Error out on detecting invalid header arg with missing colon

Author: kaushalmodi

src/ntangle.nim

@@ -366,6 +366,7 @@ proc getHeaderArgs(s: string): LangAndArgs =
   dbg "spaceSepParts: {spaceSepParts}"
   if spaceSepParts.len >= 3 and
      spaceSepParts[0].toLowerAscii() == "#+property:":
+    doAssert spaceSepParts[2][0] == ':'
     headerArgsRaw = spaceSepParts[2 .. spaceSepParts.high]
     let
       kwdParts = spaceSepParts[1].split(":")
@@ -375,6 +376,7 @@ proc getHeaderArgs(s: string): LangAndArgs =
   # ":header-args:", ":header-args+:", ":header-args:nim:"
   elif spaceSepParts.len >= 3 and
        spaceSepParts[0].toLowerAscii().startsWith(":header-args"):
+    doAssert spaceSepParts[1][0] == ':'
     headerArgsRaw = spaceSepParts[1 .. spaceSepParts.high]
     let
       kwdParts = spaceSepParts[0].split(":")
@@ -384,6 +386,7 @@ proc getHeaderArgs(s: string): LangAndArgs =
   elif spaceSepParts.len >= 2 and
        spaceSepParts[0].toLowerAscii() == "#+begin_src":
     if spaceSepParts.len >= 3:
+      doAssert spaceSepParts[2][0] == ':'
       headerArgsRaw = spaceSepParts[2 .. spaceSepParts.high]
     lang = spaceSepParts[1].strip()
     haType = haBeginSrc

tests/invalid_arg_no_colon/invalid_arg_no_colon.org

@@ -0,0 +1,4 @@
+Below block should not be tangled.
+#+begin_src nim tangle yes
+echo "this source block has an invalid tangle arg, no colon"
+#+end_src

tests/test.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Time-stamp: <2018-10-05 13:51:42 kmodi>
+# Time-stamp: <2018-10-07 00:27:00 kmodi>
 
 set -euo pipefail # http://redsymbol.net/articles/unofficial-bash-strict-mode
 IFS=$'\n\t'
@@ -17,6 +17,7 @@ run_test () {
     "${bin}" tests/nested_src/
 
     "${bin}" tests/missing_arg_value/missing_arg_value.org || true
+    "${bin}" tests/invalid_arg_no_colon/ || true
 
     rm -rf ./tests/foo/bar/
     "${bin}" tests/mkdirp_no/mkdirp_no.org || true

tests/wyag/write-yourself-a-git.org

@@ -1695,7 +1695,7 @@ that they come in two flavors: lightweight tags and tags objects.
 We don't even need to implement tag objects, we can reuse =GitCommit=
 and just change the =fmt= field:
 
-#+BEGIN_SRC python tangle libwyag.py
+#+BEGIN_SRC python :tangle libwyag.py
 class GitTag(GitCommit):
     fmt = b'tag'
 #+END_SRC