add detailed manifest validation errors at build time

4 files changed, 138 insertions, 101 deletions

diff --git a/src/SMAPI.ModBuildConfig/DeployModTask.cs b/src/SMAPI.ModBuildConfig/DeployModTask.cs
index 88412d92..357e02b5 100644
--- a/src/SMAPI.ModBuildConfig/DeployModTask.cs
+++ b/src/SMAPI.ModBuildConfig/DeployModTask.cs
@@ -7,7 +7,10 @@ using System.Reflection;
 using System.Text.RegularExpressions;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
+using Newtonsoft.Json;
 using StardewModdingAPI.ModBuildConfig.Framework;
+using StardewModdingAPI.Toolkit.Serialization;
+using StardewModdingAPI.Toolkit.Serialization.Models;
 using StardewModdingAPI.Toolkit.Utilities;
 
 namespace StardewModdingAPI.ModBuildConfig
@@ -75,6 +78,34 @@ namespace StardewModdingAPI.ModBuildConfig
                 this.Log.LogMessage(MessageImportance.High, $"[mod build package] Handling build with options {string.Join(", ", properties)}");
             }
 
+            // check if manifest file exists
+            FileInfo manifestFile = new(Path.Combine(this.ProjectDir, "manifest.json"));
+            if (!manifestFile.Exists)
+            {
+                this.Log.LogError("[mod build package] The mod does not have a manifest.json file.");
+                return false;
+            }
+
+            // check if the json is valid
+            Manifest manifest;
+            try
+            {
+                new JsonHelper().ReadJsonFileIfExists(manifestFile.FullName, out manifest);
+            } catch (JsonReaderException ex)
+            {
+                // log the inner exception, otherwise the message will be generic
+                Exception exToShow = ex.InnerException ?? ex;
+                this.Log.LogError($"[mod build package] Failed to parse manifest.json: {exToShow.Message}");
+                return false;
+            }
+
+            // validate the manifest's fields
+            if (!manifest.TryValidate(out string error))
+            {
+                this.Log.LogError($"[mod build package] The mod manifest is invalid: {error}");
+                return false;
+            }
+
             if (!this.EnableModDeploy && !this.EnableModZip)
                 return true; // nothing to do
 
@@ -101,7 +132,7 @@ namespace StardewModdingAPI.ModBuildConfig
                 // create release zip
                 if (this.EnableModZip)
                 {
-                    string zipName = this.EscapeInvalidFilenameCharacters($"{this.ModFolderName} {package.GetManifestVersion()}.zip");
+                    string zipName = this.EscapeInvalidFilenameCharacters($"{this.ModFolderName} {manifest.Version}.zip");
                     string zipPath = Path.Combine(this.ModZipPath, zipName);
 
                     this.Log.LogMessage(MessageImportance.High, $"[mod build package] Generating the release zip at {zipPath}...");
diff --git a/src/SMAPI.ModBuildConfig/Framework/ModFileManager.cs b/src/SMAPI.ModBuildConfig/Framework/ModFileManager.cs
index 80955f67..00f3f439 100644
--- a/src/SMAPI.ModBuildConfig/Framework/ModFileManager.cs
+++ b/src/SMAPI.ModBuildConfig/Framework/ModFileManager.cs
@@ -3,8 +3,6 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text.RegularExpressions;
-using StardewModdingAPI.Toolkit.Serialization;
-using StardewModdingAPI.Toolkit.Serialization.Models;
 using StardewModdingAPI.Toolkit.Utilities;
 
 namespace StardewModdingAPI.ModBuildConfig.Framework
@@ -113,16 +111,6 @@ namespace StardewModdingAPI.ModBuildConfig.Framework
             return new Dictionary<string, FileInfo>(this.Files, StringComparer.OrdinalIgnoreCase);
         }
 
-        /// <summary>Get a semantic version from the mod manifest.</summary>
-        /// <exception cref="UserErrorException">The manifest is missing or invalid.</exception>
-        public string GetManifestVersion()
-        {
-            if (!this.Files.TryGetValue(this.ManifestFileName, out FileInfo manifestFile) || !new JsonHelper().ReadJsonFileIfExists(manifestFile.FullName, out Manifest manifest))
-                throw new InvalidOperationException($"The mod does not have a {this.ManifestFileName} file."); // shouldn't happen since we validate in constructor
-
-            return manifest.Version.ToString();
-        }
-
 
         /*********
         ** Private methods
diff --git a/src/SMAPI.Toolkit/Serialization/Models/Manifest.cs b/src/SMAPI.Toolkit/Serialization/Models/Manifest.cs
index 8a449f0a..4f84a60d 100644
--- a/src/SMAPI.Toolkit/Serialization/Models/Manifest.cs
+++ b/src/SMAPI.Toolkit/Serialization/Models/Manifest.cs
@@ -1,9 +1,12 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Linq;
 using System.Text;
 using Newtonsoft.Json;
 using StardewModdingAPI.Toolkit.Serialization.Converters;
+using StardewModdingAPI.Toolkit.Utilities;
 
 namespace StardewModdingAPI.Toolkit.Serialization.Models
 {
@@ -103,6 +106,99 @@ namespace StardewModdingAPI.Toolkit.Serialization.Models
             this.UpdateKeys = updateKeys ?? Array.Empty<string>();
         }
 
