Change default value logic for stepCmd and cmdInput (see README).

README.md

@@ -125,7 +125,7 @@ Step definitions are JSON objects with the following keys:
   `'.'`, the project root directory)*.
 
 * `stepCmd` *(optional)*: the command to execute for this step. *(defaults to
-  `sh`)*
+  `true` unless `cmdInput` is given, in which case it defaults to `sh`)*
 
 * `cmdInput` *(optional)*: an array of string that will be concatenated with
   newlines separating each string and piped as input to the command for this

src/main/nim/strawbosspkg/configuration.nim

@@ -146,15 +146,25 @@ proc loadProjectConfig*(cfgFile: string): ProjectConfig =
     steps[sName] = Step(
       name:         sName,
       workingDir:   pJson.getIfExists("workingDir").getStr("."),
-      stepCmd:      pJson.getIfExists("stepCmd").getStr("sh"),
+      stepCmd:      pJson.getIfExists("stepCmd").getStr("NOT GIVEN"),
       depends:      pJson.getIfExists("depends").getElems.mapIt(it.getStr),
       artifacts:    pJson.getIfExists("artifacts").getElems.mapIt(it.getStr),
       cmdInput:     pJson.getIfExists("cmdInput").getElems.mapIt(it.getStr),
       expectedEnv:  pJson.getIfExists("expectedEnv").getElems.mapIt(it.getStr),
       dontSkip:     pJson.getIfExists("dontSkip").getBVal(false))
 
-    if steps[sName].stepCmd == "sh" and steps[sName].cmdInput.len == 0:
-      warn "Step " & sName & " uses 'sh' as its command but has no cmdInput."
+    # cmdInput and stepCmd are related, so we have a conditional defaulting.
+    # Four possibilities:
+
+    if steps[sName].stepCmd == "NOT GIVEN" and steps[sName].cmdInput.len == 0:
+      # 1. Neither given: default to no-op
+      steps[sName].stepCmd = "true"
+
+    if steps[sName].stepCmd == "NOT GIVEN" and steps[sName].cmdInput.len > 0:
+      # 2. cmdInput given but not stepCmd: default stepCmd to "sh"
+      steps[sName].stepCmd = "sh"
+
+    # 3. stepCmd given but not cmdInput & 4. both given: use them as-is
 
   result = ProjectConfig(
     name: jsonCfg.getOrFail("name", "project configuration").getStr,

src/test/nim/unit/tconfiguration.nim

@@ -100,7 +100,7 @@ suite "load and save configuration objects":
       # Step with defaulted properties
       pc.steps["test"].name == "test"
       pc.steps["test"].dontSkip == false
-      pc.steps["test"].stepCmd == "sh"
+      pc.steps["test"].stepCmd == "true"
       pc.steps["test"].workingDir == "."
       sameContents(pc.steps["test"].artifacts, @[])
       sameContents(pc.steps["test"].depends, @[])