From d8a8c7d103fc4d10ebdec62abd15635315226a9f Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 4 Nov 2022 17:24:01 +0100
Subject: [PATCH 01/13] lint: check approaches and articles

There is not yet a formal spec for an approach `config.json` file or an
article `config.json` file, but I've tried to implement linting them
from the docs for approaches [1][2] and a commit [3] on the csharp
track.

[1] https://github.com/exercism/docs/blob/5509b2f12fac/building/tracks/concept-exercises.md#file-approachesconfigjson
[2] https://github.com/exercism/docs/blob/5509b2f12fac/building/tracks/practice-exercises.md#file-approachesconfigjson
[3] https://github.com/exercism/csharp/commit/4069cca97782
---
 src/lint/approaches_and_articles.nim | 83 ++++++++++++++++++++++++++++
 src/lint/lint.nim                    |  5 +-
 2 files changed, 86 insertions(+), 2 deletions(-)
 create mode 100644 src/lint/approaches_and_articles.nim

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
new file mode 100644
index 00000000..cff519a8
--- /dev/null
+++ b/src/lint/approaches_and_articles.nim
@@ -0,0 +1,83 @@
+import std/[json, strformat, strutils]
+import ".."/helpers
+import "."/validators
+
+type
+  DirKind = enum
+    dkApproaches = "approaches"
+    dkArticles = "articles"
+
+proc hasValidIntroduction(data: JsonNode, path: Path): bool =
+  const k = "introduction"
+  if hasObject(data, k, path):
+    let d = data[k]
+    let checks = [
+      hasArrayOfStrings(d, "authors", path, k, uniqueValues = true),
+      hasArrayOfStrings(d, "contributors", path, k, isRequired = false),
+    ]
+    result = allTrue(checks)
+
+proc isValidApproachOrArticle(data: JsonNode, context: string,
+                              path: Path): bool =
+  if isObject(data, context, path):
+    let checks = [
+      hasString(data, "uuid", path, context, checkIsUuid = true),
+      hasString(data, "slug", path, context, checkIsKebab = true),
+      hasString(data, "title", path, context, maxLen = 255),
+      hasString(data, "blurb", path, context, maxLen = 280),
+      hasArrayOfStrings(data, "authors", path, context, uniqueValues = true),
+      hasArrayOfStrings(data, "contributors", path, context,
+                        isRequired = false),
+    ]
+    result = allTrue(checks)
+
+proc isValidConfig(data: JsonNode, path: Path, dk: DirKind): bool =
+  if isObject(data, jsonRoot, path):
+    let checks = [
+      if dk == dkApproaches: hasValidIntroduction(data, path) else: true,
+      hasArrayOf(data, $dk, path, isValidApproachOrArticle, isRequired = false),
+    ]
+    result = allTrue(checks)
+
+proc isConfigMissingOrValid(dir: Path, dk: DirKind): bool =
+  result = true
+  let configPath = dir / &".{dk}" / "config.json"
+  if fileExists(configPath):
+    let j = parseJsonFile(configPath, result)
+    if j != nil:
+      if not isValidConfig(j, configPath, dk):
+        result = false
+
+proc isEverySnippetValid(exerciseDir: Path, dk: DirKind): bool =
+  result = true
+  for dir in getSortedSubdirs(exerciseDir / &".{dk}"):
+    let snippetPath = block:
+      let ext = if dk == dkApproaches: "txt" else: "md"
+      dir / &"snippet.{ext}"
+    if fileExists(snippetPath):
+      let contents = readFile(snippetPath)
+      var numLines = 0
+      for line in contents.splitLines():
+        if not (line.startsWith("```") and dk == dkArticles):
+          inc numLines
+      dec numLines # Allow 8 lines with a final newline.
+      const maxNumLines = 8
+      if numLines > maxNumLines:
+        let msg = &"The file is {numLines} lines long, but it must be at " &
+                  &"most {maxNumLines} lines long"
+        result.setFalseAndPrint(msg, snippetPath)
+
+proc isDirValid(exerciseDir: Path): bool =
+  result = true
+  for dk in DirKind:
+    if not isConfigMissingOrValid(exerciseDir, dk):
+      result = false
+    if not isEverySnippetValid(exerciseDir, dk):
+      result = false
+
+proc isEveryApproachAndArticleValid*(trackDir: Path): bool =
+  result = true
+  for exerciseKind in ["concept", "practice"]:
+    for exerciseDir in getSortedSubdirs(trackDir / "exercises" / exerciseKind):
+      if not isDirValid(exerciseDir):
+        result = false
diff --git a/src/lint/lint.nim b/src/lint/lint.nim
index dd4f5804..35dfc3ce 100644
--- a/src/lint/lint.nim
+++ b/src/lint/lint.nim
@@ -1,7 +1,7 @@
 import std/[strformat, strutils]
 import ".."/[cli, helpers]
-import "."/[concept_exercises, concepts, docs, practice_exercises,
-            track_config, validators]
+import "."/[approaches_and_articles, concept_exercises, concepts, docs,
+            practice_exercises, track_config, validators]
 
