From a3d768162e70004d207a40d803f5d17eeea8593a Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Sat, 2 Apr 2022 08:58:48 +0300
Subject: refactor: collect warnings for a document in its Document

Change places where warnings used to be written out so the warnings
are pushed into the list in Document instead.

Sponsored-by: author
---
 src/doc.rs   | 23 +++++++++++------------
 src/error.rs | 36 ++++++++++++++++++++++++++++++++++++
 src/lib.rs   |  2 ++
 3 files changed, 49 insertions(+), 12 deletions(-)

diff --git a/src/doc.rs b/src/doc.rs
index 2ff1484..d6ab697 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -13,6 +13,7 @@ use crate::ScenarioStep;
 use crate::Style;
 use crate::{bindings::CaptureType, parser::parse_scenario_snippet};
 use crate::{Result, SubplotError};
+use crate::{Warning, Warnings};
 
 use std::collections::HashSet;
 use std::default::Default;
@@ -83,6 +84,7 @@ pub struct Document {
     meta: Metadata,
     files: DataFiles,
     style: Style,
+    warnings: Warnings,
 }
 
 impl<'a> Document {
@@ -99,9 +101,15 @@ impl<'a> Document {
             meta,
             files,
             style,
+            warnings: Warnings::default(),
         }
     }
 
+    /// Return all warnings about this document.
+    pub fn warnings(&self) -> &[Warning] {
+        self.warnings.warnings()
+    }
+
     fn from_ast<P>(
         basedir: P,
         markdowns: Vec<PathBuf>,
@@ -344,7 +352,7 @@ impl<'a> Document {
                         if matches!(step.types().get(name.as_str()), Some(CaptureType::File))
                             && !filenames.contains(&text.to_lowercase())
                         {
-                            eprintln!("Found reference to unknown file {}", text);
+                            self.warnings.push(Warning::UnknownEmbeddedFile(text.to_string()));
                             okay = false;
                         }
                     }
@@ -378,10 +386,7 @@ impl<'a> Document {
             }
         }
         for filename in filenames.iter() {
-            eprintln!(
-                "WARNING: embedded file is not used by any scenario: {}",
-                filename
-            );
+            self.warnings.push(Warning::UnusedEmbeddedFile(filename.to_string()));
         }
 
         // We always succeed. Subplot's own subplot had valid cases of
@@ -402,16 +407,10 @@ impl<'a> Document {
         trace!("Found {} scenarios", scenarios.len());
         for scenario in scenarios {
             trace!("Checking that steps in scenario");
-            let mut said_scenario = false;
             for step in scenario.steps() {
                 if step.function().is_none() {
-                    if !said_scenario {
-                        eprintln!("Scenario: '{}'", scenario.title());
-                        eprintln!("  Template: '{}'", template);
-                        said_scenario = true;
-                    }
-                    eprintln!("  Step missing implementation: '{}'", step.text());
                     trace!("Missing step implementation: {:?}", step.text());
+                    self.warnings.push(Warning::MissingStepImplementation(step.text().to_string()));
                     okay = false;
                 }
             }
diff --git a/src/error.rs b/src/error.rs
index bcee4ff..31fca60 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -334,3 +334,39 @@ impl SubplotError {
 
 /// A result type for this crate.
 pub type Result<T> = std::result::Result<T, SubplotError>;
+
+/// A warning, or non-fatal error.
+///
+/// Errors prevent Subplot from producing output. Warnings don't do that.
+#[derive(Debug)]
+pub enum Warning {
+    /// Document refers to an embedded file that doesn't exist.
+    UnknownEmbeddedFile(String),
+
+    /// Embedded file is not used by any scenario.
+    UnusedEmbeddedFile(String),
+
+    /// Missing step implementation.
+    MissingStepImplementation(String),
+}
+
+/// A list of warnings.
+///
+/// Subplot collects warnings into this structure so that they can be
+/// processed at the end.
+#[derive(Debug, Default)]
+pub struct Warnings {
+    warnings: Vec<Warning>,
+}
+
+impl Warnings {
+    /// Append a warning to the list.
+    pub fn push(&mut self, w: Warning) {
+        self.warnings.push(w);
+    }
+
+    /// Return a slice with all the warnings in the list.
+    pub fn warnings(&self) -> &[Warning] {
+        &self.warnings
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 314ad2a..4bef83a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,6 +16,8 @@ extern crate pandoc_ast_08 as pandoc_ast;
 mod error;
 pub use error::Result;
 pub use error::SubplotError;
+pub use error::Warning;
+pub use error::Warnings;
 
 pub mod resource;
 
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