Subject: [PATCH] gc: Add option --keep-going.

From: Hartmut Goebel <[email-masked]>
Date: Thu, 11 Jul 2019 22:26:10 +0200

* guix/scripts/gc.scm (show-help, %options): Add option -k/--keep-going.
  (guix-gc): Pass value off option --keep-going on to delete-paths.
* guix/store.scm (%protocol-version): Increment to 17.
  (delete-paths) New key-word parameter `keep-going?`, pass it on to
  run-rc.
  (run-gc): New key-word parameter `keep-going?`, send value of
  keep-going? to the daemon.
* nix/libstore/store-api.hh (GCOptions): Add boolean keepGoing.
* nix/libstore/worker-protocol.hh (PROTOCOL_VERSION) Increment to 17.
* nix/nix-daemon/nix-daemon.cc (performOp)[wopCollectGarbage] Read
  keepGoing.
* nix/libstore/gc.cc (LocalStore::collectGarbage) If keepGoing is true
  print an error message instead of throwing an error.
* doc/guix.texi (Invoking guix gc): Document option --keep-going.
---
 doc/guix.texi                   |  8 +++++++-
 guix/scripts/gc.scm             |  9 ++++++++-
 guix/store.scm                  | 12 ++++++++----
 nix/libstore/gc.cc              |  7 ++++++-
 nix/libstore/store-api.hh       |  3 +++
 nix/libstore/worker-protocol.hh |  2 +-
 nix/nix-daemon/nix-daemon.cc    |  2 ++
 7 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index a3eba58..b8362d6 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -2098,7 +2098,13 @@ nothing and exit immediately.
 @itemx -d
 Attempt to delete all the store files and directories specified as
 arguments.  This fails if some of the files are not in the store, or if
-they are still live.
+they are still live (with behaviour can be changed with
+@option{--keep-going}).
+
+@item --keep-going
+@itemx -k
+Keep going when @option{--delete} is given and some of the store files
+and directories specified as arguments fail to re removed.
 
 @item --list-failures
 List store items corresponding to cached build failures.
diff --git a/guix/scripts/gc.scm b/guix/scripts/gc.scm
index bdfee43..778e9a7 100644
--- a/guix/scripts/gc.scm
+++ b/guix/scripts/gc.scm
@@ -72,6 +72,9 @@ Invoke the garbage collector.\n"))
       --clear-failures   remove PATHS from the set of cached failures"))
   (newline)
   (display (_ "
+  -k, --keep-going       keep going when some of th pathes can not be deleted"))
+  (newline)
+  (display (_ "
   -h, --help             display this help and exit"))
   (display (_ "
   -V, --version          display version information and exit"))
@@ -107,6 +110,9 @@ Invoke the garbage collector.\n"))
                 (lambda (opt name arg result)
                   (alist-cons 'action 'delete
                               (alist-delete 'action result))))
+        (option '(#\k "keep-going") #f #f
+                (lambda (opt name arg result)
+                  (alist-cons 'keep-going? #t result)))
         (option '("optimize") #f #f
                 (lambda (opt name arg result)
                   (alist-cons 'action 'optimize
@@ -228,7 +234,8 @@ Invoke the garbage collector.\n"))
              (let-values (((paths freed) (collect-garbage store)))
               (info (_ "freed ~h bytes~%") freed))))))
         ((delete)
-         (delete-paths store (map direct-store-path paths)))
+         (delete-paths store (map direct-store-path paths)
+                       #:keep-going? (assoc-ref opts 'keep-going?)))
         ((list-references)
          (list-relatives references))
         ((list-requisites)
diff --git a/guix/store.scm b/guix/store.scm
index 2023875..4276db4 100644
--- a/guix/store.scm
+++ b/guix/store.scm
@@ -137,7 +137,7 @@
             direct-store-path
             log-file))
 
-(define %protocol-version #x110)
+(define %protocol-version #x111)
 
 (define %worker-magic-1 #x6e697863)               ; "nixc"
 (define %worker-magic-2 #x6478696f)               ; "dxio"
@@ -938,7 +938,7 @@ is not an atomic operation.)  When CHECK-CONTENTS? is true, check the contents
 of store items; this can take a lot of time."
       (not (verify store check-contents? repair?)))))
 