 proc allChecksPass(trackDir: Path): bool =
   ## Returns true if all the linting checks pass for the track at `trackDir`.
@@ -16,6 +16,7 @@ proc allChecksPass(trackDir: Path): bool =
     isEveryConceptConfigValid(trackDir),
     isEveryConceptExerciseConfigValid(trackDir),
     isEveryPracticeExerciseConfigValid(trackDir),
+    isEveryApproachAndArticleValid(trackDir),
     sharedExerciseDocsExist(trackDir),
     trackDocsExist(trackDir),
   ]

From 0e70d2b14f80d93c6df762477f1bab6836805b06 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 4 Nov 2022 17:50:01 +0100
Subject: [PATCH 02/13] lint(approaches_and_articles): inline `isDirValid`

---
 src/lint/approaches_and_articles.nim | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index cff519a8..7fbdeb16 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -67,17 +67,12 @@ proc isEverySnippetValid(exerciseDir: Path, dk: DirKind): bool =
                   &"most {maxNumLines} lines long"
         result.setFalseAndPrint(msg, snippetPath)
 
-proc isDirValid(exerciseDir: Path): bool =
-  result = true
-  for dk in DirKind:
-    if not isConfigMissingOrValid(exerciseDir, dk):
-      result = false
-    if not isEverySnippetValid(exerciseDir, dk):
-      result = false
-
 proc isEveryApproachAndArticleValid*(trackDir: Path): bool =
   result = true
   for exerciseKind in ["concept", "practice"]:
     for exerciseDir in getSortedSubdirs(trackDir / "exercises" / exerciseKind):
-      if not isDirValid(exerciseDir):
-        result = false
+      for dk in DirKind:
+        if not isConfigMissingOrValid(exerciseDir, dk):
+          result = false
+        if not isEverySnippetValid(exerciseDir, dk):
+          result = false

From d79953b4149ae7c566690b1405760d9777cb9b44 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 4 Nov 2022 19:03:01 +0100
Subject: [PATCH 03/13] clint(approaches_and_articles): add dots to `DirKind`
 strings

---
 src/lint/approaches_and_articles.nim | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index 7fbdeb16..fe3564ef 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -4,8 +4,8 @@ import "."/validators
 
 type
   DirKind = enum
-    dkApproaches = "approaches"
-    dkArticles = "articles"
+    dkApproaches = ".approaches"
+    dkArticles = ".articles"
 
 proc hasValidIntroduction(data: JsonNode, path: Path): bool =
   const k = "introduction"
@@ -33,15 +33,16 @@ proc isValidApproachOrArticle(data: JsonNode, context: string,
 
 proc isValidConfig(data: JsonNode, path: Path, dk: DirKind): bool =
   if isObject(data, jsonRoot, path):
+    let k = dk.`$`[1..^1] # Remove dot.
     let checks = [
       if dk == dkApproaches: hasValidIntroduction(data, path) else: true,
-      hasArrayOf(data, $dk, path, isValidApproachOrArticle, isRequired = false),
+      hasArrayOf(data, k, path, isValidApproachOrArticle, isRequired = false),
     ]
     result = allTrue(checks)
 
