breaking changes to zig build API and improved caching

 * in Zig build scripts, getOutputPath() is no longer a valid function
   to call, unless setOutputDir() was used, or within a custom make()
   function. Instead there is more convenient API to use which takes
   advantage of the caching system. Search this commit diff for
   `exe.run()` for an example.
 * Zig build by default enables caching. All build artifacts will go
   into zig-cache. If you want to access build artifacts in a convenient
   location, it is recommended to add an `install` step. Otherwise
   you can use the `run()` API mentioned above to execute programs
   directly from their location in the cache. Closes #330.
   `addSystemCommand` is available for programs not built with Zig
   build.
 * Please note that Zig does no cache evicting yet. You may have to
   manually delete zig-cache directories periodically to keep disk
   usage down. It's planned for this to be a simple Least Recently
   Used eviction system eventually.
 * `--output`, `--output-lib`, and `--output-h` are removed. Instead,
   use `--output-dir` which defaults to the current working directory.
   Or take advantage of `--cache on`, which will print the main output
   path to stdout, and the other artifacts will be in the same directory
   with predictable file names. `--disable-gen-h` is available when
   one wants to prevent .h file generation.
 * `@cImport` is always independently cached now. Closes #2015.
   It always writes the generated Zig code to disk which makes debug
   info and compile errors better. No more "TODO: remember C source
   location to display here"
 * Fix .d file parsing. (Fixes the MacOS CI failure)
 * Zig no longer creates "temporary files" other than inside a
   zig-cache directory.

This breaks the CLI API that Godbolt uses. The suggested new invocation
can be found in this commit diff, in the changes to `test/cli.zig`.

1 files changed, 49 insertions, 33 deletions

diff --git a/test/tests.zig b/test/tests.zig
index d3a27f3e94..ba713902ba 100644
--- a/test/tests.zig
+++ b/test/tests.zig
@@ -12,6 +12,7 @@ const fmt = std.fmt;
 const ArrayList = std.ArrayList;
 const builtin = @import("builtin");
 const Mode = builtin.Mode;
+const LibExeObjStep = build.LibExeObjStep;
 
 const compare_output = @import("compare_output.zig");
 const build_examples = @import("build_examples.zig");
@@ -111,12 +112,11 @@ pub fn addCliTests(b: *build.Builder, test_filter: ?[]const u8, modes: []const M
     const step = b.step("test-cli", "Test the command line interface");
 
     const exe = b.addExecutable("test-cli", "test/cli.zig");
-    const run_cmd = b.addCommand(null, b.env_map, [][]const u8{
-        b.pathFromRoot(exe.getOutputPath()),
+    const run_cmd = exe.run();
+    run_cmd.addArgs([][]const u8{
         os.path.realAlloc(b.allocator, b.zig_exe) catch unreachable,
         b.pathFromRoot(b.cache_root),
     });
-    run_cmd.step.dependOn(&exe.step);
 
     step.dependOn(&run_cmd.step);
     return step;
@@ -246,24 +246,31 @@ pub const CompareOutputContext = struct {
     const RunCompareOutputStep = struct {
         step: build.Step,
         context: *CompareOutputContext,
-        exe_path: []const u8,
+        exe: *LibExeObjStep,
         name: []const u8,
         expected_output: []const u8,
         test_index: usize,
         cli_args: []const []const u8,
 
-        pub fn create(context: *CompareOutputContext, exe_path: []const u8, name: []const u8, expected_output: []const u8, cli_args: []const []const u8) *RunCompareOutputStep {
+        pub fn create(
+            context: *CompareOutputContext,
+            exe: *LibExeObjStep,
+            name: []const u8,
+            expected_output: []const u8,
+            cli_args: []const []const u8,
+        ) *RunCompareOutputStep {
             const allocator = context.b.allocator;
             const ptr = allocator.create(RunCompareOutputStep) catch unreachable;
             ptr.* = RunCompareOutputStep{
                 .context = context,
-                .exe_path = exe_path,
+                .exe = exe,
                 .name = name,
                 .expected_output = expected_output,
                 .test_index = context.test_index,
                 .step = build.Step.init("RunCompareOutput", allocator, make),
                 .cli_args = cli_args,
             };
+            ptr.step.dependOn(&exe.step);
             context.test_index += 1;
             return ptr;
         }
@@ -272,7 +279,7 @@ pub const CompareOutputContext = struct {
             const self = @fieldParentPtr(RunCompareOutputStep, "step", step);
             const b = self.context.b;
 
