verified didn't exist, a different checksum
would be generated, and it would stop, but it wasn't immediately clear if
the differing checksum is because the file doesn't exist at all!

With this commit, before calculating the checksum, we first make sure if
the file exists. If it doesn't exist an explicit error is printed and thus
will help the project editor to find the cause of the problem.

2 files changed, 20 insertions, 8 deletions

diff --git a/README-hacking.md b/README-hacking.md
index ec6bf4e..6cd6f46 100644
--- a/README-hacking.md
+++ b/README-hacking.md
@@ -810,11 +810,13 @@ Other basic customizations
      `reproduce/analysis/make/verify.mk`. The verification of all the files
      is only done in one recipe. First the files that go into the
      plots/figures are checked, then the LaTeX macros. Validation of the
-     former (inputs to plots/figures) should be done manually. You can see
-     two examples of the dummy steps (with `delete-me`). For the latter,
-     you just have to update the checksums. The important thing to consider
-     is that a simple checksum can be problematic because some file
-     generators print their run-time date in the file (for example as
+     former (inputs to plots/figures) should be done manually. If its the
+     first time you are doing this, you can see two examples of the dummy
+     steps (with `delete-me`, you can use them if you like). These two
+     examples should be removed before you can run the project. For the
+     latter, you just have to update the checksums. The important thing to
+     consider is that a simple checksum can be problematic because some
+     file generators print their run-time date in the file (for example as
      commented lines in a text table). When checking text files, this
      Makefile already has this function:
      `verify-txt-no-comments-leading-space`. As the name suggests, it will
diff --git a/reproduce/analysis/make/verify.mk b/reproduce/analysis/make/verify.mk
index 440ac57..1173f2c 100644
--- a/reproduce/analysis/make/verify.mk
+++ b/reproduce/analysis/make/verify.mk
@@ -23,6 +23,12 @@
 # ----------------------
 #
 # These functions are used by the final rule in this Makefil
+verify-print-error-start = \
+  echo; \
+  echo "VERIFICATION ERROR"; \
+  echo "------------------"; \
+  echo
+
 verify-print-tips = \
   echo "If you are still developing your project, you can disable"; \
   echo "verification by removing the value of the variable in the"; \
@@ -37,6 +43,12 @@ verify-print-tips = \
 verify-txt-no-comments-leading-space = \
   infile=$(strip $(1)); \
   inchecksum=$(strip $(2)); \
+  if ! [ -f "$$infile" ]; then \
+    $(call verify-print-error-start); \
+    echo "The following file (that should be verified) doesn't exist:"; \
+    echo "    $$infile"; \
+    echo; exit 1; \
+  fi; \
   checksum=$$(sed -e 's/^[[:space:]]*//g' \
                   -e 's/\#.*$$//' \
                   -e '/^$$/d' $$infile \
@@ -45,9 +57,7 @@ verify-txt-no-comments-leading-space = \
   if [ x"$$inchecksum" = x"$$checksum" ]; then \
     echo "Verified: $$infile"; \
   else \
-    echo; \
-    echo "VERIFICATION ERROR"; \
-    echo "------------------"; \
+    $(call verify-print-error-start); \
     $(call verify-print-tips); \
     echo; \
     echo "Checked file (without empty or commented lines):"; \