 proc isConfigMissingOrValid(dir: Path, dk: DirKind): bool =
   result = true
-  let configPath = dir / &".{dk}" / "config.json"
+  let configPath = dir / $dk / "config.json"
   if fileExists(configPath):
     let j = parseJsonFile(configPath, result)
     if j != nil:
@@ -50,7 +51,7 @@ proc isConfigMissingOrValid(dir: Path, dk: DirKind): bool =
 
 proc isEverySnippetValid(exerciseDir: Path, dk: DirKind): bool =
   result = true
-  for dir in getSortedSubdirs(exerciseDir / &".{dk}"):
+  for dir in getSortedSubdirs(exerciseDir / $dk):
     let snippetPath = block:
       let ext = if dk == dkApproaches: "txt" else: "md"
       dir / &"snippet.{ext}"

From 6cc4380de777ba380ec2294d5bd3f3a654692d7d Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Wed, 9 Nov 2022 13:39:01 +0100
Subject: [PATCH 04/13] lint(approaches_and_articles): error for 8 newlines
 then non-newline

Make `configlet lint` produce an error for a snippet with 8 newline
characters then non-newline content on the 9th line, e.g.:

    1\n2\n3\n4\n5\n6\n7\n8\n9

Note that this means we do not count lines like `wc`:

    $ printf '1\n2\n3\n4\n5\n6\n7\n8' | wc -l
    7
    $ printf '1\n2\n3\n4\n5\n6\n7\n8\n' | wc -l
    8
    $ printf '1\n2\n3\n4\n5\n6\n7\n8\n9' | wc -l
    8
    $ printf '1\n2\n3\n4\n5\n6\n7\n8\n9\n' | wc -l
    9
---
 src/lint/approaches_and_articles.nim | 25 ++++++----
 tests/test_lint.nim                  | 69 +++++++++++++++++++++++++++-
 2 files changed, 85 insertions(+), 9 deletions(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index fe3564ef..b4c8eb8f 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -49,6 +49,19 @@ proc isConfigMissingOrValid(dir: Path, dk: DirKind): bool =
       if not isValidConfig(j, configPath, dk):
         result = false
 
+func countLinesWithoutCodeFence(s: string, dk: DirKind): int =
+  ## Returns the number of lines in `s`, but:
+  ##
+  ## - excluding lines that open or close a Markdown code fence.
+  ## - including a final line that does not end in a newline character.
+  result = 0
+  if s.len > 0:
+    for line in s.splitLines():
+      if not (line.startsWith("```") and dk == dkArticles):
+        inc result
+    if s[^1] in ['\n', '\l']:
+      dec result
+
 proc isEverySnippetValid(exerciseDir: Path, dk: DirKind): bool =
   result = true
   for dir in getSortedSubdirs(exerciseDir / $dk):
@@ -57,15 +70,11 @@ proc isEverySnippetValid(exerciseDir: Path, dk: DirKind): bool =
       dir / &"snippet.{ext}"
     if fileExists(snippetPath):
       let contents = readFile(snippetPath)
-      var numLines = 0
-      for line in contents.splitLines():
-        if not (line.startsWith("```") and dk == dkArticles):
-          inc numLines
-      dec numLines # Allow 8 lines with a final newline.
-      const maxNumLines = 8
-      if numLines > maxNumLines:
+      const maxLines = 8
+      let numLines = countLinesWithoutCodeFence(contents, dk)
+      if numLines > maxLines:
         let msg = &"The file is {numLines} lines long, but it must be at " &
-                  &"most {maxNumLines} lines long"
+                  &"most {maxLines} lines long"
         result.setFalseAndPrint(msg, snippetPath)
 
 proc isEveryApproachAndArticleValid*(trackDir: Path): bool =
diff --git a/tests/test_lint.nim b/tests/test_lint.nim
index 925f7a59..83d42c3f 100644
--- a/tests/test_lint.nim
+++ b/tests/test_lint.nim
@@ -1,5 +1,6 @@
-import std/unittest
+import std/[strutils, unittest]
 import "."/lint/validators
+import "."/lint/approaches_and_articles {.all.}
 
 proc testIsKebabCase =
   suite "isKebabCase":
@@ -279,11 +280,77 @@ proc testIsFilesPattern =
         isFilesPattern("somedir/%{pascal_slug}/%{snake_slug}.suffix")
         isFilesPattern("%{pascal_slug}/filename.suffix")
 
