From 84f3dc1c9d2dd049e796000b329f21cf510b0990 Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Thu, 4 Mar 2021 09:56:15 -0800
Subject: [PATCH 1/3] Use repackaged lint binary

Lint references lint-classpath.jar, which does not contain any classes
by has a manifest that points to other jars for the classpath.  This
breaks dependency tracking during the build.  Use a lint tool that
is repackaged into a single jar.

Bug: 181681346
Test: m lint-check
Change-Id: I07d2b7404c18626e03c5af3ef5a75dd7f899cb0e
---
 java/lint.go | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/java/lint.go b/java/lint.go
index 827259573..af83664c6 100644
--- a/java/lint.go
+++ b/java/lint.go
@@ -329,8 +329,7 @@ func (l *linter) lint(ctx android.ModuleContext) {
 		FlagWithArg("ANDROID_SDK_HOME=", homeDir.String()).
 		FlagWithInput("SDK_ANNOTATIONS=", annotationsZipPath).
 		FlagWithInput("LINT_OPTS=-DLINT_API_DATABASE=", apiVersionsXMLPath).
-		Tool(android.PathForSource(ctx, "prebuilts/cmdline-tools/tools/bin/lint")).
-		Implicit(android.PathForSource(ctx, "prebuilts/cmdline-tools/tools/lib/lint-classpath.jar")).
+		BuiltTool("lint").
 		Flag("--quiet").
 		FlagWithInput("--project ", projectXML).
 		FlagWithInput("--config ", lintXML).

From 00d93b143f3409241cf026be71e56dd696539e16 Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Thu, 4 Mar 2021 10:00:09 -0800
Subject: [PATCH 2/3] Make common dependencies of lint use restat

Use restat for the api_versions.xml and annotations.zip dependencies
of lint so that frameworks/base changes don't always result in
rerunning lint on every module.

Bug: 181681346
Test: m lint-check
Change-Id: Ic6a540b41cf79b21441311a8baefe528a3d90d8b
---
 android/defs.go | 9 +++++++++
 java/lint.go    | 4 ++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/android/defs.go b/android/defs.go
index 38ecb0505..1a767214c 100644
--- a/android/defs.go
+++ b/android/defs.go
@@ -57,6 +57,15 @@ var (
 		},
 		"cpFlags")
 
+	// A copy rule that only updates the output if it changed.
+	CpIfChanged = pctx.AndroidStaticRule("CpIfChanged",
+		blueprint.RuleParams{
+			Command:     "if ! cmp -s $in $out; then cp $in $out; fi",
+			Description: "cp if changed $out",
+			Restat:      true,
+		},
+		"cpFlags")
+
 	CpExecutable = pctx.AndroidStaticRule("CpExecutable",
 		blueprint.RuleParams{
 			Command:     "rm -f $out && cp $cpPreserveSymlinks $cpFlags $in $out && chmod +x $out",
diff --git a/java/lint.go b/java/lint.go
index af83664c6..12e412988 100644
--- a/java/lint.go
+++ b/java/lint.go
@@ -437,13 +437,13 @@ func (l *lintSingleton) copyLintDependencies(ctx android.SingletonContext) {
 	}
 
 	ctx.Build(pctx, android.BuildParams{
-		Rule:   android.Cp,
+		Rule:   android.CpIfChanged,
 		Input:  android.OutputFileForModule(ctx, frameworkDocStubs, ".annotations.zip"),
 		Output: copiedAnnotationsZipPath(ctx),
 	})
 
 	ctx.Build(pctx, android.BuildParams{
-		Rule:   android.Cp,
+		Rule:   android.CpIfChanged,
 		Input:  android.OutputFileForModule(ctx, frameworkDocStubs, ".api_versions.xml"),
 		Output: copiedAPIVersionsXmlPath(ctx),
 	})

From 5c113d13eb64f40e5d0d4212ca112cacc7979756 Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Thu, 4 Mar 2021 10:01:34 -0800
Subject: [PATCH 3/3] Remove lint outputs to prevent showing old lint results
 on error

The lint rules dumped the text output file to stdout on error.  If the
lint binary exited without updating the output file it would show old
results.

Remove the output files before running lint, and only dump the text
output file if it exists.

Bug: 181681346
Test: m lint-check
Change-Id: I4fa962b1212e8715f234912a9a5e049d5c1540e8
---
 java/lint.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/java/lint.go b/java/lint.go
index 12e412988..50b84dc71 100644
--- a/java/lint.go
+++ b/java/lint.go
@@ -313,6 +313,7 @@ func (l *linter) lint(ctx android.ModuleContext) {
 
 	rule.Command().Text("rm -rf").Flag(cacheDir.String()).Flag(homeDir.String())
 	rule.Command().Text("mkdir -p").Flag(cacheDir.String()).Flag(homeDir.String())
+	rule.Command().Text("rm -f").Output(html).Output(text).Output(xml)
 
 	var annotationsZipPath, apiVersionsXMLPath android.Path
 	if ctx.Config().AlwaysUsePrebuiltSdks() {
@@ -361,7 +362,7 @@ func (l *linter) lint(ctx android.ModuleContext) {
 		}
 	}
 
-	cmd.Text("|| (").Text("cat").Input(text).Text("; exit 7)").Text(")")
+	cmd.Text("|| (").Text("if [ -e").Input(text).Text("]; then cat").Input(text).Text("; fi; exit 7)").Text(")")
 
 	rule.Command().Text("rm -rf").Flag(cacheDir.String()).Flag(homeDir.String())