-            const full_exe_path = b.pathFromRoot(self.exe_path);
+            const full_exe_path = self.exe.getOutputPath();
             var args = ArrayList([]const u8).init(b.allocator);
             defer args.deinit();
 
@@ -336,21 +343,21 @@ pub const CompareOutputContext = struct {
     const RuntimeSafetyRunStep = struct {
         step: build.Step,
         context: *CompareOutputContext,
-        exe_path: []const u8,
+        exe: *LibExeObjStep,
         name: []const u8,
         test_index: usize,
 
-        pub fn create(context: *CompareOutputContext, exe_path: []const u8, name: []const u8) *RuntimeSafetyRunStep {
+        pub fn create(context: *CompareOutputContext, exe: *LibExeObjStep, name: []const u8) *RuntimeSafetyRunStep {
             const allocator = context.b.allocator;
             const ptr = allocator.create(RuntimeSafetyRunStep) catch unreachable;
             ptr.* = RuntimeSafetyRunStep{
                 .context = context,
-                .exe_path = exe_path,
+                .exe = exe,
                 .name = name,
                 .test_index = context.test_index,
                 .step = build.Step.init("RuntimeSafetyRun", allocator, make),
             };
-
+            ptr.step.dependOn(&exe.step);
             context.test_index += 1;
             return ptr;
         }
@@ -359,11 +366,11 @@ pub const CompareOutputContext = struct {
             const self = @fieldParentPtr(RuntimeSafetyRunStep, "step", step);
             const b = self.context.b;
 
-            const full_exe_path = b.pathFromRoot(self.exe_path);
+            const full_exe_path = self.exe.getOutputPath();
 
             warn("Test {}/{} {}...", self.test_index + 1, self.context.test_index, self.name);
 
-            const child = os.ChildProcess.init([][]u8{full_exe_path}, b.allocator) catch unreachable;
+            const child = os.ChildProcess.init([][]const u8{full_exe_path}, b.allocator) catch unreachable;
             defer child.deinit();
 
             child.env_map = b.env_map;
@@ -463,8 +470,13 @@ pub const CompareOutputContext = struct {
                     exe.step.dependOn(&write_src.step);
                 }
 
-                const run_and_cmp_output = RunCompareOutputStep.create(self, exe.getOutputPath(), annotated_case_name, case.expected_output, case.cli_args);
-                run_and_cmp_output.step.dependOn(&exe.step);
+                const run_and_cmp_output = RunCompareOutputStep.create(
+                    self,
+                    exe,
+                    annotated_case_name,
+                    case.expected_output,
+                    case.cli_args,
+                );
 
                 self.step.dependOn(&run_and_cmp_output.step);
             },
@@ -490,8 +502,13 @@ pub const CompareOutputContext = struct {
                         exe.step.dependOn(&write_src.step);
                     }
 
-                    const run_and_cmp_output = RunCompareOutputStep.create(self, exe.getOutputPath(), annotated_case_name, case.expected_output, case.cli_args);
-                    run_and_cmp_output.step.dependOn(&exe.step);
+                    const run_and_cmp_output = RunCompareOutputStep.create(
+                        self,
+                        exe,
+                        annotated_case_name,
+                        case.expected_output,
+                        case.cli_args,
+                    );
 
                     self.step.dependOn(&run_and_cmp_output.step);
                 }
@@ -516,8 +533,7 @@ pub const CompareOutputContext = struct {
                     exe.step.dependOn(&write_src.step);
                 }
 