+proc testCountLinesWithoutCodeFence =
+  suite "countLinesWithoutCodeFence":
+    test "without code fence":
+      const dk = dkArticles
+      check:
+        countLinesWithoutCodeFence("", dk) == 0
+        countLinesWithoutCodeFence("a", dk) == 1
+        countLinesWithoutCodeFence("a\n", dk) == 1
+        countLinesWithoutCodeFence("foo\n", dk) == 1
+        countLinesWithoutCodeFence("foo\nb", dk) == 2
+        countLinesWithoutCodeFence("foo\nbar", dk) == 2
+        countLinesWithoutCodeFence("foo\nbar\n", dk) == 2
+        countLinesWithoutCodeFence("foo\nbar\nfoo", dk) == 3
+
+    test "with code fence only":
+      const s = """
+        ```nim
+        echo "foo"
+        ```""".unindent()
+      check:
+        countLinesWithoutCodeFence(s, dkArticles) == 1
+        countLinesWithoutCodeFence(s, dkApproaches) == 3
+
+    test "with code fence at start":
+      const s = """
+        ```nim
+        echo "foo"
+        ```
+
+      Some content.
+      """.unindent()
+      check:
+        countLinesWithoutCodeFence(s, dkArticles) == 3
+        countLinesWithoutCodeFence(s, dkApproaches) == 5
+
+    test "with code fence at end":
+      const s = """
+        # Some header
+
+        Some content.
+
+        ```nim
+        echo "foo"
+        ```
+      """.unindent()
+      check:
+        countLinesWithoutCodeFence(s, dkArticles) == 5
+        countLinesWithoutCodeFence(s, dkApproaches) == 7
+
+    test "with code fence in middle":
+      const s = """
+        # Some header
+
+        Some content.
+
+        ```nim
+        echo "foo"
+        ```
+
+        Some content.
+      """.unindent()
+      check:
+        countLinesWithoutCodeFence(s, dkArticles) == 7
+        countLinesWithoutCodeFence(s, dkApproaches) == 9
+
 proc main =
   testIsKebabCase()
   testIsUuidV4()
   testExtractPlaceholders()
   testIsFilesPattern()
+  testCountLinesWithoutCodeFence()
 
 main()
 {.used.}

From 3adba39d7d538822f19994adac75d4b23f2b3dee Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Wed, 9 Nov 2022 16:36:01 +0100
Subject: [PATCH 05/13] lint(approaches_and_articles): do not error for missing
 `introduction`

---
 src/lint/approaches_and_articles.nim | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index b4c8eb8f..eafbfe83 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -9,7 +9,7 @@ type
 
 proc hasValidIntroduction(data: JsonNode, path: Path): bool =
   const k = "introduction"
-  if hasObject(data, k, path):
+  if hasObject(data, k, path, isRequired = false):
     let d = data[k]
     let checks = [
       hasArrayOfStrings(d, "authors", path, k, uniqueValues = true),

From a260510691ad7efad30d69bb1ce48ca8bae09ef3 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Thu, 10 Nov 2022 16:36:02 +0100
Subject: [PATCH 06/13] lint(articles_and_approaches): error for missing
 `config.json`

---
 src/lint/approaches_and_articles.nim | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index eafbfe83..880624b7 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -42,12 +42,22 @@ proc isValidConfig(data: JsonNode, path: Path, dk: DirKind): bool =
 
 proc isConfigMissingOrValid(dir: Path, dk: DirKind): bool =
   result = true
-  let configPath = dir / $dk / "config.json"
+  let dkPath = dir / $dk
+  let configPath = dkPath / "config.json"
   if fileExists(configPath):
     let j = parseJsonFile(configPath, result)
     if j != nil:
       if not isValidConfig(j, configPath, dk):
         result = false
+  else:
+    if dk == dkApproaches and fileExists(dkPath / "introduction.md"):
+      let msg =  &"The below directory has an 'introduction.md' file, but " &
+                 "does not contain a 'config.json' file"
+      result.setFalseAndPrint(msg, dkPath)
+    for dir in getSortedSubdirs(dkPath, relative = true):
+      let msg = &"The below directory has a '{dir}' subdirectory, but does " &
+                "not contain a 'config.json' file"
+      result.setFalseAndPrint(msg, dkPath)
 
 func countLinesWithoutCodeFence(s: string, dk: DirKind): int =
   ## Returns the number of lines in `s`, but:

