Update: Use a better either algorithm that checks for null strings

Author: MrcSnm

source/redub/api.d

@@ -580,7 +580,7 @@ bool cleanProject(ProjectDetails d, bool showMessages)
 ArgsDetails resolveArguments(string[] args, bool isDescribeOnly = false)
 {
     import core.stdc.stdlib;
-    import std.algorithm.comparison:either;
+    import redub.misc.either;
     import std.getopt;
     import std.file;
 
@@ -690,7 +690,7 @@ ProjectDetails resolveDependencies(
 {
     import std.datetime.stopwatch;
     import redub.building.cache;
-    import std.algorithm.comparison;
+    import redub.misc.either;
     import redub.command_generators.commons;
     static import redub.parsers.single;
     static import redub.parsers.automatic;

source/redub/buildapi.d

@@ -337,7 +337,7 @@ struct BuildConfiguration
      */
     BuildConfiguration merge()(const auto ref BuildConfiguration other) const
     {
-        import std.algorithm.comparison:either;
+        import redub.misc.either;
         BuildConfiguration ret = clone;
         ret.runtimeWorkingDir = either(other.runtimeWorkingDir, ret.runtimeWorkingDir);
         ret.targetType = either(other.targetType, ret.targetType);

source/redub/misc/either.d

@@ -0,0 +1,21 @@
+module redub.misc.either;
+
+T either(T, Ts...)(T first, lazy Ts alternatives) if(alternatives.length >= 1)
+{
+    static if(is(T : char[]) || is(T : string))
+    {
+        if(first.length != 0) return first;
+        foreach(string alt; alternatives)
+            if(alt.length != 0)
+                return alt;
+        return alternatives[$-1];
+    }
+    else
+    {
+        if(first) return first;
+        foreach(alt; alternatives)
+            if(alt)
+                return alt;
+        return alternatives[$-1];
+    }
+}

source/redub/misc/find_executable.d

@@ -7,16 +7,20 @@ string findExecutable(string executableName)
     import std.path : isAbsolute, extension, buildPath;
     import std.file;
     import std.algorithm.iteration:splitter;
+
+    if(executableName.length == 0)
+        throw new Exception("Needs an executable name to find.");
     string pathEnv = getEnvVariable("PATH");
 
     version(Windows)
-        static string[] EXTENSIONS = [".exe", ".bat", ".cmd", ".com", ""];
+        static immutable string[] EXTENSIONS = [".exe", ".bat", ".cmd", ".com", ""];
     else
-        static string[] EXTENSIONS = [""];
+        static immutable string[] EXTENSIONS = [""];
+    static immutable string[] emptyExt = [""];
 
-    string[] extensionsTest = EXTENSIONS;
+    const(string)[] extensionsTest = EXTENSIONS;
     if(extension(executableName) != null)
-        extensionsTest = [""];
+        extensionsTest = emptyExt;
 
     static bool isExecutable(string tPath)
     {
@@ -44,7 +48,7 @@ string findExecutable(string executableName)
     foreach(path; splitter(pathEnv, pathSeparator))
     {
         string str = redub.misc.path.normalizePath(bufferSink, path, executableName);
-        foreach(ext; EXTENSIONS)
+        foreach(ext; extensionsTest)
         {
             bufferSink[str.length..str.length+ext.length] = ext;
             string fullPath = cast(string)buffer[0..str.length+ext.length];

source/redub/parsers/json.d

@@ -302,7 +302,6 @@ BuildRequirements parse(JSONValue json, ParseConfig cfg, out BuildConfiguration
         {
             import std.path;
             import std.exception;
-            import std.algorithm.comparison;
             import redub.package_searching.api;
             import redub.package_searching.cache;
             import std.parallelism;

source/redub/tooling/compiler_identification.d

@@ -141,11 +141,11 @@ string tryGetStr(JSONValue v, string key)
  */
 Compiler getCompiler(string compilerOrPath = "dmd", string cCompilerOrPath = null, string compilerAssumption = null, string arch = null)
 {
-    import std.algorithm.comparison:either;
+    import redub.misc.either;
     import redub.meta;
 
     JSONValue compilersInfo = getRedubMeta();
-    bool isDefault = compilerOrPath == null;
+    bool isDefault = compilerOrPath.length == 0;
     compilerOrPath = either(compilerOrPath, tryGetStr(compilersInfo, "defaultCompiler"), "dmd");
     cCompilerOrPath = either(cCompilerOrPath, tryGetStr(compilersInfo, "defaultCCompiler"), defaultCCompiler);