From: Johannes Schindelin <johannes.schindelin@gmx.de>
We query `TIOCGWINSZ` in Git to determine the correct value for `COLUMNS`, and then set that environment variable.
If `TIOCGWINSZ` is not available, we fall back to the hard-coded value 80 _and still_ set the environment variable.
On Windows this is a problem. The reason is that Git for Windows uses a version of `less` that relies on the MSYS2 runtime to interact with the pseudo terminal (typically inside a MinTTY window, which is also aware of the MSYS2 runtime). Both MinTTY and `less.exe` interact with that pseudo terminal via `ioctl()` calls (which the MSYS2 runtime emulates even if there is no such thing on Windows). Since https://github.com/gwsw/less/commit/bb0ee4e76c2, `less` prefers the `COLUMNS` variable over asking ncurses itself.
But `git.exe` itself is _not_ aware of the MSYS2 runtime, or for that matter of that pseudo terminal, and has no way to call `ioctl()` or `TIOCGWINSZ`.
Therefore, `git.exe` will fall back to hard-coding 80 columns, no matter what the actual terminal size is.
But `less.exe` is totally able to interact with the MSYS2 runtime and would not actually require Git's help (which actually makes things worse here). So let's not override `COLUMNS` on Windows.
Let's just not set `COLUMNS` unless we managed to query the actual value from the terminal.
This fixes https://github.com/git-for-windows/git/issues/3235
Co-authored-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
pager: do not unnecessarily set COLUMNS on Windows
A recent upgrade of the "less" package in Git for Windows causes
problems. Here is a work-around.
Changes since v2:
* We no longer avoid setting COLUMNS based on the Operating Systems and
the presence of TIOCGWINSZ, but set a flag specifically when we
successfully queried the terminal's dimensions, and otherwise skip
the setenv(COLUMNS) call.
Changes since v1:
* The commit message was reworded to clarify the underlying issue
better.Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-982%2Fdscho%2Ffix-duplicated-lines-when-moving-in-pager-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-982/dscho/fix-duplicated-lines-when-moving-in-pager-v3
Pull-Request: https://github.com/gitgitgadget/git/pull/982
Range-diff vs v2:
1: 82099e53bbc9 ! 1: fe2ee68de43e pager: do not unnecessarily set COLUMNS on Windows
@@ Metadata
Author: Johannes Schindelin <Johannes.Schindelin@gmx.de>
## Commit message ##
- pager: do not unnecessarily set COLUMNS on Windows
+ pager: avoid setting COLUMNS when we're guessing its value
- Since https://github.com/gwsw/less/commit/bb0ee4e76c2, `less` prefers
- the `COLUMNS` variable over asking ncurses itself.
+ We query `TIOCGWINSZ` in Git to determine the correct value for
+ `COLUMNS`, and then set that environment variable.
- This is typically not a problem because we ask `TIOCGWINSZ` in Git, to
- determine the correct value for `COLUMNS`, and then set that environment
- variable.
+ If `TIOCGWINSZ` is not available, we fall back to the hard-coded value
+ 80 _and still_ set the environment variable.
- However, on Windows it _is_ a problem. The reason is that Git for
+ On Windows this is a problem. The reason is that Git for
Windows uses a version of `less` that relies on the MSYS2 runtime to
interact with the pseudo terminal (typically inside a MinTTY window,
which is also aware of the MSYS2 runtime). Both MinTTY and `less.exe`
interact with that pseudo terminal via `ioctl()` calls (which the MSYS2
runtime emulates even if there is no such thing on Windows).
+ Since https://github.com/gwsw/less/commit/bb0ee4e76c2, `less` prefers
+ the `COLUMNS` variable over asking ncurses itself.
But `git.exe` itself is _not_ aware of the MSYS2 runtime, or for that
matter of that pseudo terminal, and has no way to call `ioctl()` or
@@ Commit message
would not actually require Git's help (which actually makes things
worse here). So let's not override `COLUMNS` on Windows.
- Note: we do this _only_ on Windows, and _only_ if `TIOCGWINSZ` is not
- defined, to reduce any potential undesired fall-out from this patch.
+ Let's just not set `COLUMNS` unless we managed to query the actual value
+ from the terminal.
This fixes https://github.com/git-for-windows/git/issues/3235
+ Co-authored-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
## pager.c ##
+@@
+ static struct child_process pager_process = CHILD_PROCESS_INIT;
+ static const char *pager_program;
+
++/* Is the value coming back from term_columns() just a guess? */
++static int term_columns_guessed;
++
++
+ static void close_pager_fds(void)
+ {
+ /* signal EOF to pager */
@@ pager.c: void setup_pager(void)
- * to get the terminal size. Let's grab it now, and then set $COLUMNS
- * to communicate it to any sub-processes.
- */
-+#if !defined(WIN32) || defined(TIOCGWINSZ)
{
char buf[64];
xsnprintf(buf, sizeof(buf), "%d", term_columns());
- setenv("COLUMNS", buf, 0);
+- setenv("COLUMNS", buf, 0);
++ if (!term_columns_guessed)
++ setenv("COLUMNS", buf, 0);
}
-+#endif
setenv("GIT_PAGER_IN_USE", "true", 1);
+@@ pager.c: int term_columns(void)
+ return term_columns_at_startup;
+
+ term_columns_at_startup = 80;
++ term_columns_guessed = 1;
+
+ col_string = getenv("COLUMNS");
+- if (col_string && (n_cols = atoi(col_string)) > 0)
++ if (col_string && (n_cols = atoi(col_string)) > 0) {
+ term_columns_at_startup = n_cols;
++ term_columns_guessed = 0;
++ }
+ #ifdef TIOCGWINSZ
+ else {
+ struct winsize ws;
+- if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
++ if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col) {
+ term_columns_at_startup = ws.ws_col;
++ term_columns_guessed = 0;
++ }
+ }
+ #endif
pager.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
Show changes to pager.c +13 −3
diff --git a/pager.c b/pager.c
index 3d37dd7adaa2..52f27a6765c8 100644
--- a/pager.c
+++ b/pager.c
@@ -11,6 +11,10 @@
static struct child_process pager_process = CHILD_PROCESS_INIT;
static const char *pager_program;
+/* Is the value coming back from term_columns() just a guess? */
+static int term_columns_guessed;
+
+
static void close_pager_fds(void)
{
/* signal EOF to pager */
@@ -114,7 +118,8 @@ void setup_pager(void)
{
char buf[64];
xsnprintf(buf, sizeof(buf), "%d", term_columns());
- setenv("COLUMNS", buf, 0);
+ if (!term_columns_guessed)
+ setenv("COLUMNS", buf, 0);
}
setenv("GIT_PAGER_IN_USE", "true", 1);
@@ -158,15 +163,20 @@ int term_columns(void)
return term_columns_at_startup;
term_columns_at_startup = 80;
+ term_columns_guessed = 1;
col_string = getenv("COLUMNS");
- if (col_string && (n_cols = atoi(col_string)) > 0)
+ if (col_string && (n_cols = atoi(col_string)) > 0) {
term_columns_at_startup = n_cols;
+ term_columns_guessed = 0;
+ }
#ifdef TIOCGWINSZ
else {
struct winsize ws;
- if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
+ if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col) {
term_columns_at_startup = ws.ws_col;
+ term_columns_guessed = 0;
+ }
}
#endif
base-commit: ebf3c04b262aa27fbb97f8a0156c2347fecafafb
Johannes Schindelin via GitGitGadget