-                const run_and_cmp_output = RuntimeSafetyRunStep.create(self, exe.getOutputPath(), annotated_case_name);
-                run_and_cmp_output.step.dependOn(&exe.step);
+                const run_and_cmp_output = RuntimeSafetyRunStep.create(self, exe, annotated_case_name);
 
                 self.step.dependOn(&run_and_cmp_output.step);
             },
@@ -608,10 +624,6 @@ pub const CompileErrorContext = struct {
                 b.allocator,
                 [][]const u8{ b.cache_root, self.case.sources.items[0].filename },
             ) catch unreachable;
-            const obj_path = os.path.join(
-                b.allocator,
-                [][]const u8{ b.cache_root, "test.o" },
-            ) catch unreachable;
 
             var zig_args = ArrayList([]const u8).init(b.allocator);
             zig_args.append(b.zig_exe) catch unreachable;
@@ -628,8 +640,8 @@ pub const CompileErrorContext = struct {
             zig_args.append("--name") catch unreachable;
             zig_args.append("test") catch unreachable;
 
-            zig_args.append("--output") catch unreachable;
-            zig_args.append(b.pathFromRoot(obj_path)) catch unreachable;
+            zig_args.append("--output-dir") catch unreachable;
+            zig_args.append(b.pathFromRoot(b.cache_root)) catch unreachable;
 
             switch (self.build_mode) {
                 Mode.Debug => {},
@@ -851,7 +863,7 @@ pub const BuildExamplesContext = struct {
             zig_args.append("--verbose") catch unreachable;
         }
 
-        const run_cmd = b.addCommand(null, b.env_map, zig_args.toSliceConst());
+        const run_cmd = b.addSystemCommand(zig_args.toSliceConst());
 
         const log_step = b.addLog("PASS {}\n", annotated_case_name);
         log_step.step.dependOn(&run_cmd.step);
@@ -1118,23 +1130,28 @@ pub const GenHContext = struct {
     const GenHCmpOutputStep = struct {
         step: build.Step,
         context: *GenHContext,
-        h_path: []const u8,
+        obj: *LibExeObjStep,
         name: []const u8,
         test_index: usize,
         case: *const TestCase,
 
-        pub fn create(context: *GenHContext, h_path: []const u8, name: []const u8, case: *const TestCase) *GenHCmpOutputStep {
+        pub fn create(
+            context: *GenHContext,
+            obj: *LibExeObjStep,
+            name: []const u8,
+            case: *const TestCase,
+        ) *GenHCmpOutputStep {
             const allocator = context.b.allocator;
             const ptr = allocator.create(GenHCmpOutputStep) catch unreachable;
             ptr.* = GenHCmpOutputStep{
                 .step = build.Step.init("ParseCCmpOutput", allocator, make),
                 .context = context,
-                .h_path = h_path,
+                .obj = obj,
                 .name = name,
                 .test_index = context.test_index,
                 .case = case,
             };
-
+            ptr.step.dependOn(&obj.step);
             context.test_index += 1;
             return ptr;
         }
@@ -1145,7 +1162,7 @@ pub const GenHContext = struct {
 
             warn("Test {}/{} {}...", self.test_index + 1, self.context.test_index, self.name);
 
-            const full_h_path = b.pathFromRoot(self.h_path);
+            const full_h_path = self.obj.getOutputHPath();
             const actual_h = try io.readFileAlloc(b.allocator, full_h_path);
 
             for (self.case.expected_lines.toSliceConst()) |expected_line| {
@@ -1218,8 +1235,7 @@ pub const GenHContext = struct {
             obj.step.dependOn(&write_src.step);
         }
 
-        const cmp_h = GenHCmpOutputStep.create(self, obj.getOutputHPath(), annotated_case_name, case);
-        cmp_h.step.dependOn(&obj.step);
+        const cmp_h = GenHCmpOutputStep.create(self, obj, annotated_case_name, case);
 
         self.step.dependOn(&cmp_h.step);
     }