From 6747ce1cddae367916175ab8611b2413165e2644 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Thu, 10 Nov 2022 16:36:03 +0100
Subject: [PATCH 07/13] lint: print that approaches/articles were linted

---
 src/lint/lint.nim | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/lint/lint.nim b/src/lint/lint.nim
index 35dfc3ce..a2f39a0f 100644
--- a/src/lint/lint.nim
+++ b/src/lint/lint.nim
@@ -46,6 +46,7 @@ proc lint*(conf: Conf) =
       - Every concept exercise has a valid .meta/config.json file
       - Every practice exercise has the required .md files
       - Every practice exercise has a valid .meta/config.json file
+      - Every approach and article is valid
       - Required track docs are present
       - Required shared exercise docs are present""".dedent()
     if printedWarning:

From c5ee39ee356c7f2c7aac1047ebe2f7cb189f435e Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Thu, 10 Nov 2022 16:36:04 +0100
Subject: [PATCH 08/13] lint(approaches_and_articles), helpers: error for
 missing slug dir

---
 src/helpers.nim                      | 1 +
 src/lint/approaches_and_articles.nim | 9 ++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/helpers.nim b/src/helpers.nim
index 53ca746c..37b49a2b 100644
--- a/src/helpers.nim
+++ b/src/helpers.nim
@@ -92,6 +92,7 @@ proc dirExists*(path: Path): bool {.borrow.}
 proc fileExists*(path: Path): bool {.borrow.}
 proc readFile*(path: Path): string {.borrow.}
 proc writeFile*(path: Path; content: string) {.borrow.}
+proc parentDir*(path: Path): string {.borrow.}
 
 func toLineAndCol(s: string; offset: Natural): tuple[line: int; col: int] =
   ## Returns the line and column number corresponding to the `offset` in `s`.
diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index 880624b7..2028c38f 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -1,4 +1,4 @@
-import std/[json, strformat, strutils]
+import std/[json, os, strformat, strutils]
 import ".."/helpers
 import "."/validators
 
@@ -30,6 +30,13 @@ proc isValidApproachOrArticle(data: JsonNode, context: string,
                         isRequired = false),
     ]
     result = allTrue(checks)
+    if result:
+      let slug = data["slug"].getStr()
+      let slugDir = path.parentDir() / slug
+      if not dirExists(slugDir):
+        let msg = &"A 'slug' value is '{slug}', but there is no sibling " &
+                  "directory with that name"
+        result.setFalseAndPrint(msg, path)
 
 proc isValidConfig(data: JsonNode, path: Path, dk: DirKind): bool =
   if isObject(data, jsonRoot, path):

From 0300ae6a43deb73429ee2de81982d14c5cf27307 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 11 Nov 2022 13:56:01 +0100
Subject: [PATCH 09/13] lint(approaches_and_articles): improve msg for missing
 dir

---
 src/lint/approaches_and_articles.nim | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index 2028c38f..37addd63 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -32,11 +32,11 @@ proc isValidApproachOrArticle(data: JsonNode, context: string,
     result = allTrue(checks)
     if result:
       let slug = data["slug"].getStr()
-      let slugDir = path.parentDir() / slug
+      let slugDir = Path(path.parentDir() / slug)
       if not dirExists(slugDir):
-        let msg = &"A 'slug' value is '{slug}', but there is no sibling " &
-                  "directory with that name"
-        result.setFalseAndPrint(msg, path)
+        let msg = &"A config.json '{context}.slug' value is '{slug}', but " &
+                  "there is no corresponding directory at the below location"
+        result.setFalseAndPrint(msg, slugDir)
 
 proc isValidConfig(data: JsonNode, path: Path, dk: DirKind): bool =
   if isObject(data, jsonRoot, path):

