Fixes #108.

src/nimble.nim

@@ -527,6 +527,10 @@ proc processDeps(pkginfo: PackageInfo, options: Options): seq[string] =
 
 proc buildFromDir(pkgInfo: PackageInfo, paths: seq[string], forRelease: bool) =
   ## Builds a package as specified by ``pkgInfo``.
+  if pkgInfo.bin.len == 0:
+    raise newException(NimbleError,
+        "Nothing to build. Did you specify a module to build using the" &
+        " `bin` key in your .nimble file?")
   let realDir = pkgInfo.getRealDir()
   let releaseOpt = if forRelease: "-d:release" else: ""
   var args = ""

tests/issue108/issue108.nimble

@@ -0,0 +1,11 @@
+# Package
+
+version       = "0.1.0"
+author        = "Dominik Picheta"
+description   = "Test for issue 108."
+license       = "BSD"
+
+# Dependencies
+
+requires "nim >= 0.12.1"
+

tests/tester.nim

@@ -78,6 +78,13 @@ test "issue #126":
     check exitCode1 != QuitSuccess
     check "The .nimble file name must match name specified inside it." in lines1[^1]
 
+test "issue #108":
+  cd "issue108":
+    let (output, exitCode) = execCmdEx("../" & path & " build")
+    let lines = output.strip.splitLines()
+    check exitCode != QuitSuccess
+    check "Nothing to build" in lines[^1]
+
 test "can list":
   check execCmdEx(path & " list").exitCode == QuitSuccess