feat(ir): validate front-matter task steps against typed builders

Add a parse direction to the typed task builders: parse_task_step()
deserializes an authored ADO task-step mapping and validates it by
reusing the builder structs as the schema. Derive Deserialize (keyed on
ADO input names, deny_unknown_fields) on CopyFiles and the Docker@2
command variants, plus a flexible bool deserializer accepting both 	rue
and "true".

Partial coverage is safe and additive: parse_task_step returns
Ok(Some(TaskStep)) for a recognized+valid step, Ok(None) for anything not
modeled (unmapped task or non-task step) so the caller keeps the original
YAML as today's opaque passthrough, and Err only for a recognized task
with invalid inputs (missing required, unknown key, bad value, or an
input for the wrong command). Wired up for CopyFiles@2 and Docker@2 as a
proof of concept.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jamesadevine

src/compile/ir/tasks/common.rs

@@ -31,3 +31,33 @@ pub(crate) fn push_bool(t: &mut TaskStep, key: &str, value: Option<bool>) {
         t.inputs.insert(key.to_string(), bool_input(v).to_string());
     }
 }
+
+/// Deserialize an optional ADO bool-string input, accepting either a native
+/// YAML boolean (`true`) or the ADO-canonical string form (`"true"` /
+/// `"false"`). Used by the front-matter validation path in [`super::parse`] so
+/// authored task inputs match ADO's accepted shapes.
+pub(crate) fn de_opt_bool_flex<'de, D>(deserializer: D) -> Result<Option<bool>, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    use serde::Deserialize;
+
+    #[derive(Deserialize)]
+    #[serde(untagged)]
+    enum BoolOrStr {
+        Bool(bool),
+        Str(String),
+    }
+
+    match Option::<BoolOrStr>::deserialize(deserializer)? {
+        None => Ok(None),
+        Some(BoolOrStr::Bool(b)) => Ok(Some(b)),
+        Some(BoolOrStr::Str(s)) => match s.as_str() {
+            "true" => Ok(Some(true)),
+            "false" => Ok(Some(false)),
+            other => Err(serde::de::Error::custom(format!(
+                "expected a boolean or \"true\"/\"false\", got {other:?}"
+            ))),
+        },
+    }
+}

src/compile/ir/tasks/copy_files.rs

@@ -1,27 +1,44 @@
 //! Typed builder for `CopyFiles@2`.
 
-use super::common::bool_input;
+use super::common::{bool_input, de_opt_bool_flex};
 use crate::compile::ir::step::TaskStep;
+use serde::Deserialize;
 
 /// Builder for a [`TaskStep`] invoking `CopyFiles@2`.
 ///
 /// Copies files matching `contents` into `target_folder`. Optional inputs are
 /// applied through the typed setters; only those that are set are emitted.
 ///
+/// Also implements [`serde::Deserialize`] keyed on ADO input names so a
+/// front-matter task `inputs:` mapping can be parsed and validated via
+/// [`super::parse`] (required inputs enforced, unknown inputs rejected).
+///
 /// ADO task reference:
 /// <https://learn.microsoft.com/en-us/azure/devops/pipelines/tasks/reference/copy-files-v2>
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct CopyFiles {
+    #[serde(rename = "Contents")]
     contents: String,
+    #[serde(rename = "TargetFolder")]
     target_folder: String,
+    #[serde(rename = "SourceFolder", default)]
     source_folder: Option<String>,
+    #[serde(rename = "CleanTargetFolder", default, deserialize_with = "de_opt_bool_flex")]
     clean_target_folder: Option<bool>,
+    #[serde(rename = "OverWrite", default, deserialize_with = "de_opt_bool_flex")]
     over_write: Option<bool>,
+    #[serde(rename = "flattenFolders", default, deserialize_with = "de_opt_bool_flex")]
     flatten_folders: Option<bool>,
+    #[serde(rename = "preserveTimestamp", default, deserialize_with = "de_opt_bool_flex")]
     preserve_timestamp: Option<bool>,
+    #[serde(rename = "retryCount", default)]
     retry_count: Option<String>,
+    #[serde(rename = "delayBetweenRetries", default)]
     delay_between_retries: Option<String>,
+    #[serde(rename = "ignoreMakeDirErrors", default, deserialize_with = "de_opt_bool_flex")]
     ignore_make_dir_errors: Option<bool>,
+    #[serde(skip)]
     display_name: Option<String>,
 }
 

src/compile/ir/tasks/docker.rs

@@ -11,6 +11,7 @@
 //! <https://learn.microsoft.com/en-us/azure/devops/pipelines/tasks/reference/docker-v2>
 
 use crate::compile::ir::step::TaskStep;
+use serde::Deserialize;
 
 /// `Docker@2` `command` selector, carrying the per-command optional inputs.
 #[derive(Debug, Clone)]
@@ -23,12 +24,18 @@ pub enum DockerCommand {
 }
 
 /// Optionals for `Docker@2` `command: buildAndPush`.
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct DockerBuildAndPush {
+    #[serde(rename = "containerRegistry", default)]
     container_registry: Option<String>,
+    #[serde(default)]
     repository: Option<String>,
+    #[serde(rename = "Dockerfile", default)]
     dockerfile: Option<String>,
+    #[serde(rename = "buildContext", default)]
     build_context: Option<String>,
+    #[serde(default)]
     tags: Option<String>,
 }
 
@@ -64,13 +71,20 @@ impl DockerBuildAndPush {
 }
 
 /// Optionals for `Docker@2` `command: build`.
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct DockerBuild {
+    #[serde(rename = "containerRegistry", default)]
     container_registry: Option<String>,
+    #[serde(default)]
     repository: Option<String>,
+    #[serde(rename = "Dockerfile", default)]
     dockerfile: Option<String>,
+    #[serde(rename = "buildContext", default)]
     build_context: Option<String>,
+    #[serde(default)]
     tags: Option<String>,
+    #[serde(default)]
     arguments: Option<String>,
 }
 
@@ -111,11 +125,16 @@ impl DockerBuild {
 }
 
 /// Optionals for `Docker@2` `command: push`.
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct DockerPush {
+    #[serde(rename = "containerRegistry", default)]
     container_registry: Option<String>,
+    #[serde(default)]
     repository: Option<String>,
+    #[serde(default)]
     tags: Option<String>,
+    #[serde(default)]
     arguments: Option<String>,
 }
 
@@ -146,8 +165,10 @@ impl DockerPush {
 }
 
 /// Optionals for `Docker@2` `command: login`.
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct DockerLogin {
+    #[serde(rename = "containerRegistry", default)]
     container_registry: Option<String>,
 }
 
@@ -163,8 +184,10 @@ impl DockerLogin {
 }
 
 /// Optionals for `Docker@2` `command: logout`.
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct DockerLogout {
+    #[serde(rename = "containerRegistry", default)]
     container_registry: Option<String>,
 }
 

src/compile/ir/tasks/mod.rs

@@ -29,6 +29,7 @@ pub mod dotnet_core_cli;
 pub mod download_pipeline_artifact;
 pub mod extract_files;
 pub mod nuget_command;
+pub mod parse;
 pub mod powershell;
 pub mod publish_pipeline_artifact;
 pub mod publish_test_results;