From fe94cf28a9a1f8d5e445ef006bd034fee7c49768 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 11 Nov 2022 13:56:02 +0100
Subject: [PATCH 10/13] lint(approaches_and_articles): error for missing
 intro/content/snippet

Try to implement these checks for `.approaches/config.json`

- If the `introduction.authors` array is non-empty, there must be a non-empty `introduction.md` file
- Any `approaches.slug` value must have a corresponding non-empty `<slug>/content.md` file
- Any `approaches.slug` value must have a corresponding non-empty `<slug>/snippet.txt` file

And these checks for `.articles/config.json`

- Any `articles.slug` value must have a corresponding non-empty `<slug>/content.md` file
- Any `articles.slug` value must have a corresponding non-empty `<slug>/snippet.md` file

Some output:

    $ configlet lint
    [...]
    The config.json 'introduction' object is present, but there is no corresponding introduction file at the below location:
    ./exercises/practice/bob/.approaches/introduction.md

    A config.json 'approaches.slug' value is 'if', but there is no corresponding content file at the below location:
    ./exercises/practice/bob/.approaches/if/content.md

    A config.json 'approaches.slug' value is 'answer-array', but there is no corresponding snippet file at the below location:
    ./exercises/practice/bob/.approaches/answer-array/snippet.txt

    A config.json 'articles.slug' value is 'performance', but there is no corresponding content file at the below location:
    ./exercises/practice/bob/.articles/performance/content.md

    A config.json 'articles.slug' value is 'performance', but there is no corresponding snippet file at the below location:
    ./exercises/practice/bob/.articles/performance/snippet.md
---
 src/lint/approaches_and_articles.nim | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index 37addd63..ad69d7dd 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -7,6 +7,14 @@ type
     dkApproaches = ".approaches"
     dkArticles = ".articles"
 
+proc setFalseIfFileMissingOrEmpty(b: var bool, path: Path, msgMissing: string) =
+  if fileExists(path):
+    if path.readFile().len == 0:
+      let msg = &"The below file is empty"
+      b.setFalseAndPrint(msg, path)
+  else:
+    b.setFalseAndPrint(msgMissing, path)
+
 proc hasValidIntroduction(data: JsonNode, path: Path): bool =
   const k = "introduction"
   if hasObject(data, k, path, isRequired = false):
@@ -16,6 +24,11 @@ proc hasValidIntroduction(data: JsonNode, path: Path): bool =
       hasArrayOfStrings(d, "contributors", path, k, isRequired = false),
     ]
     result = allTrue(checks)
+  if result and data.hasKey(k):
+    let introductionPath = Path(path.parentDir() / "introduction.md")
+    let msg = &"The config.json '{k}' object is present, but there is no " &
+              "corresponding introduction file at the below location"
+    result.setFalseIfFileMissingOrEmpty(introductionPath, msg)
 
 proc isValidApproachOrArticle(data: JsonNode, context: string,
                               path: Path): bool =
@@ -32,11 +45,23 @@ proc isValidApproachOrArticle(data: JsonNode, context: string,
     result = allTrue(checks)
     if result:
       let slug = data["slug"].getStr()
-      let slugDir = Path(path.parentDir() / slug)
+      let dkDir = path.parentDir()
+      let slugDir = Path(dkDir / slug)
       if not dirExists(slugDir):
         let msg = &"A config.json '{context}.slug' value is '{slug}', but " &
                   "there is no corresponding directory at the below location"
         result.setFalseAndPrint(msg, slugDir)
+      block:
+        let contentPath = slugDir / "content.md"
+        let msg = &"A config.json '{context}.slug' value is '{slug}', but " &
+                  "there is no corresponding content file at the below location"
+        result.setFalseIfFileMissingOrEmpty(contentPath, msg)
+      block:
+        let ext = if dkDir.endsWith($dkApproaches): "txt" else: "md"
+        let snippetPath = slugDir / &"snippet.{ext}"
+        let msg = &"A config.json '{context}.slug' value is '{slug}', but " &
+                  "there is no corresponding snippet file at the below location"
+        result.setFalseIfFileMissingOrEmpty(snippetPath, msg)
 
 proc isValidConfig(data: JsonNode, path: Path, dk: DirKind): bool =
   if isObject(data, jsonRoot, path):