+        /// <summary>Try to validate a manifest's fields. Fails if any invalid field is found.</summary>
+        /// <param name="error">The error message to display to the user.</param>
+        /// <returns>Returns whether the manifest was validated successfully.</returns>
+        public bool TryValidate(out string error)
+        {
+            // validate DLL / content pack fields
+            bool hasDll = !string.IsNullOrWhiteSpace(this.EntryDll);
+            bool isContentPack = this.ContentPackFor != null;
+
+            // validate field presence
+            if (!hasDll && !isContentPack)
+            {
+                error = $"manifest has no {nameof(IManifest.EntryDll)} or {nameof(IManifest.ContentPackFor)} field; must specify one.";
+                return false;
+            }
+            if (hasDll && isContentPack)
+            {
+                error = $"manifest sets both {nameof(IManifest.EntryDll)} and {nameof(IManifest.ContentPackFor)}, which are mutually exclusive.";
+                return false;
+            }
+
+            // validate DLL filename format
+            if (hasDll && this.EntryDll!.Intersect(Path.GetInvalidFileNameChars()).Any())
+            {
+                error = $"manifest has invalid filename '{this.EntryDll}' for the EntryDLL field.";
+                return false;
+            }
+
+            // validate content pack
+            else if (isContentPack)
+            {
+                // invalid content pack ID
+                if (string.IsNullOrWhiteSpace(this.ContentPackFor!.UniqueID))
+                {
+                    error = $"manifest declares {nameof(IManifest.ContentPackFor)} without its required {nameof(IManifestContentPackFor.UniqueID)} field.";
+                    return false;
+                }
+            }
+
+            // validate required fields
+            {
+                List<string> missingFields = new List<string>(3);
+
+                if (string.IsNullOrWhiteSpace(this.Name))
+                    missingFields.Add(nameof(IManifest.Name));
+                if (this.Version == null || this.Version.ToString() == "0.0.0")
+                    missingFields.Add(nameof(IManifest.Version));
+                if (string.IsNullOrWhiteSpace(this.UniqueID))
+                    missingFields.Add(nameof(IManifest.UniqueID));
+
+                if (missingFields.Any())
+                {
+                    error = $"manifest is missing required fields ({string.Join(", ", missingFields)}).";
+                    return false;
+                }
+            }
+
+            // validate ID format
+            if (!PathUtilities.IsSlug(this.UniqueID))
+            {
+                error = "manifest specifies an invalid ID (IDs must only contain letters, numbers, underscores, periods, or hyphens).";
+                return false;
+            }
+
+            // validate dependencies
+            foreach (IManifestDependency? dependency in this.Dependencies)
+            {
+                // null dependency
+                if (dependency == null)
+                {
+                    error = $"manifest has a null entry under {nameof(IManifest.Dependencies)}.";
+                    return false;
+                }
+
+                // missing ID
+                if (string.IsNullOrWhiteSpace(dependency.UniqueID))
+                {
+                    error = $"manifest has a {nameof(IManifest.Dependencies)} entry with no {nameof(IManifestDependency.UniqueID)} field.";
+                    return false;
+                }
+
+                // invalid ID
+                if (!PathUtilities.IsSlug(dependency.UniqueID))
+                {
+                    error = $"manifest has a {nameof(IManifest.Dependencies)} entry with an invalid {nameof(IManifestDependency.UniqueID)} field (IDs must only contain letters, numbers, underscores, periods, or hyphens).";
+                    return false;
+                }
+            }
+
+            error = "";
+            return true;
+        }
+
         /// <summary>Override the update keys loaded from the mod info.</summary>
         /// <param name="updateKeys">The new update keys to set.</param>
         internal void OverrideUpdateKeys(params string[] updateKeys)
diff --git a/src/SMAPI/Framework/ModLoading/ModResolver.cs b/src/SMAPI/Framework/ModLoading/ModResolver.cs
index fe56f4d2..352c22cc 100644
--- a/src/SMAPI/Framework/ModLoading/ModResolver.cs
+++ b/src/SMAPI/Framework/ModLoading/ModResolver.cs
@@ -8,7 +8,6 @@ using StardewModdingAPI.Toolkit.Framework.ModData;
 using StardewModdingAPI.Toolkit.Framework.ModScanning;
 using StardewModdingAPI.Toolkit.Framework.UpdateData;
 using StardewModdingAPI.Toolkit.Serialization.Models;
-using StardewModdingAPI.Toolkit.Utilities;
 using StardewModdingAPI.Toolkit.Utilities.PathLookups;
 
 namespace StardewModdingAPI.Framework.ModLoading
@@ -126,100 +125,23 @@ namespace StardewModdingAPI.Framework.ModLoading
                     continue;
                 }
 
