csvm2csv: Add some error checks

* build-aux/csvm2csv: Fail on invalid var definition.
  (expand_vars): Fail in invalid reference.
  (parseline): Fail on non-numeric range.
* build-aux/test/test-csvm2csv
  (test-fail-unknown-var-ref, test-fail-non-numeric-range)
  (test-fail-invalid-var-dfn): New tests.

build-aux/csvm2csv

@@ -46,12 +46,20 @@
 
 
 # Expand variable with its value, if any
-function expand_vars( s )
+function expand_vars( s,   value )
 {
   # attempt to parse variable (may expand into a range)
   if ( match( s, /^\$([a-zA-Z_-]+)$/, m ) )
   {
-    return vars[ m[1] ];
+    value = vars[ m[1] ];
+
+    if ( value == "" )
+    {
+      print "error: unknown variable reference: `$" m[1] "'" > "/dev/stderr"
+      exit 1
+    }
+
+    return value
   }
 
   return s
@@ -102,6 +110,12 @@ function parseline( i, m, j, me, orig )
     j  = expand_vars( m[1] )
     me = expand_vars( m[2] )
 
+    if ( !match( j, /^[0-9]+$/ ) || !match( me, /^[0-9]+$/ ) )
+    {
+      print "error: invalid range: `" $i "'" > "/dev/stderr"
+      exit 1
+    }
+
     do
     {
       $i = j
@@ -130,7 +144,12 @@ BEGIN {
 
 # lines that begin with a colon are variable definitions
 /^:/ {
-  match( $0, /^:([a-zA-Z_-]+)=(.*?)$/, m )
+  if ( !match( $0, /^:([a-zA-Z_-]+)=(.*?)$/, m ) )
+  {
+      print "error: invalid variable definition: `" $0 "'" > "/dev/stderr"
+      exit 1
+  }
+
   vars[ m[1] ] = m[2]
   next
 }

build-aux/test/test-csvm2csv

@@ -35,6 +35,8 @@ run-test()
   # SUT invocation
   declare -r given=$( ../csvm2csv < <( cat <<< "$input" ) )
 
+  test $? -eq 0 || return 1
+
   # expected output
   diff <( cat <<< "$expected" ) <( cat <<< "$given" )
 }
@@ -187,6 +189,62 @@ $baz, 5'
 }
 
 
+# :foo=0 should be considered to be defined
+test-var-zero-ref()
+{
+  declare -r input='header, line
+:foo=0
+$foo'
+
+  declare -r expected='header,line
+0'
+
+  run-test "$input" "$expected"
+}
+
+
+test-fail-unknown-var-ref()
+{
+  ((testsum++))
+
+  local -r result=$(
+    ../csvm2csv 2>&1 <<< '$undefined' \
+      && echo '(test failure: expected failure)'
+  )
+
+  grep -q 'unknown.*\$undefined' <<< "$result" \
+    || return 1
+}
+
+
+test-fail-non-numeric-range()
+{
+  ((testsum++))
+
+  local -r result=$(
+    ../csvm2csv 2>&1 <<< 'A--Z' \
+      && echo '(test failure: expected failure)'
+  )
+
+  grep -q 'invalid range.*A--Z' <<< "$result" \
+    || return 1
+}
+
+
+test-fail-invalid-var-dfn()
+{
+  ((testsum++))
+
+  local -r result=$(
+    ../csvm2csv 2>&1 <<< ':BAD@#=var' \
+      && echo '(test failure: expected failure)'
+  )
+
+  grep -q 'invalid variable definition.*:BAD@#=var' <<< "$result" \
+    || return 1
+}
+
+
 test-comment \
   && test-range \
   && test-delim \
@@ -195,13 +253,17 @@ test-comment \
   && test-var-in-range-delim \
   && test-var-with-range-delim \
   && test-var-with-var \
+  && test-var-zero-ref \
+  && test-fail-unknown-var-ref \
+  && test-fail-non-numeric-range \
+  && test-fail-invalid-var-dfn \
   || {
     echo 'csvm2csv test failed' >&2
     exit 1
   }
 
 # safety check
-test "$testsum" -eq 8 || {
+test "$testsum" -eq 12 || {
   echo 'error: did not run all csvm2csv tests!' >&2
   exit 1
 }