From 84a44c924655f582fc5f0060e904d800a820cdc6 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Thu, 16 Sep 2021 23:37:12 +0200
Subject: [PATCH 1/2] lint(track_config): check for empty `practices`

With this commit, `configlet lint` now checks that a track-level
`config.json` file follows the below rule:

- The `exercises.practice[].practices` value must be a non-empty array
  of strings if `exercises.practice[].status` is not equal to
  `deprecated`

The check is currently implemented as a warning. That is, a violation
does not by itself cause configlet to exit with a non-zero exit code.
---
 src/lint/track_config.nim | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/lint/track_config.nim b/src/lint/track_config.nim
index bd409c95..0c0f7479 100644
--- a/src/lint/track_config.nim
+++ b/src/lint/track_config.nim
@@ -542,6 +542,8 @@ proc checkExercisesPCP(exercises: seq[ConceptExercise] | seq[PracticeExercise];
 
   when exercises is seq[ConceptExercise]:
     var conceptExercisesWithEmptyPrereqs = newSeq[string]()
+  else:
+    var countPracticeExercisesWithEmptyPractices = 0
 
   for exercise in exercises:
     let conceptsOrPractices =
@@ -555,11 +557,13 @@ proc checkExercisesPCP(exercises: seq[ConceptExercise] | seq[PracticeExercise];
     case status
     of sMissing, sBeta, sActive:
       # Check either `concepts` or `practices`
-      # TODO: enable the `practices` check when more tracks have populated them.
-      when exercise is ConceptExercise:
-        if conceptsOrPractices.len == 0:
+      if conceptsOrPractices.len == 0:
+        when exercise is ConceptExercise:
           let msg = statusMsg(exercise, &"an empty array of `{conceptsOrPracticesStr}`")
           b.setFalseAndPrint(msg, path)
+        else:
+          # TODO: Make each empty `practices` an error, not a warning.
+          inc countPracticeExercisesWithEmptyPractices
 
       # Check `prerequisites`
       when exercise is ConceptExercise:
@@ -601,6 +605,11 @@ proc checkExercisesPCP(exercises: seq[ConceptExercise] | seq[PracticeExercise];
       msg.add " each have an empty array of `prerequisites`, but only one " &
               "Concept Exercise is allowed to have that"
       b.setFalseAndPrint(msg, path)
+  else:
+    if countPracticeExercisesWithEmptyPractices > 0:
+      let msg = &"{countPracticeExercisesWithEmptyPractices} user-facing " &
+                 "Practice Exercises have an empty `practices` array"
+      warn(msg, path)
 
 proc checkExerciseSlugsAndForegone(exercises: Exercises; b: var bool;
                                    path: Path) =

From 862ebfe7bd23be8e26772c723f23f9c96450dace Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Thu, 16 Sep 2021 23:37:13 +0200
Subject: [PATCH 2/2] lint(track_config): check for empty PE `prerequisites`

With this commit, `configlet lint` now checks that a track-level
`config.json` file follows the below rule:

- The `exercises.practice[].prerequisites` value must be a non-empty
  array of strings if `exercises.practice[].status` is not equal to
  `deprecated`

The check is currently implemented as a warning. That is, a violation
does not by itself cause configlet to exit with a non-zero exit code.
---
 src/lint/track_config.nim | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/lint/track_config.nim b/src/lint/track_config.nim
index 0c0f7479..20d5d714 100644
--- a/src/lint/track_config.nim
+++ b/src/lint/track_config.nim
@@ -544,6 +544,7 @@ proc checkExercisesPCP(exercises: seq[ConceptExercise] | seq[PracticeExercise];
     var conceptExercisesWithEmptyPrereqs = newSeq[string]()
   else:
     var countPracticeExercisesWithEmptyPractices = 0
+    var countPracticeExercisesWithEmptyPrereqs = 0
 
   for exercise in exercises:
     let conceptsOrPractices =
@@ -576,12 +577,10 @@ proc checkExercisesPCP(exercises: seq[ConceptExercise] | seq[PracticeExercise];
                       "empty array of `prerequisites`"
             b.setFalseAndPrint(msg, path)
         else:
-          # TODO: enable the Practice Exercise `prerequisites` check when more
-          # tracks have populated them.
-          if false:
-            if exercise.prerequisites.len == 0:
-              let msg = statusMsg(exercise, "an empty array of `prerequisites`")
-              b.setFalseAndPrint(msg, path)
+          # TODO: Make an empty Practice Exercise `prerequisites` array an error,
+          # not a warning
+          if exercise.prerequisites.len == 0:
+            inc countPracticeExercisesWithEmptyPrereqs
 
     of sDeprecated:
       # Check either `concepts` or `practices`
@@ -610,6 +609,10 @@ proc checkExercisesPCP(exercises: seq[ConceptExercise] | seq[PracticeExercise];
       let msg = &"{countPracticeExercisesWithEmptyPractices} user-facing " &
                  "Practice Exercises have an empty `practices` array"
       warn(msg, path)
+    if countPracticeExercisesWithEmptyPrereqs > 0:
+      let msg = &"{countPracticeExercisesWithEmptyPrereqs} user-facing " &
+                 "Practice Exercises have an empty `prerequisites` array"
+      warn(msg, path)
 
 proc checkExerciseSlugsAndForegone(exercises: Exercises; b: var bool;
                                    path: Path) =