Merge branch 'all-bindings' into 'main'

feat: when more than one bindings match a step, list all of them

Closes #120

See merge request subplot/subplot!188

5 files changed, 77 insertions, 23 deletions

diff --git a/src/bindings.rs b/src/bindings.rs
index d17460f..2e927cd 100644
--- a/src/bindings.rs
+++ b/src/bindings.rs
@@ -1,4 +1,5 @@
 use super::MatchedStep;
+use super::MatchedSteps;
 use super::PartialStep;
 use super::ScenarioStep;
 use super::StepKind;
@@ -170,7 +171,7 @@ impl Binding {
         let caps = self.regex.captures(step_text)?;
 
         // If there is only one capture, it's the whole string.
-        let mut m = MatchedStep::new(self.kind(), &self.function, self.cleanup(), &self.types);
+        let mut m = MatchedStep::new(self, &self.types);
         if caps.len() == 1 {
             m.append_part(PartialStep::uncaptured(step_text));
             return Some(m);
@@ -480,16 +481,23 @@ impl Bindings {
     /// Find the binding matching a given scenario step, if there is
     /// exactly one.
     pub fn find(&self, step: &ScenarioStep) -> Result<MatchedStep> {
-        let mut matches = self
+        let mut matches: Vec<MatchedStep> = self
             .bindings()
             .iter()
-            .filter_map(|b| b.match_with_step(step));
-        match matches.next() {
-            None => Err(SubplotError::BindingUnknown(step.to_string())),
-            Some(matched) => match matches.next() {
-                None => Ok(matched),
-                Some(_) => Err(SubplotError::BindingNotUnique(step.to_string())),
-            },
+            .filter_map(|b| b.match_with_step(step))
+            .collect();
+        if matches.len() > 1 {
+            // Too many matching bindings.
+            Err(SubplotError::BindingNotUnique(
+                step.to_string(),
+                MatchedSteps::new(matches),
+            ))
+        } else if let Some(m) = matches.pop() {
+            // Exactly one matching binding.
+            Ok(m)
+        } else {
+            // No matching bindings.
+            Err(SubplotError::BindingUnknown(step.to_string()))
         }
     }
 
@@ -719,7 +727,7 @@ mod test_bindings {
         );
         assert!(matches!(
             bindings.find(&step),
-            Err(SubplotError::BindingNotUnique(_))
+            Err(SubplotError::BindingNotUnique(_, _))
         ));
     }
 
diff --git a/src/error.rs b/src/error.rs
index eb70e28..532714b 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -1,3 +1,5 @@
+use crate::matches::MatchedSteps;
+
 use std::path::PathBuf;
 use std::process::Output;
 
@@ -46,8 +48,8 @@ pub enum SubplotError {
     ///
     /// THis may be due to bindings being too general, or having unusual
     /// overlaps in their matching
-    #[error("more than one binding matches: {0}")]
-    BindingNotUnique(String),
+    #[error("more than one binding matches step {0}:\n{1}")]
+    BindingNotUnique(String, MatchedSteps),
 
     /// A binding in the bindings file doesn't specify a known keyword.
     #[error("binding doesn't specify known keyword: {0}")]
diff --git a/src/lib.rs b/src/lib.rs
index 960e3ef..e2b1431 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -60,6 +60,7 @@ pub use parser::parse_scenario_snippet;
 mod matches;
 pub use matches::MatchedScenario;
 pub use matches::MatchedStep;
+pub use matches::MatchedSteps;
 pub use matches::PartialStep;
 pub use matches::StepSnippet;
 
diff --git a/src/matches.rs b/src/matches.rs
index 472b475..88d2c55 100644
--- a/src/matches.rs
+++ b/src/matches.rs
@@ -1,3 +1,4 @@
+use crate::Binding;
 use crate::Result;
 use crate::Scenario;
 use crate::StepKind;
@@ -34,6 +35,30 @@ impl MatchedScenario {
     }
 }
 
+/// A list of matched steps.
+#[derive(Debug)]
+pub struct MatchedSteps {
+    matches: Vec<MatchedStep>,
+}
+
+impl MatchedSteps {
+    /// Create new set of steps that match a scenario step.
+    pub fn new(matches: Vec<MatchedStep>) -> Self {
+        Self { matches }
+    }
+}
+
+impl std::fmt::Display for MatchedSteps {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
+        let matches: Vec<String> = self
+            .matches
+            .iter()
+            .map(|m| format!("{}", m.pattern()))
+            .collect();
+        write!(f, "{}", matches.join("\n"))
+    }
+}
+
 /// A matched binding and scenario step, with captured parts.
 ///
 /// A MatchedStep is a sequence of partial steps, each representing
@@ -41,6 +66,7 @@ impl MatchedScenario {
 #[derive(Debug, Serialize, Deserialize)]
 pub struct MatchedStep {
     kind: StepKind,
+    pattern: String,
     text: String,
     parts: Vec<PartialStep>,
     function: String,
@@ -50,18 +76,14 @@ pub struct MatchedStep {
 
 impl MatchedStep {
     /// Return a new empty match. Empty means it has no step parts.
-    pub fn new(
-        kind: StepKind,
-        function: &str,
-        cleanup: Option<&str>,
-        types: &HashMap<String, CaptureType>,
-    ) -> MatchedStep {
+    pub fn new(binding: &Binding, types: &HashMap<String, CaptureType>) -> MatchedStep {
         MatchedStep {
-            kind,
+            kind: binding.kind(),
+            pattern: binding.pattern().to_string(),
             text: "".to_string(),
             parts: vec![],
-            function: function.to_string(),
-            cleanup: cleanup.map(String::from),
+            function: binding.function().to_string(),
+            cleanup: binding.cleanup().map(String::from),
             types: types.clone(),
         }
     }
@@ -87,6 +109,10 @@ impl MatchedStep {
         self.parts.iter()
     }
 
+    fn pattern(&self) -> String {
+        self.pattern.to_string()
+    }
+
     fn text(&self) -> String {
         let mut t = String::new();
         for part in self.parts() {
diff --git a/subplot.md b/subplot.md
index 6ddc2c7..07c07de 100644
--- a/subplot.md
+++ b/subplot.md
@@ -2561,7 +2561,9 @@ then command fails
 title: Two bindings match
 template: python
 bindings:
-- badbindings.yaml
+- twobindings.yaml
+functions:
+- a_function.py
 ...
 # Broken scenario because step has two possible bindings
 
@@ -2570,12 +2572,27 @@ given a binding
 ```
 ~~~~
 
+~~~{#twobindings.yaml .file .yaml}
+- given: a {xyzzy}
+  function: a_function
+- given: a {plugh}
+  function: a_function
+~~~
+
+~~~{#a_function.py .file .python}
+def a_function(ctx):
+    assert 0
+~~~
+
 ```scenario
 given file twobindings.md
-and file badbindings.yaml
+and file twobindings.yaml
+given file a_function.py
 and an installed subplot
 when I try to run subplot codegen --run twobindings.md -o test.py
 then command fails
+then stderr contains "xyzzy"
+then stderr contains "plugh"
 ```