From 5e710b26bc4f56a6738eeaab8b430c355af56a7b Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 11 Nov 2022 15:20:01 +0100
Subject: [PATCH 11/13] lint(approaches_and_articles): remove an `if result`

---
 src/lint/approaches_and_articles.nim | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index ad69d7dd..fc8e2347 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -24,7 +24,7 @@ proc hasValidIntroduction(data: JsonNode, path: Path): bool =
       hasArrayOfStrings(d, "contributors", path, k, isRequired = false),
     ]
     result = allTrue(checks)
-  if result and data.hasKey(k):
+  if data.kind == JObject and data.hasKey(k):
     let introductionPath = Path(path.parentDir() / "introduction.md")
     let msg = &"The config.json '{k}' object is present, but there is no " &
               "corresponding introduction file at the below location"

From abe6d593cc1e80894f4a10de4223c68efa2fc6a9 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 11 Nov 2022 15:20:02 +0100
Subject: [PATCH 12/13] lint(approaches_and_articles): error for dir not in
 config slugs

Example output:

    $ configlet lint
    [...]
    There is no 'approaches.slug' key with the value 'performance', but a sibling directory exists with that name:
    ../exercism-tracks/csharp/exercises/practice/reverse-string/.approaches/config.json
---
 src/lint/approaches_and_articles.nim | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index fc8e2347..42fe9a6b 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -63,6 +63,15 @@ proc isValidApproachOrArticle(data: JsonNode, context: string,
                   "there is no corresponding snippet file at the below location"
         result.setFalseIfFileMissingOrEmpty(snippetPath, msg)
 
+proc getSlugs(data: JsonNode, k: string): seq[string] =
+  result = @[]
+  if data.kind == JObject and data.hasKey(k):
+    if data[k].kind == JArray:
+      let elems = data[k].getElems()
+      for e in elems:
+        if e.kind == JObject and e.hasKey("slug") and e["slug"].kind == JString:
+          result.add e["slug"].getStr()
+
 proc isValidConfig(data: JsonNode, path: Path, dk: DirKind): bool =
   if isObject(data, jsonRoot, path):
     let k = dk.`$`[1..^1] # Remove dot.
@@ -71,6 +80,13 @@ proc isValidConfig(data: JsonNode, path: Path, dk: DirKind): bool =
       hasArrayOf(data, k, path, isValidApproachOrArticle, isRequired = false),
     ]
     result = allTrue(checks)
+    if result:
+      let slugsInConfig = getSlugs(data, k)
+      for dir in getSortedSubdirs(path.parentDir().Path, relative = true):
+        if dir.string notin slugsInConfig:
+          let msg = &"There is no '{k}.slug' key with the value '{dir}', " &
+                    &"but a sibling directory exists with that name"
+          result.setFalseAndPrint(msg, path)
 
 proc isConfigMissingOrValid(dir: Path, dk: DirKind): bool =
   result = true

From fe35e8631a662047afffd04efa3035cf3ebfb1ca Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 11 Nov 2022 17:59:01 +0100
Subject: [PATCH 13/13] lint(approaches_and_articles): fix whitespace

Appease nimpretty.
---
 src/lint/approaches_and_articles.nim | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lint/approaches_and_articles.nim b/src/lint/approaches_and_articles.nim
index 42fe9a6b..2ddd8d48 100644
--- a/src/lint/approaches_and_articles.nim
+++ b/src/lint/approaches_and_articles.nim
@@ -99,8 +99,8 @@ proc isConfigMissingOrValid(dir: Path, dk: DirKind): bool =
         result = false
   else:
     if dk == dkApproaches and fileExists(dkPath / "introduction.md"):
-      let msg =  &"The below directory has an 'introduction.md' file, but " &
-                 "does not contain a 'config.json' file"
+      let msg = &"The below directory has an 'introduction.md' file, but " &
+                "does not contain a 'config.json' file"
       result.setFalseAndPrint(msg, dkPath)
     for dir in getSortedSubdirs(dkPath, relative = true):
       let msg = &"The below directory has a '{dir}' subdirectory, but does " &