cmd/go: don't include package dir in cache key when -trimpath is set

The '-trimpath' flag tells 'go build' to trim any paths from the
output files that are tied to the current workspace or toolchain. When
this flag is set, we do not need to include the package directory in
the text hashed to construct the action ID for each package.

Fixes #33772

Change-Id: I20b902d2f58019709b15864ca79aa0d9255ae707
Reviewed-on: https://go-review.googlesource.com/c/go/+/195318
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index 4564e32e65e18031b64f3cdff2326974e3d24403..626cacfe992d4e1bbab30ef5c3af9863201e35a3 100644 (file)
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -201,12 +201,12 @@ func (b *Builder) buildActionID(a *Action) cache.ActionID {
        // same compiler settings and can reuse each other's results.
        // If not, the reason is already recorded in buildGcflags.
        fmt.Fprintf(h, "compile\n")
+       // Only include the package directory if it may affect the output.
+       // We trim workspace paths for all packages when -trimpath is set.
        // The compiler hides the exact value of $GOROOT
-       // when building things in GOROOT,
-       // but it does not hide the exact value of $GOPATH.
-       // Include the full dir in that case.
+       // when building things in GOROOT.
        // Assume b.WorkDir is being trimmed properly.
-       if !p.Goroot && !strings.HasPrefix(p.Dir, b.WorkDir) {
+       if !p.Goroot && !cfg.BuildTrimpath && !strings.HasPrefix(p.Dir, b.WorkDir) {
                fmt.Fprintf(h, "dir %s\n", p.Dir)
        }
        fmt.Fprintf(h, "goos %s goarch %s\n", cfg.Goos, cfg.Goarch)

diff --git a/src/cmd/go/script_test.go b/src/cmd/go/script_test.go
index 4dcb4b4e0d5dc0a8f0d19bbdaa51224abe529b81..5e50dd14c78be4d62aeadf027ae3545a516e4c6e 100644 (file)
--- a/src/cmd/go/script_test.go
+++ b/src/cmd/go/script_test.go
@@ -441,10 +441,15 @@ func (ts *testScript) cmdCmp(neg bool, args []string) {
                // It would be strange to say "this file can have any content except this precise byte sequence".
                ts.fatalf("unsupported: ! cmp")
        }
+       quiet := false
+       if len(args) > 0 && args[0] == "-q" {
+               quiet = true
+               args = args[1:]
+       }
        if len(args) != 2 {
                ts.fatalf("usage: cmp file1 file2")
        }
-       ts.doCmdCmp(args, false)
+       ts.doCmdCmp(args, false, quiet)
 }
 
 // cmpenv compares two files with environment variable substitution.
@@ -452,13 +457,18 @@ func (ts *testScript) cmdCmpenv(neg bool, args []string) {
        if neg {
                ts.fatalf("unsupported: ! cmpenv")
        }
+       quiet := false
+       if len(args) > 0 && args[0] == "-q" {
+               quiet = true
+               args = args[1:]
+       }
        if len(args) != 2 {
                ts.fatalf("usage: cmpenv file1 file2")
        }
-       ts.doCmdCmp(args, true)
+       ts.doCmdCmp(args, true, quiet)
 }
 
-func (ts *testScript) doCmdCmp(args []string, env bool) {
+func (ts *testScript) doCmdCmp(args []string, env, quiet bool) {
        name1, name2 := args[0], args[1]
        var text1, text2 string
        if name1 == "stdout" {
@@ -484,7 +494,9 @@ func (ts *testScript) doCmdCmp(args []string, env bool) {
                return
        }
 
-       fmt.Fprintf(&ts.log, "[diff -%s +%s]\n%s\n", name1, name2, diff(text1, text2))
+       if !quiet {
+               fmt.Fprintf(&ts.log, "[diff -%s +%s]\n%s\n", name1, name2, diff(text1, text2))
+       }
        ts.fatalf("%s and %s differ", name1, name2)
 }
 

diff --git a/src/cmd/go/testdata/script/build_trimpath.txt b/src/cmd/go/testdata/script/build_trimpath.txt
index f785b0cb9ec9d112937db49dff6d540694ff333e..668f75599e77b406b0a10b4f47d92725cb183b44 100644 (file)
--- a/src/cmd/go/testdata/script/build_trimpath.txt
+++ b/src/cmd/go/testdata/script/build_trimpath.txt
@@ -1,21 +1,44 @@
 [short] skip
 
 env -r GOROOT_REGEXP=$GOROOT
-env -r WORK_REGEXP=$WORK
+env -r WORK_REGEXP='$WORK'  # don't expand $WORK; grep replaces $WORK in text before matching.
 env GOROOT GOROOT_REGEXP WORK WORK_REGEXP
 
+# A binary built without -trimpath should contain the current workspace
+# and GOROOT for debugging and stack traces.
+cd a
+go build -o hello.exe hello.go
+grep -q $WORK_REGEXP hello.exe
+grep -q $GOROOT_REGEXP hello.exe
+
+# A binary built with -trimpath should not contain the current workspace
+# or GOROOT.
 go build -trimpath -o hello.exe hello.go
 ! grep -q $GOROOT_REGEXP hello.exe
 ! grep -q $WORK_REGEXP hello.exe
+cd ..
 
+# A binary from an external module built with -trimpath should not contain
+# the current workspace or GOROOT.
 env GO111MODULE=on
 go build -trimpath -o fortune.exe rsc.io/fortune
 ! grep -q $GOROOT_REGEXP fortune.exe
 ! grep -q $WORK_REGEXP fortune.exe
 
--- hello.go --
+# Two binaries built from identical packages in different directories
+# should be identical.
+mkdir b
+cp a/go.mod a/hello.go b
+cd a
+go build -trimpath -o ../a.exe .
+cd ../b
+go build -trimpath -o ../b.exe .
+cd ..
+cmp -q a.exe b.exe
+
+-- a/hello.go --
 package main
 func main() { println("hello") }
 
--- go.mod --
+-- a/go.mod --
 module m