-(define (run-gc server action to-delete min-freed)
+(define* (run-gc server action to-delete min-freed #:key (keep-going? #f))
   "Perform the garbage-collector operation ACTION, one of the
 `gc-action' values.  When ACTION is `delete-specific', the TO-DELETE is
 the list of store paths to delete.  IGNORE-LIVENESS? should always be
@@ -956,6 +956,8 @@ and the number of bytes freed."
       ;; Obsolete `use-atime' and `max-atime' parameters.
       (write-int 0 s)
       (write-int 0 s))
+    (when (>= (nix-server-minor-version server) 17)
+      (write-arg boolean keep-going? s))
 
     ;; Loop until the server is done sending error output.
     (let loop ((done? (process-stderr server)))
@@ -993,12 +995,14 @@ then collect at least MIN-FREED bytes.  Return the paths that were
 collected, and the number of bytes freed."
   (run-gc server (gc-action delete-dead) '() min-freed))
 
-(define* (delete-paths server paths #:optional (min-freed (%long-long-max)))
+(define* (delete-paths server paths #:optional (min-freed (%long-long-max))
+                       #:key (keep-going? #f))
   "Delete PATHS from the store at SERVER, if they are no longer
 referenced.  If MIN-FREED is non-zero, then stop after at least
 MIN-FREED bytes have been collected.  Return the paths that were
 collected, and the number of bytes freed."
-  (run-gc server (gc-action delete-specific) paths min-freed))
+  (run-gc server (gc-action delete-specific) paths min-freed
+          #:keep-going? keep-going?))
 
 (define (import-paths server port)
   "Import the set of store paths read from PORT into SERVER's store.  An error
diff --git a/nix/libstore/gc.cc b/nix/libstore/gc.cc
index 72eff52..6f2d8f7 100644
--- a/nix/libstore/gc.cc
+++ b/nix/libstore/gc.cc
@@ -662,8 +662,13 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
         foreach (PathSet::iterator, i, options.pathsToDelete) {
             assertStorePath(*i);
             tryToDelete(state, *i);
-            if (state.dead.find(*i) == state.dead.end())
+            if (state.dead.find(*i) == state.dead.end()) {
+              if (options.keepGoing) {
+                printMsg(lvlError, format("cannot delete path `%1%' since it is still alive") % *i);
+              } else {
                 throw Error(format("cannot delete path `%1%' since it is still alive") % *i);
+              }
+            }
         }
 
     } else if (options.maxFreed > 0) {
diff --git a/nix/libstore/store-api.hh b/nix/libstore/store-api.hh
index fa78d59..8b0f521 100644
--- a/nix/libstore/store-api.hh
+++ b/nix/libstore/store-api.hh
@@ -50,6 +50,9 @@ struct GCOptions
     /* Stop after at least `maxFreed' bytes have been freed. */
     unsigned long long maxFreed;
 
+    /* keep going even if some of the paths can not be collected */
+    bool keepGoing;
+
     GCOptions();
 };
 
diff --git a/nix/libstore/worker-protocol.hh b/nix/libstore/worker-protocol.hh
index 99c1ee2..8faf193 100644
--- a/nix/libstore/worker-protocol.hh
+++ b/nix/libstore/worker-protocol.hh
@@ -6,7 +6,7 @@ namespace nix {
 #define WORKER_MAGIC_1 0x6e697863
 #define WORKER_MAGIC_2 0x6478696f
 
-#define PROTOCOL_VERSION 0x110
+#define PROTOCOL_VERSION 0x111
 #define GET_PROTOCOL_MAJOR(x) ((x) & 0xff00)
 #define GET_PROTOCOL_MINOR(x) ((x) & 0x00ff)
 
diff --git a/nix/nix-daemon/nix-daemon.cc b/nix/nix-daemon/nix-daemon.cc
index a1fce25..b04cece 100644
--- a/nix/nix-daemon/nix-daemon.cc
+++ b/nix/nix-daemon/nix-daemon.cc
@@ -526,6 +526,8 @@ static void performOp(bool trusted, unsigned int clientVersion,
             readInt(from);
             readInt(from);
         }
+        if (GET_PROTOCOL_MINOR(clientVersion) >= 17)
+	  options.keepGoing = readInt(from) != 0;
 
         GCResults results;
 
-- 
2.7.4