Better error reporting for missing build setting info subpaths

- Add error codes for overall and underlying error
- Add function to return underlying error key for pre-11.3
- Add category factory method to NSError for subpaths not found error
- Rework -loadBuildSettingInfo method to return error
- Move to new version of -loadBuildSettingInfo in code and test

Author: dempseyatgithub

BuildSettingExtractor/BuildSettingCommentGenerator.h

@@ -16,6 +16,6 @@
 
 - (NSString *)commentForBuildSettingWithName:(NSString *)buildSettingName;
 
-- (BOOL)loadBuildSettingInfo; // Primarily for testing
+- (BOOL)loadBuildSettingInfo:(NSError **)error; // In public interface for testing
 
 @end

BuildSettingExtractor/BuildSettingCommentGenerator.m

@@ -70,7 +70,7 @@ - (NSString *)commentForBuildSettingWithName:(NSString *)buildSettingName {
 
 - (NSString *)presentationNameForKey:(NSString *)key {
     if (!self.buildSettingInfoDictionary) {
-        [self loadBuildSettingInfo];
+        [self loadBuildSettingInfo:nil];
     }
 
     NSString *processedKey = [key tps_baseBuildSettingName]; // strip any conditional part of build setting
@@ -81,7 +81,7 @@ - (NSString *)presentationNameForKey:(NSString *)key {
 
 - (NSString *)descriptionForKey:(NSString *)key {
     if (!self.buildSettingInfoDictionary) {
-        [self loadBuildSettingInfo];
+        [self loadBuildSettingInfo:nil];
     }
 
     NSString *processedKey = [key tps_baseBuildSettingName]; // strip any conditional part of build setting
@@ -156,9 +156,10 @@ - (NSString *)processedDescriptionString:(NSString *)string forKey:(NSString *)k
     return processedString;
 }
 
-- (BOOL)loadBuildSettingInfo {
+// Returns an array of error strings describing unread build setting info files
+- (BOOL)loadBuildSettingInfo:(NSError **)error {
 
-    BOOL allSubpathsReadSuccessfully = YES;
+    NSMutableArray *subpathReadingErrorStrings = [[NSMutableArray alloc] init];
 
     NSString *defaultXcodePath = self.infoSource.resolvedURL.path;
     NSInteger xcodeVersion = self.infoSource.resolvedVersion;
@@ -230,20 +231,27 @@ - (BOOL)loadBuildSettingInfo {
             }
         }
         if (!foundOne) {
+            NSString *errorString = nil;
             if (buildSettingInfoSubpathList.count == 0) {
-                NSLog(@"Empty array of subpaths at index %lu", [buildSettingInfoSubpaths indexOfObject:buildSettingInfoSubpathList]);
+                errorString = [NSString stringWithFormat: @"Empty array of subpaths at index %lu", [buildSettingInfoSubpaths indexOfObject:buildSettingInfoSubpathList]];
             } else if (buildSettingInfoSubpathList.count == 1) {
-                NSLog(@"Could not read settings strings at path: %@", buildSettingInfoSubpathList[0]);
+                errorString = [NSString stringWithFormat:@"Could not read settings strings at path: %@", buildSettingInfoSubpathList[0]];
             } else {
-                NSLog(@"Could not read settings strings at these paths: %@", buildSettingInfoSubpathList);
+                errorString = [NSString stringWithFormat:@"Could not read settings strings at these paths: %@", buildSettingInfoSubpathList];
             }
-            allSubpathsReadSuccessfully = NO;
+            [subpathReadingErrorStrings addObject:errorString];
         }
     }
 
     _buildSettingInfoDictionary = infoStringFile;
+    
+    BOOL success = subpathReadingErrorStrings.count == 0;
+    
+    if (!success && error) {
+        *error = [NSError errorForSettingInfoFilesNotFound:subpathReadingErrorStrings]; 
+    }
 
-    return allSubpathsReadSuccessfully;
+    return success;
 }
 
 - (NSDictionary *)xcspecFileBuildSettingInfoForPath:(NSString *)path {

BuildSettingExtractor/Constants+Categories.h

@@ -14,9 +14,12 @@ typedef NS_ENUM(NSUInteger, BuildSettingExtractorErrorCodes) {
     ProjectSettingsNamingConflict = 102,
     NoSettingsFoundInProjectFile = 103,
     BuildSettingInfoSourceNotFound = 104,
+    BuildSettingInfoFilesNotFound = 105,
+    BuildSettingInfoSubpathNotFound = 106,
 };
 
 extern NSErrorDomain const TPSBuildSettingExtractorErrorDomain;
+extern NSString * TPSMultipleUnderlyingErrorsKey(void);
 
 #pragma mark -
 
@@ -62,6 +65,10 @@ extern NSErrorDomain const TPSBuildSettingExtractorErrorDomain;
 // Notify the user the destination folder already contains build config files
 + (NSError *)errorForDestinationContainsBuildConfigFiles;
 
+// Error that one or more expected build setting info files were not found
+// User info includes NSMultipleUnderlyingErrorsKey to report underlying errors
++ (NSError *)errorForSettingInfoFilesNotFound:(NSArray *)subpathErrorStrings;
+
 @end
 
 #pragma mark -

BuildSettingExtractor/Constants+Categories.m

@@ -134,8 +134,35 @@ + (NSError *)errorForDestinationContainsBuildConfigFiles {
     return error;
 }
 
++ (NSError *)errorForSettingInfoFilesNotFound:(NSArray *)subpathErrorStrings {
+    if (subpathErrorStrings.count == 0) {
+        [NSException raise:NSInternalInconsistencyException format:@"Attempt to create BuildSettingInfoSubpathNotFound error with no underlying errors"];
+    }
+    NSMutableArray *underlyingErrors = [[NSMutableArray alloc] init];
+    for (NSString *errorString in subpathErrorStrings) {
+        NSDictionary *subpathErrorUserInfo = @{NSLocalizedDescriptionKey:errorString};
+        NSError *subpathError = [NSError errorWithDomain:TPSBuildSettingExtractorErrorDomain code:BuildSettingInfoSubpathNotFound userInfo:subpathErrorUserInfo];
+        [underlyingErrors addObject:subpathError];
+    }
+    
+    NSDictionary *userInfo = @{NSLocalizedDescriptionKey:@"Some build info files not found.", TPSMultipleUnderlyingErrorsKey():underlyingErrors};
+    
+    NSError *error = [NSError errorWithDomain:TPSBuildSettingExtractorErrorDomain code:BuildSettingInfoFilesNotFound userInfo:userInfo];
+    
+    return error;
+}
+
 @end
 
+// Can remove once deployment target is macOS 11.3 or later
+NSString * TPSMultipleUnderlyingErrorsKey() {
+    if (@available(macOS 11.3, *)) {
+        return NSMultipleUnderlyingErrorsKey;
+    } else {
+        return @"NSMultipleUnderlyingErrorsKey";
+    }
+}
+
 #pragma mark -
 
 @implementation EmptyStringTransformer

BuildSettingExtractorTests/BuildSettingExtractorTests.m

@@ -64,8 +64,9 @@ - (void)testLoadingBuildSettingInfo
     XCTAssertNil(error);
 
     BuildSettingCommentGenerator *commentGenerator = [[BuildSettingCommentGenerator alloc] initWithBuildSettingInfoSource:infoSource];
-    XCTAssertTrue([commentGenerator loadBuildSettingInfo]);
-    
+    BOOL success = [commentGenerator loadBuildSettingInfo:&error];
+    XCTAssertTrue(success);
+    XCTAssertNil(error);    
 }
 
 - (void)testBadProjectURL