Merge branch 'fix-320' into 'main'

Make bindings parsing more strict, and validate that strictness

Closes #320

See merge request subplot/subplot!364

2 files changed, 72 insertions, 2 deletions

diff --git a/src/bindings.rs b/src/bindings.rs
index 5fe5887..380b0ed 100644
--- a/src/bindings.rs
+++ b/src/bindings.rs
@@ -423,13 +423,14 @@ pub struct Bindings {
 }
 
 #[derive(Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
 struct ParsedImpl {
     function: String,
     cleanup: Option<String>,
 }
 
 #[derive(Debug, Deserialize)]
-#[serde(transparent)]
+#[serde(transparent, deny_unknown_fields)]
 struct ParsedImplWrapper {
     #[serde(deserialize_with = "deserialize_struct_case_insensitive")]
     pimpl: ParsedImpl,
@@ -444,6 +445,7 @@ impl Deref for ParsedImplWrapper {
 }
 
 #[derive(Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
 struct ParsedBinding {
     given: Option<String>,
     when: Option<String>,
@@ -459,7 +461,7 @@ struct ParsedBinding {
 }
 
 #[derive(Debug, Deserialize)]
-#[serde(transparent)]
+#[serde(transparent, deny_unknown_fields)]
 struct ParsedBindingWrapper {
     #[serde(deserialize_with = "deserialize_struct_case_insensitive")]
     binding: ParsedBinding,
diff --git a/subplot.md b/subplot.md
index 432b571..76e36f2 100644
--- a/subplot.md
+++ b/subplot.md
@@ -812,6 +812,74 @@ given file missing.md
 
 ~~~
 
+### Bindings file strictness - given when then
+
+The bindings file is semi-strict.  For example you must have only one
+of `given`, `when`, or `then` in your binding.
+
+
+```scenario
+given file badbindingsgwt.subplot
+and file badbindingsgwt.md
+and file badbindingsgwt.yaml
+and an installed subplot
+when I try to run subplot docgen --output ignored.html badbindingsgwt.subplot
+then command fails
+and stderr contains "binding has more than one keyword"
+```
+
+~~~{#badbindingsgwt.subplot .file .yaml .numberLines}
+title: Bad bindings cause everything to fail
+markdowns: [badbindingsgwt.md]
+bindings: [badbindingsgwt.yaml]
+~~~
+
+~~~{#badbindingsgwt.md .file .markdown .numberLines}
+# Bad bindings
+```scenario
+given we won't reach here
+```
+~~~
+
+~~~{#badbindingsgwt.yaml .file .yaml .numberLines}
+- given: we won't reach here
+  then: we won't reach here
+~~~
+
+### Bindings file strictness - unknown field
+
+The bindings file is semi-strict.  For example, you must not have keys
+in the bindings file which are not known to Subplot.
+
+
+```scenario
+given file badbindingsuf.subplot
+and file badbindingsuf.md
+and file badbindingsuf.yaml
+and an installed subplot
+when I try to run subplot docgen --output ignored.html badbindingsuf.subplot
+then command fails
+and stderr contains "unknown field `function`"
+```
+
+~~~{#badbindingsuf.subplot .file .yaml .numberLines}
+title: Bad bindings cause everything to fail
+markdowns: [badbindingsuf.md]
+bindings: [badbindingsuf.yaml]
+~~~
+
+~~~{#badbindingsuf.md .file .markdown .numberLines}
+# Bad bindings
+```scenario
+given we won't reach here
+```
+~~~
+
+~~~{#badbindingsuf.yaml .file .yaml .numberLines}
+- given: we won't reach here
+  function: old_school_function
+~~~
+
 ## Functions file
 
 Functions implementing steps are supported in Bash and Python. The