-                // validate DLL / content pack fields
+                // check for dll if it's supposed to have one
+                if (!string.IsNullOrEmpty(mod.Manifest.EntryDll) && validateFilesExist)
                 {
-                    bool hasDll = !string.IsNullOrWhiteSpace(mod.Manifest.EntryDll);
-                    bool isContentPack = mod.Manifest.ContentPackFor != null;
-
-                    // validate field presence
-                    if (!hasDll && !isContentPack)
+                    IFileLookup pathLookup = getFileLookup(mod.DirectoryPath);
+                    FileInfo file = pathLookup.GetFile(mod.Manifest.EntryDll!);
+                    if (!file.Exists)
                     {
-                        mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its manifest has no {nameof(IManifest.EntryDll)} or {nameof(IManifest.ContentPackFor)} field; must specify one.");
-                        continue;
-                    }
-                    if (hasDll && isContentPack)
-                    {
-                        mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its manifest sets both {nameof(IManifest.EntryDll)} and {nameof(IManifest.ContentPackFor)}, which are mutually exclusive.");
-                        continue;
-                    }
-
-                    // validate DLL
-                    if (hasDll)
-                    {
-                        // invalid filename format
-                        if (mod.Manifest.EntryDll!.Intersect(Path.GetInvalidFileNameChars()).Any())
-                        {
-                            mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its manifest has invalid filename '{mod.Manifest.EntryDll}' for the EntryDLL field.");
-                            continue;
-                        }
-
-                        // file doesn't exist
-                        if (validateFilesExist)
-                        {
-                            IFileLookup pathLookup = getFileLookup(mod.DirectoryPath);
-                            FileInfo file = pathLookup.GetFile(mod.Manifest.EntryDll!);
-                            if (!file.Exists)
-                            {
-                                mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its DLL '{mod.Manifest.EntryDll}' doesn't exist.");
-                                continue;
-                            }
-                        }
-                    }
-
-                    // validate content pack
-                    else
-                    {
-                        // invalid content pack ID
-                        if (string.IsNullOrWhiteSpace(mod.Manifest.ContentPackFor!.UniqueID))
-                        {
-                            mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its manifest declares {nameof(IManifest.ContentPackFor)} without its required {nameof(IManifestContentPackFor.UniqueID)} field.");
-                            continue;
-                        }
-                    }
-                }
-
-                // validate required fields
-                {
-                    List<string> missingFields = new List<string>(3);
-
-                    if (string.IsNullOrWhiteSpace(mod.Manifest.Name))
-                        missingFields.Add(nameof(IManifest.Name));
-                    if (mod.Manifest.Version == null || mod.Manifest.Version.ToString() == "0.0.0")
-                        missingFields.Add(nameof(IManifest.Version));
-                    if (string.IsNullOrWhiteSpace(mod.Manifest.UniqueID))
-                        missingFields.Add(nameof(IManifest.UniqueID));
-
-                    if (missingFields.Any())
-                    {
-                        mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its manifest is missing required fields ({string.Join(", ", missingFields)}).");
+                        mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its DLL '{mod.Manifest.EntryDll}' doesn't exist.");
                         continue;
                     }
                 }
 
-                // validate ID format
-                if (!PathUtilities.IsSlug(mod.Manifest.UniqueID))
-                    mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, "its manifest specifies an invalid ID (IDs must only contain letters, numbers, underscores, periods, or hyphens).");
-
-                // validate dependencies
-                foreach (IManifestDependency? dependency in mod.Manifest.Dependencies)
+                // validate manifest
+                if (mod.Manifest is Manifest manifest && !manifest.TryValidate(out string manifestError))
                 {
-                    // null dependency
-                    if (dependency == null)
-                    {
-                        mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its manifest has a null entry under {nameof(IManifest.Dependencies)}.");
-                        continue;
-                    }
-
-                    // missing ID
-                    if (string.IsNullOrWhiteSpace(dependency.UniqueID))
-                    {
-                        mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its manifest has a {nameof(IManifest.Dependencies)} entry with no {nameof(IManifestDependency.UniqueID)} field.");
-                        continue;
-                    }
-
-                    // invalid ID
-                    if (!PathUtilities.IsSlug(dependency.UniqueID))
-                        mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its manifest has a {nameof(IManifest.Dependencies)} entry with an invalid {nameof(IManifestDependency.UniqueID)} field (IDs must only contain letters, numbers, underscores, periods, or hyphens).");
+                    mod.SetStatus(ModMetadataStatus.Failed, ModFailReason.InvalidManifest, $"its {manifestError}");
+                    continue;
                 }
             }