fix: show concise JSON parsing errors without stack trace

When syncing mods or tools, invalid JSON (e.g., unescaped backslashes
in Windows paths) would display a full stack trace, making it appear
as if the program crashed. The error was actually being caught, but
using e.full_message included the entire backtrace.

Changes:
- Use e.message instead of e.full_message in mods.rb and tools.rb
- Add comprehensive tests for JSON parsing error handling
- Verify errors are displayed concisely without stack traces
- Verify sync continues processing valid URLs after encountering errors

Before:
  Skipped; Invalid JSON: /path/to/gems/.../json.rb:353:in 'parse': ...
  [60+ lines of stack trace]

After:
  Skipped; Invalid JSON: invalid escape character in string: '\Users\...'

Testing:
- All 301 tests passing
- Added 4 new tests for JSON error handling

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: dyoung522

CHANGELOG.md

@@ -17,6 +17,7 @@ All notable changes to this project will be documented in this file.
   - Track and report both fetch failures and delete failures with detailed summaries
   - Enhanced dry-run output showing all entities that would be deleted
   - Add Firestore cache invalidation for mod/tool deletions
+- Fix JSON parsing error messages during sync to show concise error instead of full stack trace
 
 ### v2.3.0 - 2025-12-18
 

error

@@ -26,7 +26,7 @@ def info_array
               warn "Skipped; Failed to retrieve #{url}"
               next
             rescue JSON::ParserError => e
-              warn "Skipped; Invalid JSON: #{e.full_message}"
+              warn "Skipped; Invalid JSON: #{e.message}"
               next
             end.flatten.compact
           end

lib/icarus/mod/tools/sync/mods.rb

@@ -28,7 +28,7 @@ def info_array
               warn "Skipped; Failed to retrieve #{url}"
               next
             rescue JSON::ParserError => e
-              warn "Skipped; Invalid JSON: #{e.full_message}"
+              warn "Skipped; Invalid JSON: #{e.message}"
               next
             end.flatten.compact
           end

lib/icarus/mod/tools/sync/tools.rb

@@ -30,6 +30,42 @@
     it "returns an array of Modinfo objects" do
       expect(modsync.info_array).to all(be_a(Icarus::Mod::Tools::Modinfo))
     end
+
+    context "when JSON parsing fails" do
+      let(:valid_url) { "https://example.com/valid.json" }
+      let(:invalid_url) { "https://example.com/invalid.json" }
+      let(:valid_response) { { mods: [{ name: "Valid Mod", author: "Author", description: "Test" }] } }
+
+      before do
+        modsync.instance_variable_set(:@info_array, nil)
+        allow(firestore_double).to receive(:modinfo).and_return([valid_url, invalid_url])
+        allow_any_instance_of(Icarus::Mod::Tools::Sync::Helpers).to receive(:retrieve_from_url).with(valid_url).and_return(valid_response)
+        allow_any_instance_of(Icarus::Mod::Tools::Sync::Helpers).to receive(:retrieve_from_url).with(invalid_url).and_raise(
+          JSON::ParserError.new("invalid escape character in string: '\\Users\\foo\\bar' at line 1 column 10")
+        )
+      end
+
+      it "warns with a concise error message without stack trace" do
+        stderr_output = StringIO.new
+        original_stderr = $stderr
+        $stderr = stderr_output
+
+        modsync.info_array
+
+        $stderr = original_stderr
+        output = stderr_output.string
+
+        expect(output).to match(/Skipped; Invalid JSON: invalid escape character/)
+        expect(output).not_to match(/JSON::Ext::Parser/)
+        expect(output).not_to match(/lib\/ruby\/gems/)
+      end
+
+      it "skips the invalid URL and continues processing" do
+        result = modsync.info_array
+        expect(result.length).to eq(1)
+        expect(result.first.name).to eq("Valid Mod")
+      end
+    end
   end
 
   describe "#find" do

spec/icarus/mod/tools/sync/mods_spec.rb

@@ -30,6 +30,42 @@
     it "returns an array of Toolinfo objects" do
       expect(toolsync.info_array).to all(be_a(Icarus::Mod::Tools::Toolinfo))
     end
+
+    context "when JSON parsing fails" do
+      let(:valid_url) { "https://example.com/valid.json" }
+      let(:invalid_url) { "https://example.com/invalid.json" }
+      let(:valid_response) { { tools: [{ name: "Valid Tool", author: "Author", description: "Test", fileType: "EXE", fileURL: "http://example.com/tool.exe" }] } }
+
+      before do
+        toolsync.instance_variable_set(:@info_array, nil)
+        allow(firestore_double).to receive(:toolinfo).and_return([valid_url, invalid_url])
+        allow_any_instance_of(Icarus::Mod::Tools::Sync::Helpers).to receive(:retrieve_from_url).with(valid_url).and_return(valid_response)
+        allow_any_instance_of(Icarus::Mod::Tools::Sync::Helpers).to receive(:retrieve_from_url).with(invalid_url).and_raise(
+          JSON::ParserError.new("invalid escape character in string: '\\Users\\foo\\bar' at line 1 column 10")
+        )
+      end
+
+      it "warns with a concise error message without stack trace" do
+        stderr_output = StringIO.new
+        original_stderr = $stderr
+        $stderr = stderr_output
+
+        toolsync.info_array
+
+        $stderr = original_stderr
+        output = stderr_output.string
+
+        expect(output).to match(/Skipped; Invalid JSON: invalid escape character/)
+        expect(output).not_to match(/JSON::Ext::Parser/)
+        expect(output).not_to match(/lib\/ruby\/gems/)
+      end
+
+      it "skips the invalid URL and continues processing" do
+        result = toolsync.info_array
+        expect(result.length).to eq(1)
+        expect(result.first.name).to eq("Valid Tool")
+      end
+    end
   end
 
   describe "#find" do