std.fmt: breaking API changes

added adapter to AnyWriter and GenericWriter to help bridge the gap
between old and new API

make std.testing.expectFmt work at compile-time

std.fmt no longer has a dependency on std.unicode. Formatted printing
was never properly unicode-aware. Now it no longer pretends to be.

Breakage/deprecations:
* std.fs.File.reader -> std.fs.File.deprecatedReader
* std.fs.File.writer -> std.fs.File.deprecatedWriter
* std.io.GenericReader -> std.io.Reader
* std.io.GenericWriter -> std.io.Writer
* std.io.AnyReader -> std.io.Reader
* std.io.AnyWriter -> std.io.Writer
* std.fmt.format -> std.fmt.deprecatedFormat
* std.fmt.fmtSliceEscapeLower -> std.ascii.hexEscape
* std.fmt.fmtSliceEscapeUpper -> std.ascii.hexEscape
* std.fmt.fmtSliceHexLower -> {x}
* std.fmt.fmtSliceHexUpper -> {X}
* std.fmt.fmtIntSizeDec -> {B}
* std.fmt.fmtIntSizeBin -> {Bi}
* std.fmt.fmtDuration -> {D}
* std.fmt.fmtDurationSigned -> {D}
* {} -> {f} when there is a format method
* format method signature
  - anytype -> *std.io.Writer
  - inferred error set -> error{WriteFailed}
  - options -> (deleted)
* std.fmt.Formatted
  - now takes context type explicitly
  - no fmt string

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/std/Build/Step/UpdateSourceFiles.zig b/lib/std/Build/Step/UpdateSourceFiles.zig
index d4a9565083..674e2a01c6 100644
--- a/lib/std/Build/Step/UpdateSourceFiles.zig
+++ b/lib/std/Build/Step/UpdateSourceFiles.zig
@@ -76,7 +76,7 @@ fn make(step: *Step, options: Step.MakeOptions) !void {
     for (usf.output_source_files.items) |output_source_file| {
         if (fs.path.dirname(output_source_file.sub_path)) |dirname| {
             b.build_root.handle.makePath(dirname) catch |err| {
-                return step.fail("unable to make path '{}{s}': {s}", .{
+                return step.fail("unable to make path '{f}{s}': {s}", .{
                     b.build_root, dirname, @errorName(err),
                 });
             };
@@ -84,7 +84,7 @@ fn make(step: *Step, options: Step.MakeOptions) !void {
         switch (output_source_file.contents) {
             .bytes => |bytes| {
                 b.build_root.handle.writeFile(.{ .sub_path = output_source_file.sub_path, .data = bytes }) catch |err| {
-                    return step.fail("unable to write file '{}{s}': {s}", .{
+                    return step.fail("unable to write file '{f}{s}': {s}", .{
                         b.build_root, output_source_file.sub_path, @errorName(err),
                     });
                 };
@@ -101,7 +101,7 @@ fn make(step: *Step, options: Step.MakeOptions) !void {
                     output_source_file.sub_path,
                     .{},
                 ) catch |err| {
-                    return step.fail("unable to update file from '{s}' to '{}{s}': {s}", .{
+                    return step.fail("unable to update file from '{s}' to '{f}{s}': {s}", .{
                         source_path, b.build_root, output_source_file.sub_path, @errorName(err),
                     });
                 };